See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/322090785 A systematic review investigating measurement properties of physiological tests in rugby Article · December 2017 DOI: 10.1186/s13102-017-0081-1 CITATIONS READS 3 239 8 authors, including: Matthew Chiwaridzo Sander Oorschot University of Zimbabwe Academisch Medisch Centrum Universiteit van Amsterdam 63 PUBLICATIONS   78 CITATIONS    12 PUBLICATIONS   7 CITATIONS    SEE PROFILE SEE PROFILE Jermaine Dambi Emmanuel Bonney University of Zimbabwe University of Cape Town 52 PUBLICATIONS   85 CITATIONS    18 PUBLICATIONS   45 CITATIONS    SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Burns Research View project PERF-FIT View project All content following this page was uploaded by Matthew Chiwaridzo on 02 January 2018. The user has requested enhancement of the downloaded file. Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 DOI 10.1186/s13102-017-0081-1 RESEARCH ARTICLE Open Access A systematic review investigating measurement properties of physiological tests in rugby Matthew Chiwaridzo1,3*, Sander Oorschot2, Jermaine M. Dambi1,3, Gillian D. Ferguson1, Emmanuel Bonney1,4, Tapfuma Mudawarima1,5, Cathrine Tadyanemhandu3,6 and Bouwien C. M. Smits-Engelsman1 Abstract Background: This systematic review was conducted with the first objective aimed at providing an overview of the physiological characteristics commonly evaluated in rugby and the corresponding tests used to measure each construct. Secondly, the measurement properties of all identified tests per physiological construct were evaluated with the ultimate purpose of identifying tests with strongest level of evidence per construct. Methods: The review was conducted in two stages. In all stages, electronic databases of EBSCOhost, Medline and Scopus were searched for full-text articles. Stage 1 included studies examining physiological characteristics in rugby. Stage 2 included studies evaluating measurement properties of all tests identified in Stage 1 either in rugby or related sports such as Australian Rules football and Soccer. Two independent reviewers screened relevant articles from titles and abstracts for both stages. Results: Seventy studies met the inclusion criteria for Stage 1. The studies described 63 tests assessing speed (8), agility/change of direction speed (7), upper-body muscular endurance (8), upper-body muscular power (6), upper- body muscular strength (5), anaerobic endurance (4), maximal aerobic power (4), lower-body muscular power (3), prolonged high-intensity intermittent running ability/endurance (5), lower-body muscular strength (5), repeated high-intensity exercise performance (3), repeated-sprint ability (2), repeated-effort ability (1), maximal aerobic speed (1) and abdominal endurance (1). Stage 2 identified 20 studies describing measurement properties of 21 different tests. Only moderate evidence was found for the reliability of the 30–15 Intermittent Fitness. There was limited evidence found for the reliability and/or validity of 5 m, 10 m, 20 m speed tests, 505 test, modified 505 test, L run test, Sergeant Jump test and bench press repetitions-to-fatigue tests. There was no information from high-quality studies on the measurement properties of all the other tests identified in stage 1. Conclusion: A number of physiological characteristics are evaluated in rugby. Each physiological construct has multiple tests for measurement. However, there is paucity of information on measurement properties from high-quality studies for the tests. This raises questions about the usefulness and applicability of these tests in rugby and creates a need for high-quality future studies evaluating measurement properties of these physiological tests. Trial registrations: PROSPERO CRD 42015029747. Keywords: Reliability, Validity, Responsiveness, Physiological characteristics, Rugby, Systematic review * Correspondence: matthewchiwaridzi@yahoo.co.uk 1Department of Health and Rehabilitation Sciences, Division of Physiotherapy, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa 3Rehabilitation Department, University of Zimbabwe, College of Health Sciences, P.O Box A178, Avondale, Harare, Zimbabwe Full list of author information is available at the end of the article © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 2 of 38 Background physiological characteristic required for optimal perform- Rugby (either rugby union or league) is a popular sport ance by rugby players. The construct has been evaluated played professionally or otherwise at both junior and se- using different tests such as ‘L’ run, Illinois agility run test, nior levels worldwide [1]. It is generally considered a agility 505 test, modified 505 test and change of direction physical sport characterised by multiple high-intensity speed test in the literature [6, 10, 16, 18–22]. In an at- activities interspersed with low-intensity activities [2–5]. tempt to understand the basis of selecting tests, it may be The players engage in physically demanding contests important to have an overview of all the tests that mea- such as tackles, rucks and mauls with the primary ob- sures a specific physiological construct and evaluate jective of gaining possession of the ball [6]. These con- systematically the measurement properties of the identified tests require players to possess a wide range of tests in an attempt to identify test(s) with the strongest level physiological characteristics such as strength, power and of evidence per construct. Possibly, this information can endurance which allows them to be stronger and help us understand the reasons for selection of particular fatigue-resistant [7–10]. tests for the measurement of a specific physiological There are numerous studies in the literature that have characteristic in terms of measurement properties. To our provided scientific evidence on the physiological charac- knowledge, there is no systematic review that has been teristics of rugby players. This has been necessitated by conducted to provide such information. Therefore, this sys- the drive to understand the physiological factors that dif- tematic review was conducted with the aim of addressing ferentiate between playing levels (talent identification) the following research questions: and the physiological characteristics associated with op- timal performance [1, 2, 7, 10–18]. For example, Gabbett 1. What physiological characteristics of rugby players and Seibold [15] postulated that lower body power, are evaluated in the literature and which tests are upper-body strength-endurance, and prolonged high- used to measure each identified characteristic? intensity intermittent running ability discriminated 2. What is known about the measurement properties players for team selection in semi-professional rugby (reliability, validity and responsiveness) of each league (RL) players. Smart et al. [17] found correlations identified physiological test in the sport of rugby? If between speed, repeated- sprint ability and game per- there is no information on the measurement properties formance statistics such as tackle breaks and tries scored for each test in rugby, is there any evidence available in rugby union (RU). Furthermore, Till et al. [18] com- from other closely-related intermittent, collision team pared longitudinal changes in physical qualities with sports to rugby such as Australian Rules football, career attainment status and found that advanced American football or Soccer? In case of multiple tests physical qualities such as absolute strength during the measuring the same construct, which test(s) has the adolescence period contributed significantly to the at- strongest level of evidence in terms of the measurement tainment of professional status in rugby. All these find- properties? ings suggest an important relationship between physiological characteristics and future career success, Stage 1: Methods physical performance and team selection [15, 17, 18]. This systematic review was registered on PROSPERO Today, physiological profiling of rugby players has with the registration number CRD 42015029747 [21]. become an integral aspect of the contemporary sport of This review paper was organised in stages. Stage 1 pre- rugby. It allows coaches to determine “competent” sents an overview of the physiological characteristics players with enhanced physiological capacities to with- commonly evaluated in rugby and the corresponding stand the high-intensity demands of the sport and can tests. Stage 2 presents an overview on the measurement win trophies for team, club or country [6, 7]. This forms properties of the identified physiological tests. Each stage the hallmark of talent identification programmes. Sec- was written in accordance with the Preferred Reporting ondly, understanding the physiological qualities needed Items for Systematic review and Meta-analyses in the sport of rugby may specifically inform training de- (PRISMA) guidelines by Moher et al. [23]. velopment practices of future professional players [18]. With the surge in physiological profiling, proliferation of Literature search talent identification and development programmes for A literature search was conducted using the following young rugby players [18], there is need for identification databases: Scopus, Medline via EBSCOhost and via and use of physical tests with known measurement PubMed, Academic Search Premier via EBSCOhost, properties (reliability, validity and responsiveness). A CINAHL (Cumulative Index of Nursing and Allied scoping review of the literature showed that there are Health) via EBSCOhost and Africa-Wide Information multiple tests available for measuring the same physio- via EBSCOhost. The review included studies published logical characteristic. For example, agility is a fundamental in the last 20 years between January 1, 1995, and Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 3 of 38 December 31, 2016. Additionally, a hand search was also i. Construct-related general search terms: physical conducted on reference lists of selected articles to characteristics OR physiological characteristics. augment the literature. ii. Construct-related specific search terms: speed OR agility OR flexibility. Selection criteria for the studies iii. Target population-related search terms: adult OR Sports context adolescent OR youth. There are two major variants of rugby, namely, RU and iv. Sport-related search terms: rugby OR rugby union RL. Although RU differs significantly from RL in team OR rugby league. sizes, scoring and in certain situations of tackling and when the ball goes out, there are striking similarities in Selection of articles game duration, field size, player positions, and goal posts The selection process was conducted stepwise based on [24]. There are also similarities in the physical demands recommendations for performing systematic reviews by and physiological responses elicited during game play as van Tulder et al. [25] and Reimers et al. [26]. The first both sports are predominantly aerobic in nature inter- author (MC) ran the search strategy across all databases. spersed with high-intensity efforts [5, 24]. The objective Two reviewers (JD and EB) independently reviewed the in both is to get the ball over the opposition’s goal line search results in two steps. The first step involved apply- by carrying, passing, kicking and grounding the ball. ing the inclusion criteria to select potentially relevant Therefore, because of the resemblance we included articles from titles. The abstracts of studies with titles studies on RU and RL. However, studies on the sport of considered relevant were retrieved for further inspection rugby “sevens” were excluded. in the second step [26]. Provided that the abstract fulfilled the eligibility criteria or had insufficient infor- Physiological characteristics mation for a selection decision to be made, both re- Rugby requires a blend of physiological characteristics viewers retrieved the full text to further assess for for players to cope with demands of the game [1]. The eligibility [26]. Initially, disagreements among reviewers studies included had to report on at least one physio- were discussed among themselves at the end of the se- logical characteristic operationally defined as measures lection process. In the case of further disagreements, a that assess speed, repeated-sprint ability, prolonged third (TM) reviewer intervened until a mutual consensus high-intensity intermittent running ability, agility, was reached. In addition, all retrieved articles were then muscular strength, power and endurance and maximal reviewed again against the inclusion criteria by the lead aerobic capacity. In addition, for studies to be included investigator (MC). they had to report the name of the test used to measure the physiological construct and include a detailed, repro- Data extraction ducible description of the test procedure. There was no Data extraction was performed by two independent restriction in study design applied during study people (TM and JD). Extracted data was documented selection. However, editorials, book chapters, poster and onto a Microsoft Excel data extraction form. The follow- oral conference abstracts, unpublished theses, disserta- ing data were captured for the first objective: publication tions, and case studies were excluded. Studies published details of the study (first author, year of publication), the in non-English language were also excluded. name(s) of the physiological characteristic examined in the study (captured as originally described by the Participants authors) and the name of corresponding test(s) as de- Since rugby is played competitively at junior and senior scribed in the study used to measure the physiological levels worldwide, studies included in this review had to characteristics. To enable the description of studies, involve male rugby participants from the age of 10 years additional information on sport contexts, age of partici- and above (adolescents to adults) from any country. pants, country, target population, study design and sam- Studies involving rugby participants living with disabil- ple size were also extracted. The primary author (MC) ities were excluded. acted as the data verifier, assessing the exhaustiveness and accuracy of data extracted from the included arti- Search strategy cles. Discrepancies in data extracted identified by the The search strategy was developed in consultation with verifier were communicated to the two data extractors an expert librarian in systematic reviews from University and disagreements resolved by mutual consensus. of Cape Town (UCT) libraries. The search strategy (see Additional file 1 designed for Medline via PubMed) con- Results: Stage 1 sisted of a combination of the following search themes Since Stage 1 results were used to inform the methods connected with the Boolean terms AND: and selection criteria for studies in the second stage of Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 4 of 38 the systematic review, results for Stage 1 were presented Physiological characteristics and the corresponding tests here. The electronic searches revealed 23,976 studies Table 2 provides an overview of physiological character- and after initial selection based on abstract and title, istics, corresponding tests used to measure each con- 1909 studies were potentially eligible (Fig. 1). After full- struct in rugby and the absolute number of studies that text evaluation, 70 studies were included. The majority used a specific physiological test. This review identified of the studies did not meet the inclusion criteria because 15 physiological characteristics commonly evaluated they did not report on physiological characteristics among rugby players. These include speed, repeated- (Fig. 1). sprint and effort ability, repeated high-intensity exercise performance, prolonged high-intensity intermittent run- Description of included studies ning ability/endurance, anaerobic endurance, maximal The general characteristics of the 70 included studies are aerobic power and speed, agility, lower-body muscular shown in Table 1. Briefly, the majority of the included power and strength, upper-body muscular strength and studies (n = 35, 50.0%) were conducted in Australia power, upper-body muscular endurance and abdominal alone. Only three (4.29%) studies were conducted in an endurance. However, there were no studies evaluating African country, namely, South Africa [7, 27, 28]. Of the muscle flexibility of the rugby players that met the inclu- 70 studies, 34 (48.6%) had adolescents as participants sion criteria. and six (8.57%) used both adults and adolescents. The The majority of these physiological characteristics had sample sizes varied greatly across studies from 12 to multiple tests for measurement. Overall, the 70 studies 1172 participants depending on study designs. Studies included in the review described 63 physiological tests: varied from retrospective, prospective cohort studies, ex- speed (8), upper-body muscular endurance (8), agility/ perimental with the preponderance of the studies being change of direction speed (7), upper-body muscular cross-sectional. The majority of studies (n = 50, 71.4%) power (6), upper-body muscular strength (5), prolonged involved RL participants. Two studies had participants high-intensity intermittent running ability/endurance drawn from both RL and RU [24, 29]. (5), lower-body muscular strength (5), anaerobic Fig. 1 Flow chart of the search and selection process for stage 1 articles Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 5 of 38 Table 1 General characteristics of included studies1 Author Sample ƪAge (years) Target Population Study design Country Sport Physiological construct size Appleby et al. (2012) [80] 20 24.4 ± 3.4–26.4 ± 3.4 Adults Longitudinal Australia Rugby union Strength Argus et al. (2012) [13] 112 16.6 ± 0.8–24.4 ± 2.7 Adolescents & Cross-sectional New Zealand Rugby union Strength, power Adults Atkins (2006) [103] 50 21.1 ± 4.7–22.1 ± 5.0 Adults Cross-sectional England Rugby league aHIRA Austin et al. (2013) [24] 36 24.4 ± 3–24 ± 4 Adults Test re-test Australia Rugby league & bHIEP union Baker (2009) [81] 64 19.5 ± 1.7–25.0 ± 3.3 Adults Cross-sectional Australia Rugby league Strength-endurance Baker and Newton (2008) [77] 40 22.6 ± 3.6–25.3 ± 3.4 Adults Cross-sectional Australia Rugby league Strength, power, agility, speed. Baker (2002) [78] 95 16.2 ± 1.2–23.5 ± 3.2 Adolescents & Cross-sectional Australia Rugby league Strength, power Adults Bradley et al. (2015) [5] 45 21–33 Adults Longitudinal (repeated England Rugby union Speed, strength measures) Comfort et al. (2011) [75] 18 21.7 ± 4.1 Adults Cross-sectional England Rugby league Speed, agility, power, strength Cobley et al. (2014) [47] 1172 U13-U15 players Adolescents Longitudinal United Kingdom Rugby league Muscular power, speed, change of direction speed, maximal aerobic power Darrall-Jones et al. (2015) [53] 67 15.5 ± 0.3–19.0 ± 1.1 Adolescents Cross-sectional England Rugby union Speed, agility, power, aHIRA Darrall-Jones et al. (2015b) [59] 67 15.4 ± 0.3–19.3 ± 1.2 Adolescents Cross-sectional England Rugby union Speed, aHIRA, maximal aerobic speed De Lacey et al. (2014) [104] 39 24 ± 3 Adults Cross-sectional New Zealand Rugby league Speed, strength, power Delaney et al. (2015) [72] 31 24.3 ± 4.4 Adults Cross-sectional Australia Rugby league Speed, change of direction ability, strength, power Durandt et al. (2014) [27] 174 U16-U18 players Adolescents Cross-sectional South-Africa Rugby union Speed, agility, strength, endurance, aerobic fitness Gabbett (2000) [61] 35 26.5 ± 5.1 Adults Cross-sectional Australia Rugby league Speed, power, maximal aerobic power Gabbett (2002a) [30] 159 12.3–25.1 Adolescents & Cross-sectional Australia Rugby league Power, speed, agility, estimated Adults V02MAX Meir et al. 2001 [105] 146 N/m Adults Cross-sectional Australia and Rugby league Strength, endurance speed, England agility Gabbett (2005a) [31] 240 16–18 Adolescents Cross-sectional Australia Rugby league Power, speed, agility, maximal aerobic power Gabbett (2005b) [32] 45 – Adolescents Cross-sectional Australia Rugby League Power, speed, agility, maximal aerobic power Gabbett (2005c) [33] 68 ≥ 18 Adults Cross-sectional Australia Rugby league Power, speed, agility, maximal aerobic power Gabbett (2006) [34] 415 21.1 ± 3.4–25.7 ± 5.6 Adults Cross-sectional Australia Rugby league Power, speed, agility, maximal aerobic power Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 6 of 38 Table 1 General characteristics of included studies1 (Continued) Author Sample ƪAge (years) Target Population Study design Country Sport Physiological construct size Gabbett et al. (2007) [35] 86 22.5 ± 4.9 Adults Cross-sectional Australia Rugby league Power, speed, agility, maximal aerobic power Gabbett et al. (2008a) [19] 42 23.6 ± 5.3 Adults Cross-sectional Australia Rugby league Speed, change of direction speed Gabbett et al. (2008b) [36] 35 14.1 ± 0.2–16.9 ± 0.3 Adolescents Longitudinal (repeated Australia Rugby league Speed, power, muscular measures) endurance, agility, maximum aerobic power Gabbett (2009) [73] 12 24.4 ± 3.5 Adults Cross-sectional Australia Rugby league Acceleration, power, change of direction speed Gabbett (2009b) [37] 88 13.2 ± 0.6–16.5 ± 0.3 Adolescents Cross-sectional Australia Rugby league Speed, change of direction speed, power, maximal aerobic power Gabbett et al. (2011a) [16] 58 23.8 ± 3.8 Adults Cross-sectional Australia Rugby league Speed, repeated sprint ability, change of direction speed, power, prolonged HIRA Gabbett et al. (2011b) [49] 86 23.3 ± 3.8 Adults Cross-sectional Australia Rugby league Speed, change of direction, power, repeated sprint ability, prolonged HIRA, maximal aerobic power Gabbett et al. (2013) [50] 38 23.1 ± 2.7 Adults Prospective cohort Australia Rugby league Repeated sprint ability, experimental design prolonged HIRA, maximal aerobic power. Gabbett et al. (2009c) [65] 64 15.9 ± 0.6–16.0 ± 0.2 Adolescents Cross-sectional Australia Rugby league Speed, change of direction speed, muscular power, maximal aerobic power Gabbett & Seibold (2013) [15] 32 24 ± 3 Adults Prospective cohort design Australia Rugby league Strength, strength endurance, power, prolonged HIRA Galvin et al. (2013) [29] 30 18.4 ± 1.5 Adolescents Single-blind placebo England Rugby league & Repeated sprint training, speed, controlled design union prolonged HIRA Green et al. (2011) [6] 28 19 ± 1.3–19 ± 1.7 Adolescents Cross-sectional Ireland Rugby union Speed, change of direction ability Hansen et al. (2011) [79] 40 23.7 ± 5.0 Adults Cross-sectional Australia Rugby union Speed, power Holloway et al. (2008) [70] 12 21.5 ± 2.2 Adults Cross-sectional Australia Rugby league Anaerobic endurance Jarvis et al. (2009) [10] 19 23.0 ± 5.4 Adults Cross-sectional Wales Rugby union Speed, agility, maximum aerobic power Johnston & Gabbett (2011) [51] 12 22.7 ± 2.2 Adults Randomized, Scotland Rugby league Repeated sprint ability & effort counterbalanced cross over experimental Johnston et al. (2015) [54] 31 16.5 ± 0.5 Adolescents Between groups, repeated Australia Rugby league HIRA measures experimental design Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 7 of 38 Table 1 General characteristics of included studies1 (Continued) Author Sample ƪAge (years) Target Population Study design Country Sport Physiological construct size Johnston et al. (2015b) [60] 21 19.2 ± 0.7 Adolescents Cross-sectional Australia Rugby league HIRA, muscular strength, power Kirkpatrick and Comfort 24 18.7 ± 0.9 Adolescents Cross-sectional England Rugby league Power, strength, speed (2013) [38] Krause et al. (2015) [76] 485 U12-U15 Adolescent Cross-sectional Australia Rugby union Speed, power Lombard et al. (2015) [7] 453 18.1 ± 0.7 Adolescents Repeated cross-sectional South Africa Rugby union Strength, endurance, speed design Moore and Murphy (2003) 15 22.5 ± 2.5 Adults Cross-sectional Australia Rugby union Anaerobic capacity [71] Meir et al. (2001) [58] 146 N/m Adults Cross-sectional England and Rugby league Speed, Muscle strength, power, Australia endurance, agility Parsonage et al. (2014) [39] 156 15 ± 7 Adolescents Cross-sectional UK Rugby union Power, speed, endurance capacity Pienaar and Coetzee (2013) 40 18.9 ± 0.4 Adolescents Pre-posttest, randomized South Africa Rugby union Power, acceleration, speed, [28] experimental design agility, anaerobic capacity Scott et al. (2015) [68] 55 15.6 ± 0.3–19.4 ± 0.5 Adolescents Test retest, comparative Australia Rugby league Prolonged HIRA cross-sectional Serpell et al. (2010) [74] 30 ≥ 18 Adolescents & Within subject & between Australia Rugby league Agility Adults subject experimental design Smart and Gill (2013) [42] 44 15.3 ± 1.3 Adolescents Pre-post experimental New Zealand Rugby union Strength, power, speed, control design anaerobic and aerobic running Smart et al. (2013) [52] 1161 *N/m Adults Retrospective, secondary New Zealand Rugby union Strength, power, speed, data analysis repeated sprint ability. Smart et al. (2014) [17] 510 *N/m Adults Retrospective, secondary New Zealand Rugby union Strength, speed, power, data analyses repeated sprint ability Till et al. (2016) [18] 81 U17-U19 Adolescents & Cross-sectional, United Kingdom Rugby League Speed, Muscular power, Adults Longitudinal strength Endurance, Till et al. (2014a) [69] 133 15.5–20.1 Adolescents Longitudinal England Rugby league Power, speed, endurance, strength Till et al. (2014b) [55] 75 13.0–19.9 Adolescents Longitudinal England Rugby league Power, speed, endurance, strength. Till et al. (2015) [56] 130 U16-U20 Adolescents Longitudinal England Rugby league Power, speed, endurance, strength Till and Jones (2015) [57] 121 12.8–15.5 Adolescents Longitudinal England Rugby league Power, speed, endurance Till et al. (2011) [43] 1172 13.57 ± 0.27–15.57 ± 0.27 Adolescents Longitudinal United Kingdom Rugby league Muscular power, Speed, change of direction speed, maximal aerobic uptake Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 8 of 38 Table 1 General characteristics of included studies1 (Continued) Author Sample ƪAge (years) Target Population Study design Country Sport Physiological construct size Till et al. (2013) [44] 81 13.6 ± 0.2 Adolescents Longitudinal United Kingdom Rugby League Muscular power, speed, change of direction, maximal aerobic power Till et al. (2014c) [45] 81 13.62 ± 0.24 Adolescents Longitudinal United Kingdom Rugby League Muscular power, speed, change of direction speed, maximal aerobic power Till et al. (2016b) [41] 580 U13-U15 Adolescents Longitudinal United Kingdom Rugby League Speed, Change of direction speed, Muscular power, maximal aerobic power Till et al. (2013b) [46] 1172 U13-U15 Adolescents Longitudinal United Kingdom Rugby League Speed, muscular power, change of direction speed, maximal aerobic power Till et al. (2016c) [66] 257 U15 Adolescents Longitudinal United Kingdom Rugby league Muscular power, speed, change of direction speed, maxiam aerobic power Till et al. (2015b) [67] 580 13.60 ± 0.55–13.80 ± Adolescents Cross-sectional United Kingdom Rugby League Speed, change of direction 0.72 speed, muscular power, maximal oxygen uptake. Till et al. (2010) [48] 683 13.6 ± 0.27–15.54 ± 0.27 Adolescents Longitudinal United Kingdom Rugby league Speed, change of direction speed, muscular power, maximal oxygen uptake. Vaz et al. (2014) [12] 46 26.2 ± 2.8–26.7 ± 2.9 Adults Cross-sectional Portugal Rugby union Strength, speed, maximal aerobic power Waldron et al. (2014a) [62] 28 15.1 ± 0.4–17.0 ± 0.4 Adolescents Longitudinal Australia Rugby league Speed, power, aerobic endurance Waldron et al. (2014b) [63] 13 15.1 ± 0.3–17.0 ± 0.3 Adolescents Longitudinal Australia Rugby league Speed, power, aerobic endurance Gabbett (2002b) [64] 66 24 ± 4 Adults Cross-sectional Australia Rugby league Power, speed, agility, maximal aerobic power Gabbett (2006b) [40] 77 16.7–27.3 Adolescents & Cross-sectional Australia Rugby league Speed, agility, maximal aerobic Adults power ahigh intensity running ability; b repeated high intensity exercise performance; ƪage was reported as mean ± standard deviation or range (for one sample of participants) or group range (if a study had more than two groups of participants); *N/m-not mentioned; Strength-denotes lower or upper body muscular strength; Power- denotes lower or upper body muscular power Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 9 of 38 Table 2 An overview of tests used to measure specific physiological characteristics as described in the included studies Physiological construct* Corresponding test(s) Reference(s) N Speed 10 m, 20 m and 40 m sprint test [30–41] 12 10 m, 20 m, 30, and 60 m sprint test [41–48] 8 10 m and 40 m sprint test [7, 10, 16, 27, 49, 61, 77] 7 10 m and 20 m sprint test [5, 18, 55–57, 69] 6 5 m, 10 m and 20 m sprint test [19, 29, 75] 3 10 m, 20 m and 30 m sprint test [17, 48, 52] 3 10 m and 30 m sprint test [6, 62] 2 5 m, 10 m, 20 m and 40 m sprint test [53, 59] 2 10 m and 60 m sprint test [66] 1 10 m, 20 m, 30 m and 40 m sprint test [64] 1 10 m, 30 m and 40 m sprint test [76] 1 10 m, 20 m, 30 m, 40 m and 50 m sprint test [8] 1 5 m, 10 m and 30 m sprint test [79] 1 5 m and 10 m sprint test [73] 1 15 m and 40 m sprint test [58] 1 20 m sprint test [63] 1 Repeated-sprint ability Repeated 20 m sprint test [16, 29, 49–51] 5 Rugby specific repeated speed (RS2) test [17, 52] 2 Repeated-effort ability Repeated effort ability test [51] 1 Repeated high intensity exercise Repeated high intensity exercise (RHIE) Back test [24] 1 performance Repeated high intensity exercise (RHIE) RL Forward test [24] 1 Repeated high intensity exercise (RHIE) RU Forward test [24] 1 Prolonged high-intensity Yo-yo intermittent recovery test (level 1) [15, 18, 53–56, 59, 60] 8 intermittent running ability/ Endurance Repeated 12 s sprint shuttle speed test [16, 49, 50] 3 Yo-yo intermittent recovery test (level 2) [24] 1 Multistage fitness test [57] 1 5 min run [58] 1 Maximal aerobic power/uptake Multistage fitness test [7, 8, 10, 16, 27, 30–37, 40, 29 41, 43–46, 48–50, 61–67] Yo-yo intermittent recovery test (level 1) [69] 1 30–15 Intermittent Fitness test (30–15IFT) [68] 1 1500 m run (Metabolic Fitness Index) [42] 1 Maximal aerobic speed/Anaerobic 30–15 Intermittent Fitness test (30–15IFT) [53, 59] 2 speed reserve Anaerobic endurance Triple 120 m shuttle (T120S) test [70] 1 Wingate 60 (w60) cycle test [70] 1 300 m shuttle run test [71] 1 400 m sprint test (Metabolic Fitness Index [42] 1 for Team Sports) Change of direction speed/Agility (Agility) 505 test [16, 19, 36, 37, 41, 43–49, 17 53, 65–67, 72] L-run [19, 31, 32, 34, 35, 40, 58] 7 Illinois Agility test [27, 30, 64] 3 Modified 505 test [19, 73] 2 Change of direction speed test [6, 74] 2 Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 10 of 38 Table 2 An overview of tests used to measure specific physiological characteristics as described in the included studies (Continued) Physiological construct* Corresponding test(s) Reference(s) N Agility test [75] 1 Novel agility test (no specific name given) [77] 1 Lower body muscular power Vertical (Sargent) jump test [15, 16, 30–36, 40, 49, 61, 64, 65, 73] 15 Countermovement jump test (CMJ) [18, 38, 39, 41, 43–48, 53, 55–57, 22 60, 62, 63, 66, 67, 69, 75, 76] Jump squat test [13, 75, 77–79] 5 Lower body muscular strength 1 repetition maximum (RM) back squat [5, 17, 18, 38, 55, 56, 69, 77, 80] 9 1 RM box squat [13, 42] 2 3 RM back squat [15, 60] 2 Isometric squat on force plate [75] 1 Upper body muscular power 2 kg medicine ball chest throw [41, 43–48, 57, 66] 9 20s push up test [36] 1 Overhead medicine ball throw [73] 1 Bench throw [13] 1 20s chin up test [36] 1 Plyometric Press-up [60] Upper body muscular strength 1RM bench press [5, 7, 17, 18, 27, 38, 42, 55, 56, 13 58, 69, 78, 80] 1RM chin up test [17, 42] 2 3RM bench press [15, 60] 2 Push test [27] 1 Prone row [18] 1 Upper body muscular endurance 60s push up test [36] 1 60s chin up test [36] 1 Bench press repetitions-to-fatigue at [81] 60% 1RM 1RM Bench press repetitions-to-fatigue [81] 1 at 60 kg 1RM Bench press repetitions-to-fatigue [81] at 102.5 kg Pull up test [7] 1 Body mass bench press with repetition [15] 1 30s plyometric push-up test [58] 1 Abdominal endurance 60s sit-up [58] 1 RL rugby league, RU Rugby union *The physiological characteristic is written as described in the original article endurance (4), maximal aerobic power (4), lower-body studies, 51 (72.9%) examined the speed characteristics of muscular power (3), repeated high-intensity exercise per- rugby players. Straight-line sprinting was commonly formance (3), repeated-sprint ability (2), repeated-effort measured over eight distances of 5 m, 10 m, 15 m, 20 m, ability (1), maximal aerobic speed (1) and abdominal en- 30 m, 40 m, 50 m and 60 m recorded using dual beam durance (1). Table 3 summarises the procedures for ad- electronic timing gates (Tables 2 and 3). Of the 50 studies, ministering each physiological test identified. 98% assessed the speed of rugby players over multiple distances. Twelve (24%) studies specifically used multiple Speed linear distances of 10 m, 20 m and 40 m [30–41] and eight Running speed was the most common physiological (16%) used the 10 m, 20 m, 30 m and 60 m sprint tests for characteristic evaluated among rugby players. Of the 70 the speed evaluation of rugby players [41–48]. Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 11 of 38 Table 3 A descriptive summary of procedure for the tests identified as commonly used in the included studies Physiological construct(s) Tests identified Basic description on how the tests were Outcome measures References performed in included studies Speed 5 m, 10 m, 15 m, 20 m, 30, 40 m, Players run along the 60 m distance from a Total sprint time per each distance (s) [5–8, 10, 16–19, 27, 29–49, 52, 50 m and 60 m sprint tests pre-determined starting point. Running speed 53, 55–67, 69, 73, 75–77, 79] evaluated at 5 m, 10 m, 20 m, 30 m, 40 m, 50 m and 60 m using dual beam electronic timing gates. Repeated sprinting ability (RSA) Repeated 20 m sprint tests Players perform 10 or 12 maximal effort sprints Total repeated sprint time (s), [16, 29, 49–51] over a 20 m distance with each sprint performed percentage decrement, average heart on a 20 or 30-s cycle. Recovery characterised by rate (b.min−1), peak heart rate (b.min−1), walking around the cone 10 m from the end of rating of perceived exertion. the sprint track. Rugby-specific repeated speed The test consists of three sets of three or four Mean time per sprint (s), *fatigue, [17, 52] (RS2) test individual sprints performed maximally at set mean of 12 sprints for 20 m for time intervals. Each set of sprints is separated forwards and the mean of 9 sprints by periods of standardised work where the for 30 m for backs players jog with a weighted bag. Players repeated sprints are measured using electronic timing gates over the same distance as speed (30 m for backs and 20 m for forwards and half backs). Repeated effort ability (REA) Repeated-effort test The protocol comprises of 12 × 20 m sprints Total repeated effort time(s), % [51] and tackles with each sprint commencing every decrement, average heart rate (b.min−1), 20s and the tackle performed after each 20 m peak heart rate (b.min−1), rating of sprint. perceived exertion Repeated high intensity exercise RHIE Backs test Each player complete 3 × 20 m sprints on a 20s Individual sprint time (s), sum of sprint [24] performance (RHIE) cycle. After 3 sprints, players complete 2 tackles time (s), decrement in sprint time over 10 m away with 20s recovery. This drill is the 3 sets of sprints (s) repeated three times for each participant. RHIE RL Forward test Similar to the RHIE Backs test, except that Sum of sprint times (s), decrement in [24] players complete 5 tackles in each circuit. sprint time (s) RHIE RU Forward test Each player complete 3 × 20 m sprints on a 20s Total sprint time (s), decrement in sprint [24] cycle. After 3 sprints, players complete a ‘scrum performance (s) sled shuttle’ four times. Then players repeat the sprint shuttles (3 × 20 m). After that, players tackle a tackle bag at 10 m four times Prolonged high intensity Yo-Yo intermittent recovery test Players perform 2 × 20 m runs back and forth Total distance covered (m), last level [15, 19, 53–56, 59, 60] intermittent running ability/ (level 1) at a progressively increasing speed keeping to reached Endurance a series of beeps/audio signals from compact disc. Players perform the test at level 1. Yo-Yo intermittent recovery test Same as above but the test is performed at Total distance covered (m) [24] (level 2) level 2. Repeated 12 s sprint shuttle Players perform 8 × 12 s maximal effort shuttles Total sprint distance, percentage [16, 49, 50] speed test (sprinting forward 20 m, turning 180 degrees decrement and sprinting 20 m), each shuttle performed at 48 s cycle. Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 12 of 38 Table 3 A descriptive summary of procedure for the tests identified as commonly used in the included studies (Continued) Physiological construct(s) Tests identified Basic description on how the tests were Outcome measures References performed in included studies Multistage fitness test Players run back and forth along a 20 m track Total distance covered (m) [57] keeping in time with the series of beeps on a compact disc with the speed progressively increased until volitional exhaustion. 5 min run Players are required to cover as much distance Total distance covered (m) [58] as possible around the course in a 5-min period. Maximal aerobic fitness Multistage(shuttle run) fitness Same as above Number of shuttles/laps/levels completed, [7, 8, 10, 16, 27, 30–37, 40, 41, test total distance covered (m), predicted 43–46, 48–50, 61–67] VO2MAX Yo-yo intermittent recovery test Players perform 20 m runs back and forth at a VO2MAX predicted via the equation: [69] (level 1) progressively increasing speed keeping to a distance run (m) × 0.0084 + 36.4 series of beeps/audio signals from compact disc. Players perform the test at level 1. 30–15 Intermittent Fitness test 30s shuttle runs interspersed with 15 s periods Last stage reached, running velocity (VIFT) [68] (30–15IFT) of passive recovery. Players run back and forth between 2 lines 40 m apart at a pace governed by a pre-recorded beep. 1500 m run (Metabolic Fitness Players would perform the 1500 m run on a Time taken to complete the distance (m) [42] Index for Team Sports) synthetic running track. Maximal aerobic speed/Anaerobic 30–15 Intermittent Fitness test 30s shuttle runs interspersed with 15 s periods Maximal aerobic speed (MAS), Anaerobic [53, 59] speed reserve (30–15IFT) of passive recovery. Players run back and forth speed reserve (ASR) between 2 lines 40 m apart at a pace governed by a pre-recorded beep. Anaerobic endurance Triple 120 m shuttle (T120S) test Players perform 3 sets of 120 m shuttle Time taken to complete the 120 m [70] sequences. shuttle, maximum heart rate, blood lactate, rating of perceived exertion Wingate 60 (w60) cycle test Each player will perform a 60s all out maximal Maximal heart rate, blood lactate, rating [70] effort on a cycle ergometer according to the of perceived exertion Wingate protocol. 300 m shuttle run test Players sprint maximally between two lines, 15 Total time to complete the run (s) [51] times, for a total distance of 300 m. 400 m sprint test (Metabolic Players run maximally an entire lap of the track Time to complete the run (s) [42] Fitness Index for Team Sports) for 400 m. Agility/change of direction speed 505 test Players assume a starting position 10 m from Total time taken (s) [16, 19, 36, 37, 41, 43–49, 53, (CODS) timing gates. They accelerate as quickly as 65–67, 72] possible along the 15-m distance, pivot on the 5 m line or turn 180 degrees at the 15 m mark and return as quickly as possible through the timing gates placed 5 m from a designated turning point L-run Three cones placed 5 m apart in an ‘L’ shape. Total time taken (s) [19, 31, 32, 34, 35, 40, 58] Players run as quickly as possible along the 5 m, turn left, run forward 5 m, turn 180 degrees Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 13 of 38 Table 3 A descriptive summary of procedure for the tests identified as commonly used in the included studies (Continued) Physiological construct(s) Tests identified Basic description on how the tests were Outcome measures References performed in included studies and follow same course to finish and dual beam electronic timing gates used to record time. Illinois Agility test Players start lying in prone on the starting line. Total time taken to complete the [27, 30, 64] On a signal the players stand up and accelerate course (s) towards and around the cones set up. They can sprint for 9 m return to the starting line; they swerve in and out of the four cones completing two 9 m sprints to finish the agility course. Modified 505 test Two timing gates placed 5 m apart from s Total time taken to complete the [19, 73] designated turning point; unlike the traditional course (s) 505 test where players start at 10 m from the timing gates and therefore 15 m from the turning point, players start 5 m from the timing gates, pivot on the 5 m line and return as quickly as possible through the timing gates Change of direction speed test Players sprint forward 5 m then perform a 45 Total time taken to complete the [6, 74] degree change of direction manoeuvre to pass course (s) through either left or right finish gate. Agility test Players sprint 5 m through the first timing gates Total time taken to complete the [75] to the second timing gates and sprint back to course (s) the third timing gate positioned at the starting line 5 m from the first and sprint back to the fourth timing gate positioned 5 m away from the second time to finish the course Novel agility test (no specific Players sprint 1 m at a 45 degree angle, turn Total time taken to complete the [77] name given) around a marker cone, sprint at 45 degrees for course (s) 10 m back to starting line. Here they make 135 degree turn around another cone and sprint 20 m in a straight line perpendicular to the goal line Lower body muscular power Vertical jump test Using a Yardstick device or a board, players Vertical jump height calculated as the [15, 16, 30–36, 40, 42, 49, 61, 64, stand with feet flat on the ground, fully distance from the highest point reached 65, 73] extended arms and hands, and mark the during and the highest reaching during standing reach height. After assuming a crouch the vertical jump position, players spring upward and touch the yardstick device or the board at the highest possible point. Countermovement jump test Players put hands on hips and jump from the Jump height, peak power, vertical power [18, 38, 39, 41, 43–48, 53, 55–57, (CMJ) jump mat or portable force plate from a was estimated by equation: CMJ 60, 62, 63, 66, 67, 69, 75, 76] standing position moving from a self-selected power (W) =61.9 × Jump height + 36.0 × depth in squatting and jump explosively as far body mass-1822. as possible. A Takei vertical jump metre may be used. Jump squat test Mechanical power output [13, 75, 77–79] Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 14 of 38 Table 3 A descriptive summary of procedure for the tests identified as commonly used in the included studies (Continued) Physiological construct(s) Tests identified Basic description on how the tests were Outcome measures References performed in included studies Players self-select foot position and lower the Olympic bar 40 kg to a self-selected depth and then the players are required to jump as explosively as possible. The bar will be resting on upper trapezius. Loaded jump squat may have a resistance of 20 kg to 100kgs conducted using the Plyometric Power System (PPS) or 40 kg jump squat from a force plate. Lower body muscular strength One repetition maximum back Using an Olympic bar and free weights, players Maximum weight lifted (kgs) [5, 17, 18, 38, 55, 56, 69, 77, 80] squat (1RM BS) back squat until the top of the thigh is parallel with the ground and return to a standing position to record one repetition maximum. Isometric squat on force plate Players stand on a force plate with the bar of a Peak force generated (n) [75] Smith Machine resting on upper trapezius at a height which results in an angle of 135 degrees knee flexion. 1 RM box squat Players use a self-selected foot position and One repetition maximum (kgs) [13, 42] lower themselves to sitting position briefly on the box and then return to standing position 3RM full squat exercise Players perform this with the free weight Maximum weight lifted (kgs) [15] Olympic-style barbell. Players lower their body until thighs are past parallel with the floor and fully extend the hip and knee joints Upper body muscular strength One repetition maximum Players in supine, feet flat on floor, hips and Maximum weight lifted (kg) [5, 7, 17, 27, 38, 42, 55, 56, 58, bench press (1RM BP) shoulders in contact with the bench, lower the 69, 78, 80] bar to touch the chest and push the bar until the elbows are locked out. 3RM bench press The test is performed as above at three Maximum weight lifted (kg) [15, 60] repetition maximum 1RM chin up test Players use a reverse underhand grip (palms One repetition maximum (kgs) [17, 42] facing towards face). Players instructed to start from a stationary position with arms fully extended and complete a repetition with the chin moving over the bar Push-Up test Players begin in prone, with hands on the floor, The number of push-ups in one [27] thumbs shoulder width apart and elbows fully minute (n) extended. Players are instructed to descend to the tester fist placed on the floor below the players’ sternum and then ascend until the elbows are straight. 1RM Prone row Participants lay face down on a bench with the Maximum weight lifted (kg) [18] bench height determined by the players reach when the arms are fully extended. Participants have to pull the barbell towards the bench and Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 15 of 38 Table 3 A descriptive summary of procedure for the tests identified as commonly used in the included studies (Continued) Physiological construct(s) Tests identified Basic description on how the tests were Outcome measures References performed in included studies the lift will be recorded if both sides of the barbell touch the bench Upper body muscular power 20s push up test Players assume prone position, body lowered Time taken to complete 20 full push [36] until the elbows are 90 degrees, followed by a ups (s) return to the starting position with arms fully extended. 20s chin up test Players assume a hanging position on the bar, Maximum number of chin-ups in 20 s [36] hands shoulder width apart with supinated grip and arms extended. Players are to raise the body until the chin touched the top of the bar with the head in neutral position. Overhead ball throw test Players stand with 1 ft aligned with the a line Maximum distance thrown (m) [73] marked on the ground facing the throwing direction, with a 3 kg medicine ball held in both hands behind the head, each player is required to plant the front foot with the toe behind the line and to throw the medicine ball overhead as far as possible. Chest throw test Players throw a 2 kg medicine ball horizontally Maximum distance thrown (m) [41, 43–48, 57, 66] as far as possible while seated with the back against the wall Bench throw test Players use a self-selected hand position and Maximum weight thrown (kgs) [13] lower the bar to a self-selected depth approximately 90 degrees at the elbow and then throw or propel the bar vertically as explosively as possible. Upper body muscular endurance 60s push up test Players assume prone position, body lowered Maximum number of push-ups in 60s [36] until the elbows are 90 degrees, followed by a return to the starting position with arms fully extended. 60s chin up test Players assume a hanging position on the bar, Maximum number of chin ups in 60s [36] hands shoulder width apart with supinated grip and arms extended. Players are to raise the body until the chin touched the top of the bar with the head in neutral position. Bench Press repetitions-to- Players perform bench press repetitions as Number of repetitions (n) [81] fatigue (BP RTF) possible till fatigue at two markedly different resistances of 60-kgs and 102.5-kgs Bench press repetitions-to- Players perform bench press repetitions as Number of repetitions at 60% 1RM BP [81] fatigue at 60% 1RM possible till fatigue with a resistance of 60% of their one repetition maximum bench press Pull up test Using an underhand grip, and the hands Maximal number of completed pull-ups [7] 10–15 cm apart, players start in the hanging position and ascended to a position with the Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 16 of 38 Table 3 A descriptive summary of procedure for the tests identified as commonly used in the included studies (Continued) Physiological construct(s) Tests identified Basic description on how the tests were Outcome measures References performed in included studies chin above the bar and then return to starting position with arms extended. Body mass bench press with Using players body mass as resistance for as Number of repetitions (n) [15] repetition many repetitions as possible until fatigue 30s Plyometric push up Participants would take a push-up position Maximum number of repetitions in [58] supporting self on the palm of left or right designated time period hand with the other hand placed on the top of a 5 kg medicine ball. The players then lower themselves to the ground until elbows are 90 degrees; they then forcefully pushes back with complete extension of the arms, while shifting the hand on the ground across to the new position on the medicine ball. Similarly, the hand on the ball shift across to a position approximately 2 shoulder widths on the opposite side of the ball Abdominal endurance 60s Sit up Participants would sit with feet flat on the floor Maximum number of repetitions in 60s [58] and held in position by another player. The arms would be crossed at the shoulders and knees bent at an angle approximately 90 degrees. On command, the players would curl the trunk so that elbows touch the front of the thighs and then return to starting position VO2MAX- maximal aerobic power estimated using regression equations; s = seconds; *calculated as a percent change in sprint time predicted from the linearized change derived from all sprints performed; b.min −1 = beats per minute; RL = Rugby League; RU = Rugby Union; m =meters; vVo2max = velocity at maximal oxygen uptake also known as MAS (maximal aerobic speed); ASR = Anaerobic speed reserve calculated as the difference between individual maximum velocity (maxV) and MAS; N = newton; n = number of repetitions; kgs = Kilograms; 1RM bench press-one repetition maximum bench press Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 17 of 38 Repeated sprint and effort ability [68], 1500 m run [42] and the Yo-Yo IRT1 [69]. Maximal There were seven (10.0%) studies that evaluated repeated- aerobic speed was evaluated using the 30–15 Intermit- sprint abilities of rugby players. However, only two tests tent Fitness test (31-15IFT) [53, 59]. The test involves were commonly used in these studies to evaluate the con- performing 30s shuttle runs conducted at a pace gov- struct. The Repeated 20 m Sprint test was used in five of erned by a pre-recorded beep and interspersed with 15 s the seven studies [16, 29, 49–51]. The test involves players periods of passive recovery. The test begins at 8 km/h performing 10 or 12 maximal effort sprints over a 20 m and increased to 0.5 km/h at each successive running distance with each sprint performed on a 20 or 30s cycle shuttle [53]. [16, 29, 49–51]. In addition, there were two studies that evaluated the repeated sprint abilities of rugby partici- Anaerobic endurance pants using the Rugby-Specific Repeated Speed (RS2) Three (4.28%) studies assessed the anaerobic endurance test [17, 52]. The Repeated-Effort Ability test was used in of rugby players. One study compared results of rugby one study to investigate the physiological characteristic of players on two tests of anaerobic endurance: Triple repeated-effort ability in rugby players [51]. The protocol 120 m (T120S) test and the Wingate 60 (w60) cycle comprises of 12 × 20 m sprints and tackles with each test [70]. Other tests used in singular studies included sprint commencing every 20s and the tackle performed the 300 m Shuttle Run test [71] and the 400 m Sprint after each 20 m sprint [51]. test [42]. Repeated high-intensity exercise performance Change of direction speed/agility The ability to perform repeated high-intensity exercises The change of direction speed/agility of rugby players by rugby players was assessed using specifically devel- was commonly measured in a number of studies. It was oped Repeated High-Intensity Exercise (RHIE) tests. the third most commonly measured physiological char- Three tests were used in a study by Austin et al. [24] acteristic in the included studies. In total, 33 (47.1%) and were modified for RU backline players, RU forward studies examined the change of direction speed or agility players and RL forward players. of rugby players. Of these studies, 17 (51.5%) used the 505 test [16, 19, 36, 37, 41, 43–49, 53, 65–67, 72] and seven Prolonged high-intensity intermittent running ability/ (21.2%) used the L-run test [19, 31, 32, 34, 35, 40, 58]. endurance The 505 test involves players assuming a starting position Fourteen (20.0%) studies investigated the measurement 10 m from timing gates and accelerate as quickly as pos- of a physiological characteristic termed “prolonged sible along the 15-m distance, pivot on the 5 m line or high-intensity intermittent running ability” or endurance turn 180 degrees at the 15 m mark and return as quickly [15, 16, 18, 24, 49, 50, 53–60]. Of the 14 included stud- as possible through the timing gates placed 5 m from a ies, eight used the Yo-Yo Intermittent Recovery Level designated turning point [16, 19, 36, 37, 49, 53, 72]. On 1 (Yo-Yo IRT1) test [15, 18, 53–56, 59, 60] and three the other hand, the L run involves three cones placed 5 m utilised the Repeated-12 s Sprint Shuttle Speed test apart in an ‘L’ shape and players have to run as quickly as [15, 49, 50]. The Yo-Yo IRT1 involves performing 2 × possible along the 5 m, turn left, run forward 5 m, turn 20 m runs back and forth at a progressively increasing 180 degrees and follow same course to finish [19, 31, 32, speed keeping to a series of beeps/audio signals from 34, 35, 40]. Other tests used in the included studies are compact disc [15, 53, 54]. The Repeated 12 s Sprint Shut- the Illinois Agility test (n = 3) [27, 30, 64], Modified 505 tle speed test involves players performing 8 × 12 s max- test (n = 2) [19, 73] and Change of Direction Speed test imal effort shuttles (sprinting forward 20 m, turning 180 (CODS) (n = 2) [6, 74]. degrees and sprinting 20 m) and each shuttle is performed at 48 s cycle [16, 49, 50]. In addition, there was only one Lower-body muscular power and strength study that evaluated the construct of “prolonged high- Lower-body muscular power was the second most com- intensity intermittent running ability” using the Yo-Yo monly investigated physiological characteristic in rugby Intermittent Recovery Level 2 (Yo-Yo IRT2) test [24]. participants. Of the 70 studies, 42 (60.0%) studies included in this review examined that construct. Of Maximal aerobic power and speed these studies, 15 (35.7%) used the Vertical Jump (VJ) test Of the 70 studies, 32 (45.7%) studies estimated the max- [15, 16, 30–36, 40, 42, 49, 61, 64, 65, 73]. The VJ in- imal aerobic power of rugby players. Of these studies, 29 volves using a Yardstick device or a board and players (90.6%) used the Multistage Fitness test [7, 8, 10, 16, 27, are instructed to stand with feet flat on the ground, 30–37, 40, 41, 43–46, 48–50, 61–67]. Other tests used in fully extended arms and hands, and mark the standing singular studies to estimate maximal aerobic power in- reach height. After assuming a crouch position, cluded the 30–15 Intermittent Fitness test (30–15IFT) players are requested to spring upward and touch the Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 18 of 38 yardstick device or the board at the highest possible Stage 2: Methods point [15, 16, 30–36, 40, 42, 49, 61, 64, 65, 73]. Twenty- Stage 1 allowed us to identify tests commonly used for two (52.4%) studies used the Countermovement Jump the measurement of physiological characteristics of (CMJ) test [18, 38, 39, 41, 43–48, 53, 55–57, 59, 60, 62, 63, speed, repeated sprint ability and effort, repeated high- 66, 67, 69, 75, 76]. The difference in the two vertical intensity exercise performance, prolonged high-intensity jump tests is that the CMJ involves participants stand- intermittent running ability/endurance, maximal aerobic ing with their hands positioned on the hips and usually power and speed, anaerobic endurance, change of direc- jump from a jump mat as high as possible [18]. The Jump tion speed/agility, lower and upper –body muscular Squat (JS) test was used in five studies [13, 75, 77–79]. strength, power, and abdominal endurance. Briefly, the Of the 70 studies, 14 (20.0%) assessed lower-body second stage of the systematic review was conducted to muscular strength of rugby players. The most frequently provide evidence on the measurement properties of each used test was the One Repetition Maximum Back Squat identified physiological test from Stage 1. The ultimate (1RM BS). The test was used in nine of the fourteen aim, however, was to identify one physiological test per studies [5, 17, 18, 38, 55, 56, 69, 77, 80]. Using an Olym- physiological construct with the strongest level of evi- pic bar or free weights, players are instructed to back dence on measurement properties on best evidence squat until the top of the thigh is parallel with the synthesis. ground and return to a standing position to record 1RM [5, 17, 38, 55, 56, 69, 77, 80]. In addition, two studies Literature search, search strategy and eligibility criteria used the 1RM Box Squat [13, 42] and 3RM Back Squat The electronic databases used for literature search in [15, 60], respectively. Stage 1 were used for Stage 2. Initially, we searched specifically for full-text studies with the primary purpose of investigating the measurement properties Upper-body muscular power and strength (reliability, validity and responsiveness) of the previ- Nineteen (27.1%) studies evaluated the upper-body ously identified physiological tests in male rugby par- muscular strength of rugby players. Of these studies, ticipants. This was done for the determination of 13 (68.4%) used the 1RM Bench Press [5, 7, 17, 18, physiological tests validated in the population of 27, 38, 42, 55, 56, 58, 69, 78, 80]. The 1RM BP test interest to the researcher (MC) for his future studies involves players in supine, feet flat on floor, hips and using rugby participants [21, 82]. However, provided shoulders in contact with the bench. The players are that there was no satisfactory information found on instructed to lower the bar to touch the chest and the measurement properties for certain physiological push the bars until the elbows are locked out, tests in rugby studies, it was pre-planned that we recording the 1RM [5, 7, 17, 27, 38, 42, 55, 56, 69, 78, 80]. would search for the evidence from clinimetric studies Two studies used the 1RM Chin-Up test [17, 42] and on related, intermittent, collision team sports such as Aus- the 3RM Bench Press [15, 60]. On the other hand, there tralian Rules football (AFL), American football, Gaelic were 12 (17.1%) studies that examined that upper-body football and Soccer. But, included studies from related muscular power for rugby players. The frequently used sports had to have a similar description of the pro- test in the included studies was the 2 kg Medicine Ball cedure of the test as described in rugby-related Chest Throw [41, 43–48, 57, 66]. Other tests used in studies. In cases where there were major adjustments singular studies included the 20s Push-Up and 20s according to the researcher (MC) in the procedure of Chin-Up tests [36], Overhead Medicine Ball Throw test test between sports such studies were excluded. A [73], Bench Throw test [13]. search strategy proposed by Terwee et al. [83] guided the selection of keywords (see Additional file 2). The Upper-body and abdominal muscular endurance strategy for searching clinimetric studies in rugby and Of the included studies, upper body muscular endurance related sports consisted of a combination of following was assessed in five studies only (7.14%). One singular search themes (i, ii, iii, iv) and (i, ii, iv, v), respect- study utilised two tests: 60s Push-Up and Chin-Up tests ively, connected with the Boolean term AND: [36]. Another study used the 1RM Bench Press Repetitions-to-Fatigue test at 60 kg, 102.5 kg and at 60% i. Test-specific terms: Vertical jump test OR Yo-Yo of 1RM [81]. Other tests used in singular studies in- intermittent recovery test OR repeated 20 m sprint cluded the Pull-Up test [7] and the body mass Bench test. Press with repetition test [15] and the 30s Plyometric ii. Measurement property-related terms: Psychometric* push-up test [58]. Abdominal endurance was identi- OR measurement* OR clinimetric*. fied in one study and was assessed using the 60s iii. Rugby-related terms: rugby OR rugby union OR Sit-Up test [58]. rugby league. Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 19 of 38 iv. Target population-related search terms: adult OR Best evidence synthesis: levels of evidence adolescent OR male To help synthesise results from numerous studies on the v. Other team sport-related terms: Australian Rules same physiological construct, the “best evidence synthe- football OR American football OR Soccer. sis” was performed by the primary author (MC). The best evidence synthesis rating was determined based on Data extraction the number of studies that have investigated the meas- The selection process of the identified articles was con- urement property, the overall COSMIN score, and the ducted as described previously in stage 1. Subsequently, rating and consistency of the measurement property re- data extraction was conducted using two independent sult (positive, indeterminate, and negative) [87]. The people (SO and TM). All the data extracted was put on possible levels of evidence are “strong” (when consistent Microsoft Excel and was given to two other independent findings in multiple studies of good methodological assessors (JD and TM) for further verification purposes quality were found or in one excellent methodological on the accuracy of the data. The following data were quality study), “moderate” (when consistent findings in extracted: publication details (first author, year of publica- multiple studies of fair methodological quality were tion), title, purpose of the study, age of the participants, found or in one study of good methodological study), country, sport context, physiological construct evaluated, “limited” (if only one study of fair methodological quality test(s) used to measure the construct, and the measure- was found), “conflicting” (conflicting findings) and “un- ment properties assessed (reliability, validity and respon- known” (if only studies of poor methodological quality siveness). For the measurement properties, the following were found or no studies) [87]. data were extracted: type of reliability or validity, interval period for test-retest and inter-rater studies, sample size Results: Stage 2 and the results obtained for each physiological test. Characteristics of included studies Figure 2 shows a flow chart for the selection of the stud- Quality assessment of the clinimetric studies and ies. Of 824 studies identified from the electronic data- measurement properties bases, 20 met the inclusion criteria. The majority of the The Consensus-based Standards for the Selection of studies did not meet the inclusion criteria because they health Measurement Instruments (COSMIN) checklist did not report on measurement properties. The general was used to evaluate the methodological quality of the characteristics of the included studies and a summary of included studies. Briefly, the COSMIN evaluates nine the measurement properties evaluated in each study are measurement property items (internal consistency, reli- summarised in Table 5. The studies were conducted in ability, measurement error, content validity, construct Australia (n = 9), Denmark, Brazil, Belgium (n = 2), validity (i.e. structural validity, hypothesis testing, cross- Norway, Ireland, Iran, Italy and Croatia (n = 1). The age cultural validity), criterion validity and responsiveness) of the participants in the included studies ranged from (Table 4). It also provides standardised information for 12 to 36 years. evaluating the quality of each item based on design re- Out of the 63 tests identified in stage 1, 20 studies de- quirements and statistical methods [84, 85]. The COS- scribed the measurement properties of only 21 tests. MIN scoring system per measurement property is based The tests were the 5 m, 10 m, 20 m and 30 m Speed on a point rating scale (poor to excellent) and the overall tests (speed), 20 m Repeated-Sprint test (repeated sprint- rating for the methodological quality of each study is ob- ing ability), Repeated-Effort test (repeated effort ability), tained by taking the lowest score [83, 84]. three Repeated High-Intensity Exercise tests (repeated Two reviewers (JD and TM) with prior COSMIN ex- high-intensity exercise performance), Yo-Yo IRT1 and 2 perience evaluated the methodological quality of each (prolonged high-intensity running ability), T120 s (an- study included in Stage 2. It was pre-planned that dis- aerobic endurance), 505 test (agility), Modified 505 test agreements were resolved by discussion with the third (agility), L run (agility), Change of Direction Speed test person (CT) until a consensus was reached. In addition (agility), Sergeant Jump test (lower-body muscular to the methodological quality assessment with the COS- power), and three Bench Press Repetition-to-Fatigue MIN, the quality criteria for rating of measurement tests (upper-body strength-endurance). properties checklist as given by Terwee et al. [86] was Of the 21 tests, 18 were studied for their measurement used to rate each measurement property in the included properties in rugby. The Yo-Yo Intermittent Recovery articles as ‘positive’, ‘negative’ or ‘questionable’ depending Level 1 and 2 and the Sergeant Jump tests had their on the results of the property reported (Table 4). Studies measurement properties derived from other related with “poor” methodological qualities were not analysed sports (Soccer and Australian Rules football). Other than for the quality of the results on the measurement the tests mentioned above, there was no evidence on the properties. measurement properties either in rugby or related sports Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 20 of 38 Table 4 Rating of the Quality of the statistical outcomes to determine measurement properties Measurement property Definition (Rating) Quality criteriaa, b Reliability Internal consistency The extent to which items in a (sub)scale are (+) Factor analyses performed on adequate sample size intercorrelated, thus measuring the same (7 * # items and >100) AND Cronbach’s alpha(s) construct calculated per dimension AND Cronbach’s alpha(s) between 0.70 and 0.95; (?) No factor analysis OR doubtful design or method (−) Cronbach’s alpha(s) 0.70 or O0.95, despite adequate design and method. (0) No information found on internal consistency. Reproducibility Agreement The extent to which the scores on repeated (+) MIC < SDC OR MIC outside the LOA OR convincing measures are close to each other (absolute arguments that agreement is acceptable. measurement error) (?) Doubtful design or method OR (MIC not defined AND no convincing arguments that agreement is acceptable) (−) MIC > SDC OR MIC equals or inside LOA, despite adequate design and method; (0) No information found on agreement. Reliability The extent to which patients can be (+) ICC > 0.70 OR k > 0.70 distinguished from each other, despite (?) Doubtful design or method (e.g., time interval not measurement errors (relative measurement mentioned) error) (−) ICC or weighted Kappa ≤0.70, despite adequate design and method (0) No information on reliability found Validity Content Validity The extent to which the domain of interest is (+) A clear description is provided of the measurement comprehensively sampled by the items in the aim, the target population, the concepts that are being questionnaire measured, and the item selection AND target population and (investigators OR experts) were involved in item selection; (?) A clear description of above-mentioned aspects is lacking OR only target population involved OR doubtful design or method; (−) No target population involvement; (0) No information found on target population involvement. Construct validity The extent to which scores on a particular (+) Specific hypotheses were formulated AND at least questionnaire relate to other measures in a 75% of the results are in accordance with these manner that is consistent with theoretically hypotheses; derived hypotheses concerning the (?)Doubtful design or method (e.g., no hypotheses); concepts that are being measured (−) Less than 75% of hypotheses were confirmed, despite adequate design and methods; (0) No information found on construct validity. Criterion validity (predictive or concurrent The extent to which scores on a particular C(+) correlation with standard ≥0.70 OR no statistically questionnaire relate to a gold standard significant differences between the two tests found OR sensitivity and specificity ≥0.70 OR convincing arguments that gold standard is “gold” AND correlation with gold standard >0.70; (?)No convincing arguments that gold standard is “gold” OR doubtful design or method; (−) Correlation with standard <0.70 or AUC < 0.70 OR statistically significant differences between outcome measures and gold standard OR sensitivity or specificity <0.70 Responsiveness The ability of a questionnaire to detect (+) SDC or SDC 0.70; (?) Doubtful design or method; (−) SDC or SDC >MIC OR MIC equals or inside LOA OR RR < 1.96 OR AUC< 0.70, despite adequate design and methods. (0)No information found on responsiveness. Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 21 of 38 Table 4 Rating of the Quality of the statistical outcomes to determine measurement properties (Continued) Measurement property Definition (Rating) Quality criteriaa, b Floor and ceiling effects The number of respondents who achieved (+)≤ 15% of the respondents achieved the highest or the lowest or highest possible score lowest possible score (?) Doubtful design or method (−) > 15% achieved the highest and lowest possible score despite adequate designs and methods (0) No information found on interpretation Interpretability The degree to which one can assign (+) Mean and SD scores presented of at least four relevant qualitative meaning to quantitative scores subgroups of patients and MIC defined; (?) Doubtful design or method OR less than four sub groups OR no MIC defined; (0) No information found on interpretation. MIC minimal important change, SDC smallest detectable change, LOA limits of agreement, ICC Intraclass correlation, SD standard deviation a(+) positive rating; (?) indeterminate rating; (−) negative rating; (0) no information available bDoubtful design or method = lacking of a clear description of the design or methods of the study, or any important methodological weakness in the design or execution of the study for all the other tests identified in stage 1. However, Measurement properties and methodological quality for the 21 tests identified in stage 2, none of the tests assessments had all the measurement properties investigated. But, Tables 6 and 7 provide an overview of the measurement the majority of the studies (n = 7) investigated the re- properties for the identified physiological tests and the liability and validity of one or more physiological tests COSMIN rating of methodological quality for the [6, 19, 74, 88–91]. studies per measurement property. Table 8 shows rating Fig. 2 Flow chart for the search and selection of stage 2 articles Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 22 of 38 Table 5 Characteristics of included studies from stage 2 and the psychometric properties assessed Authors Title Purpose of the study Age Country Sport Test(s) Construct measured Properties evaluated Austin et al. Reliability and sensitivity of a To examine the reliability 24 ± 4 (Backs); 24 ± 3 Australia RL and RU RHIE Backs test Repeated high- Reliability (2013) [24] repeated high- intensity and sensitivity of 3 (RU forwards); 24 ± 2 RHIE RL Forward test intensity exercise exercise performance test for repeated high-intensity (RL forwards) RHIE RU Forward test Rugby league and Rugby exercise tests (RHIE) Union Baker (2009) Ability and validity of 3 To compare the ability Study 1 = 20.0 ± Australia RL BP RTF 60% 1RM Upper-body Validity [81] different methods of and validity of 3 different 1.2–24.9 ± 3.0 years BP RTF 60 kg strength-endurance assessing upper-body methods of assessing Study 2 = 19.5 ± BP RTF 102.5 kg strength-endurance to strength-endurance 1.7–25.0 ± 3.3 years distinguish playing rank in professional rugby league players Duthie et al. The reliability of ten-meter To compare the reliability 17 ± 0.7 years Australia RU 10 m sprint test with Speed Reliability (2006) [99] sprint time using different of 10 m sprint times foot start starting techniques when using different 10 m sprint test with starting techniques standing start 10 m sprint test with thumb start Gabbett et al. Speed, change of direction, To investigate the 23.6 ± 5.3 years Australia RL 5 m sprint test Speed, Agility Reliability, Validity (2008) [19] and reactive agility of discriminative ability of 10 m sprint test Rugby League players speed, change of 505 test direction speed, and Modified 505 test reactive agility tests Lrun test Green et al. A valid field test protocol To investigate the 19 ± 1.67–19 ± Ireland RU 10 m sprint test Speed, Agility Reliability, Validity (2011) [6] of linear speed and agility reliability and construct 1.30 years 30 m sprint test in Rugby Union validity of a field test Change of direction protocol speed Holloway et al. The Tripple-120 m shuttle To design a sport specific 21.5 ± 2.15 years Australia RL Tripple-120 m shuttle Anaerobic Validity (2008) [70] test: A sport-specific test for test for anaerobic test endurance assessing anaerobic fitness endurance and compare in Rugby League Players the validity of the test with the Wingate 60-s cycle test Johnston and Repeated-sprint and effort To assess the test-retest 22.7 ± 2.2 years Australia RL Repeated ability Repeated sprint Reliability Gabbett (2011) ability in Rugby League reliability of repeated sprint test ability and effort [51] players sprint and repeated Repeated effort test effort tests Serpell et al. The development of a new To develop a reliable >18 years Australia RL Change of direction Agility Reliability, Validity (2010) [74] test of agility for Rugby and valid agility test speed test League. Scott et al. Reliability and usefulness of Examined the reliability 15.6 ± 0.3–19.4 ± Australia RL 30–15 Intermittent Intermittent Reliability (2015) [68] the 30–15 Intermittent and usefulness of the 30 0.5 years fitness test running ability fitness test in Rugby League Intermittent Fitness test Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 23 of 38 Table 5 Characteristics of included studies from stage 2 and the psychometric properties assessed (Continued) Authors Title Purpose of the study Age Country Sport Test(s) Construct measured Properties evaluated Ingebrigtsen Yo-Yo IR2 testing of elite and To correlate the Yo-Yo 20 ± 3–26 ± 7 years Denmark and Soccer Yo-Yo intermittent Prolonged high- Validity et al. (2012) [97] sub-elite soccer players: Intermittent recovery Norway recovery test (level 2) intensity intermittent Performance, heart rate test level 2 with other running ability response and correlations to frequently used tests in other interval tests elite soccer Deprez et al. Reliability and validity of the To investigate the test- 12.5 ± 0.6–16.2 ± Belgium Soccer Yo-Yo intermittent Prolonged high-intensity Reliability, Validity (2014) [88] Yo-yo intermittent recovery retest reliability and 0.6 years recovery test (level 1) intermittent running test (level 1) in young soccer construct validity from ability players the Yo-Yo Intermittent recovery test level 1 Krustrup et al. The Yo-yo intermittent To examine the Range: 25–36 years Denmark Soccer Yo-yo intermittent Prolonged high-intensity Reliability, Validity (2003) [89] recovery test: Physiological reproducibility and recovery test (level 1) intermittent running response, reliability and validity of the Yo-Yo ability validity intermittent recovery test level 1 Krustrup et al. The Yo-Yo IR2 test: To examine the Range: 22–30 years Denmark Soccer Yo-yo intermittent Prolonged high-intensity Reliability (2006) [98] Physiological response, physiological response recovery test (level 2) intermittent running reliability and application to and reliability of the ability elite soccer Yo-Yo intermittent recovery test level 2 Markovic & Discriminative ability of the To evaluate the 12.0–18.9 years Croatia Soccer Yo-yo intermittent Prolonged high-intensity Validity Mikulic (2011) Yo-yo intermittent recovery discriminative ability of recovery test (level 1) intermittent running [93] test (level 1) in prospective the Yo-yo intermittent ability young soccer players recovery test level 1 Fanchini et al. Are the Yo-yo intermittent To compare the reliability, 17 ± 1 years Italy Soccer Yo-yo intermittent Prolonged high-intensity Reliability, Validity (2014) [94] recovery test levels 1 and 2 internal responsiveness recovery test (level 1) intermittent running Responsiveness both useful? Reliability, and interchangeability of Yo-yo intermittent ability responsiveness and the Yo-Yo intermittent recovery test (level 2) interchangeability in young recovery test level 1 soccer players Buchheit & The 30–15 Intermittent fitness To examine the 15.4 ± 0.5 years Iran Soccer Yo-yo intermittent Prolonged high-intensity Validity, Rabbani (2014) test versus the Yo-yo relationship between Yo- recovery test (level 1) intermittent running Responsiveness [95] intermittent recovery test level Yo intermittent recovery ability 1: relationship and sensitivity test and the 30–15 to training. Intermittent Fitness test and compare the sensitivity of both tests to training Deprez et al. The Yo-Yo intermittent To investigate the test- 13.9 ± 0.5–18.1 ± Belgium Soccer Yo-yo intermittent Prolonged high-intensity Reliability (2015) [96] recovery test level 1 is reliable retest reliability of the 0.4 years recovery test level 1 intermittent running in young high-level soccer Yo-yo intermittent ability players recovery test level 1 Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 24 of 38 Table 5 Characteristics of included studies from stage 2 and the psychometric properties assessed (Continued) Authors Title Purpose of the study Age Country Sport Test(s) Construct measured Properties evaluated Da Silva et al. Yo-Yo IR2 and Margaria test: To evaluate the reliability, 14 ± 0.8 years Brazil Soccer Yo-Yo intermittent Prolonged high-intensity Reliability, Validity (2011) [91] Validity, reliability and construct validity of the recovery test (level 2) intermittent running maximum heart rate in Yo-Yo intermittent ability young soccer players recovery test and of the Margaria test. De Salles et al. Validity and reproducibility To check the validity, 14.3 ± 0.66 years Brazil Soccer Sargent (vertical jump) Lower-body muscular Reliability, Validity (2012) [90] of the Sargent jump test in inter and intra-evaluators jump test power the assessment of explosive reproducibility of the strength in soccer players Sergeant jump test. Veale et al. The Yo-yo intermittent To evaluate the 16.6 ± 0.5 years Australia Australian Yo-Yo intermittent Prolonged high-intensity Validity (2010) [92] recovery test (level 1) to discriminative validity of football recovery test (level 1) intermittent running discriminate elite junior the Yo-yo intermittent ability Australian football players recovery test RU = Rugby union; RL = Rugby League; Bench Press repetition-to-fatigue with resistance at 60% 1RM = BP RTF 60% 1RM; Bench Press repetition-to-fatigue with resistance at 60 kg and 102.5 kg = BP RTF 60 kg and BP RTF 102.5 kg Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 25 of 38 Table 6 Measurement properties (reliability and measurement error) of the physiological tests and methodological quality scores Test Reliability (Intra-rater, inter-rater, test-retest) and measurement error COSMIN Design (interval period) n Results Score RHIE Backs test [24] Test-retest (2 days) 12 Total sprint time, ICC = 0.82 (CV = 0.1–3.2%); Poor Percentage decrement, ICC = 0.78 (CV = 4.2–49.5%) RHIE RL Forward test [24] Test-retest (2 days) 12 Total sprint time, ICC = 0.97 (CV = 0.1–4.9%); Poor Percentage decrement, ICC = 0.86 (CV = 1.4–48.2%) RHIE RU Forward test [24] Test-retest (2 days) 12 Total sprint time, ICC = 0.94 (CV = 0.1–5.1%); Poor Percentage decrement, ICC = 0.88 (CV = 0.6–35.8%) 5 m sprint [19] Test-retest (2 days) 42 Fastest time, ICC = 0.84 (% TE = 3.2) Fair 10 m sprint [19] Test-retest (2 days) 42 Fastest time, ICC = 0.87 (%TE = 1.9) Fair 10 m sprint with foot start [99] Test-retest (7 days) 15 ICC = 0.86 (TE% = 0.9) Poor 10 m sprint with standing start [99] Test-retest (7 days) 15 ICC = 0.92 (TE% = 0.88) 10 m sprint with thumb start Test-retest (7 days) 15 ICC = 0.92 (TE% = 1.00) 10 m sprint [6] Test-retest (3 days) 11 Average sprint time, ICC = 0.88 (SEM = 0.08) Poor 20 m sprint [19] Test-retest (2 days) 42 Fastest time, ICC = 0.96 (% TE = 1.3) Fair 30 m sprint [6] Test-retest (3 days) 11 Average sprint time, ICC = 0.97 (SEM = 0.06) Poor 505 test [19] Test-retest (2 days) 42 Fastest time, ICC = 0.90 (%TE = 1.9) Fair Modified 505 test [19] Test-retest (2 days) 42 Fastest time, ICC = 0.92 (%TE = 2.5) Fair L run test [19] Test-retest (2 days) 42 Fastest time, ICC = 0.95 (%TE = 2.8) Fair CODS test [6] Test-retest (3 days) 11 Average time, ICC = 0.87 (SEM = 0.06) Poor CODS test [74] Test-retest (7 days) 15 Average time, ICC = 0.87 (SEM = 0.01) Poor T120S test [70] Test-retest (4 days) 12 Total time taken, r = 0.74 (p = 0.006) Poor 20 m RSA test [51] Test-retest (7 days) 12 Total sprint time, ICC = 0.96 (%TE = 1.5) Poor Decrement (%), ICC = 0.91 (%TE = 22.5) Average heart rate, ICC = 0.56 (%TE = 3.5) Peak heart rate, ICC = 0.88 (%TE = 1.4) Rating of perceived exertion, ICC = 0.78 (%TE = 5.5) REA test [51] Test-retest (7 days) 12 Total time, ICC = 0.82 (%TE = 2.3) Poor Decrement (%), ICC = 0.91 (%TE = 6.7 Average heart rate, ICC = 0.96 (%TE = 0.9) Peak heart rate, ICC = 0.88 (%TE = 1.5) Rating of perceived exertion, ICC = 0.59 (%TE = 3.3) 30–15IFT test [68] Test-retest (9 days) 55 Maximal intermittent running velocity (VIFT), Good ICC = 0.89 (CV% = 1.9); SWC = 0.21 13 Heart rate, ICC = 0.96 (CV% = 0.6); SWC = 1 Poor beats per minute Yo-Yo IR1 [88] Test-retest (8 days) 35 Under 13: Total distance, ICC = 0.82 Poor (CV% = 17.3); LoA = 0.98 ×/÷ 1.27, range = 0.77–1.24 32 Under 15: Total distance, ICC = 0.85 (CV% = 16.7); LoA = 0.89 ×/÷1.30, range = 0.68–1.16 11 Under 17: Total distance, ICC = 0.94 (CV% = 7.9); LoA = 0.94 ×/÷ 1.15, range = 0.82–1.08 Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 26 of 38 Table 6 Measurement properties (reliability and measurement error) of the physiological tests and methodological quality scores (Continued) Test Reliability (Intra-rater, inter-rater, test-retest) and measurement error COSMIN Design (interval period) n Results Score Yo-Yo IR1 [89] Test-retest (within 1 week) 13 Total distance, r = 0.98 (CV% = 4.9) Poor Yo-Yo IR1 [94] Test-retest (7 days) 24 Total distance, ICC = 0.78 (CV = 7.3%) Poor Yo-Yo IR2 [94] Test-retest (7 days) 24 Total distance, ICC = 0.93 (CV = 7.1%) Poor Yo-Yo IR1 [96] Test-retest (3 measurements 22 Under 15: Total distance, ICC = 0.92 Poor within 1 week intervals) (CV% = 6.8–7.5); 95% ratio LoA (test 1 vs. test 2) =1.17 */÷ 1.24; 95% ratio LoA (test 2 vs. 3) = 0.96 */÷ 1.23; 95% ratio limit (test 1 vs. 3) = 1.13 */÷ 1.28. 10 Under 17: Total distance, ICC = 0.95 (CV% = 3.1–5.4); 95% ratio LOA (test 1 vs. test 2) = 1.09 */÷ 1.13; 95% ratio LoA (test 2 vs. 3) = 0.97 */÷ 1.09; 95% ratio LoA (test 1 vs. 3) = 1.06 */÷ 1.15. 4 Under 19: Total distance, ICC = 0.87 (CV% = 3.0–6.9); 95% ratio LoA (test 1 vs. test 2) = 1.02 */÷ 1.11; 95% ratio LoA (test 2 vs. 3) = 0.88 */÷ 1.12; 95% ratio LoA (test 1 vs 3) = 0.90 */÷ 1.22. Yo-Yo IR2 [98] Test-retest (2 days) 29 Total distance, CV% = 9.6%. Poor Yo-Yo IR2 [91] Test-retest (7 days) 18 Total distance, ICC = 0.38 (CV% = 11) Poor Vertical (Sargent) jump test [90] Intra-rater (testing sessions 45 ICC = 0.99 (95% CI = 0.99–1.00) Fair separated by 2 h) Inter-rater 45 ICC = 1.00 (95% CI = 0.99–1.00) Fair Sign diff = significant differences; b/w = between; CV% = Coefficient of Variation expressed as a percentage; CI = confidence interval; ICC = Intraclass correlation coefficient; r = Pearson correlation coefficient; * highest effect size calculated between groups; SWC = smallest worthwhile change;; IFT = Intermittent fitness test; TE% = Percent typical error of measurement; CODS = Change of direction speed; T120S = Tripple-120 m shuttle test; r = Pearson’s product moment correlations; RSA = repeated sprint ability; REA = repeated effort ability; SWC = smallest worthwhile change; 95% ratio LoA = limits of agreement; Yo-Yo IR1 and 2 = Yo-Yo intermittent recovery tests 1 and 2 of the quality of the results on the measurement proper- were rated “poor”. In all these studies, the sample size ties based on the quality rating criteria of measurement had the lowest score and therefore determined the total properties checklist given by Terwee et al. [86]. The score for the study. Another measurement property inves- results on the measurement properties for the physio- tigated for the Yo-Yo IR1 was responsiveness. However, logical tests derived from studies of “poor” methodo- responsiveness of the Yo-Yo IR1 test was reported in two logical quality were excluded from the rating. studies of “poor” methodological quality [94, 95]. Yo-Yo intermittent recovery level 1 (Yo-Yo IR1) test Yo-Yo intermittent recovery level 2 (Yo-Yo IR2) test Of the 20 studies included in the review, seven investi- Of the 20 studies included in the review, four studies gated at least one measurement property of the Yo-Yo provided evidence on at least one measurement property IR1 test (Table 5). Validity was the most commonly of the Yo-Yo IR2 test (Table 5) [91, 94, 97, 98]. Validity studied measurement property with six studies evaluat- and reliability were the most commonly studied meas- ing at least one type of validity [88, 89, 92–95]. There urement properties of the test [91, 94, 97, 98]. Three was evidence on known-group validity [88, 92, 93], studies evaluated the test-retest reliability of the Yo-Yo convergent [89, 94, 95] and criterion validity [89] of the IR2 with a seven day interval between the assessments Yo-Yo IR1 test. However, all the six studies were rated [91, 94, 98]. However, all the three studies were rated “poor” on methodological quality mainly because of the “poor” on methodological quality mainly because of small inadequate sample sizes used in the validity analysis. sample sizes used for the reliability analysis. On the other Reliability was the second most commonly studied hand, there were four studies that investigated the validity measurement property with four studies evaluating of the Yo-Yo IR2 test (Table 5) [91, 94, 97, 98]. Two stud- test-rest reliability (Table 5) [88, 89, 94, 96]. The test- ies provided evidence on convergent [94, 97] and criterion retest intervals ranged from within one week to eight [97, 98] validity of the Yo-Yo IR2 test. In addition, singular days [88, 89, 94, 96]. On methodological quality, all the studies investigated the known-group validity [97] and studies investigating the reliability of the Yo-Yo IR1 concurrent validity of the test [91]. All the studies were, Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 27 of 38 Table 7 Measurement properties (validity and responsiveness) of the physiological tests and methodological quality scores Test Validity COSMIN Responsiveness COSMIN Type n Results Score Design n Results Score BP RTF 60 [81] Hypothesis testing (Known 38 Sign diff b/w groups Fair – – – – group validity) NRL (36.1 ± 7.2) vs. SRL (28.0 ± 5.6) BP RTF 102.5 [81] Hypothesis testing (Known 38 Sign diff b/w groups Fair – – – – group validity) NRL (12.5 ± 4.3) vs. SRL (5.9 ± 3.9) BP RTF 60% 1RM [81] Hypothesis testing (Known 26 No sign diff b/w NRL and SRL players Poor – – – – group validity) 5 m sprint test [19] Hypothesis testing (Known 42 Sign diff b/w groups (First grade RL Fair – – – – group validity) players vs. Second grade RL players) Effect Size = 0.68 10 m sprint test [19] Hypothesis testing (Known 42 Sign diff b/w groups (First grade RL Fair – – – – group validity) players vs. second grade RL players) Effect size = 0.85 10 m sprint test [6] Hypothesis testing (Known 28 Sign diff b/w (Club RU players vs. Poor – – – – group validity) Academy RU players) Effect size = 2.86 30 m sprint test [6] Hypothesis testing (Known 28 Sign diff b/w (club RU players vs. Poor – – – – group validity) Academy RU players) Effect size = 1.61 505 test [19] Hypothesis testing (Known 42 No sign diff b/w between groups Fair – – – – group validity) Effect size = 0.28 Modified 505 test [19] Hypothesis testing (Known 42 No sign diff b/w groups Fair – – – – group validity) Effect size = 0.32 L run [19] Hypothesis testing (Known 42 No sign diff b/w groups Fair – – – – group validity) Effect size = 0.28 CODS test [6] Hypothesis testing (Known 28 Sign diff b/w groups. Effect size = 2.23 Poor – – – – group validity) CODS test [74] Hypothesis testing (Known 30 No sign diff b/w groups (Low Poor – – – – group validity) performance group, n = 15 vs. High performance group, n = 15) T120S test [70] Criterion validity 12 Sign corr in maximum heart rate b/w Poor – – – – the 2 trials of T120S and W60 cycle test (r = 0.63 and 0.71). No sign corr b/w 2 trials of T120S and W60 cycle test for post 3 min lactate (r = 0.11 and 0.10). Yo-Yo IR2 [97] Hypothesis testing (Known 51 Sign diff b/w elite vs. sub-elite soccer Poor – – – – group validity) players. Hypothesis testing 12 Sign corr b/w Yo-Yo IR2 and Yo-Yo IR1 Poor (convergent validity) 39 (r = 0.74, p < 0.01) for the elite players. Sign corr b/w Yo-Yo IR2 and Yo-Yo IR1 (r = 0.76, p < 0.01) for sub-elite players. Hypothesis testing 12 Poor (convergent validity) 39 Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 28 of 38 Table 7 Measurement properties (validity and responsiveness) of the physiological tests and methodological quality scores (Continued) Test Validity COSMIN Responsiveness COSMIN Type n Results Score Design n Results Score Sign corr b/w Yo-Yo IR2 and 35 m repeated sprint ability test (r = −0.74, p < 0.01) for elite players. Moderate corr observed for sub-elite (r = −0.34, p < 0.05) Criterion validity 13 Moderate corr for sub-elite players b/w Poor 12 Yo-Yo IR2 and treadmill test (r = 0.48, p < 0.01). No significant corr for the elite players (r = 0.59, p < 0.10) Yo-Yo IR1 [97] Hypothesis testing (Known 51 Sign diff b/w elite (n = 12) vs. sub-elite Poor – – – – group validity) (n = 39) soccer players Hypothesis testing 12 Very large corr b/w Yo-Yo IR1 and Poor (convergent validity) 39 35 m repeated sprint time (r = −0.80, p < 0.01) for elite players (n = 12). Large corr b/w Yo-Yo IR1 and 35 m repeated sprint time (r = −0.51, p < 0.05) for sub-elite players (n = 39) Criterion validity 12 Very large corr. b/w Yo-Yo IR1 and Poor 39 VO2MAX for elite players (r = 0.76, p < 0.01). Very large corr b/w Yo-Yo IR1 and VO2MAX for sub-elite players (r = 0.73, p < 0.01). Yo-yo IRT1 [92] Hypotheses testing 60 Sign diff b/w groups (P < 0.001). Poor – – – – (Known group validity) *ES = 3.78 elite Australian rules football (n = 20) vs. healthy group (n = 20). Yo-yo IRT1 [88] Hypotheses testing (Known 208 Sign diff b/w groups (p < 0.001) Poor – – – – group validity) ES = 0.94 (90% CI = 0.46–1.43) b/w U15 Elite vs. Sub-elite Yo-yo IRT1 [89] Hypotheses testing 22 Sign corr b/w Poor Repeated measures, 4 testing sessions 10 Sign diff in Yo-yo mean distance Poor (Convergent validity) Yo-yo test performances and fitness [pre-preparation, mid preparation, start covered between preseason performances during soccer match season, end season] measures and seasonal measures assessed using time motion analysis (p < 0.05) (r = 0.53–0.71, p < 0.05) Sign diff in heart rate measures b/w preseason and seasonal measures (p < 0.05) Criterion validity 17 Sign corr b/w Yo-yo test performances and time to fatigue (r = 0.79, p < 0.05) and maximal oxygen uptake (r = 0.71, p < 0.05) Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 29 of 38 Table 7 Measurement properties (validity and responsiveness) of the physiological tests and methodological quality scores (Continued) Test Validity COSMIN Responsiveness COSMIN Type n Results Score Design n Results Score Yo-Yo IRT1 [93] Hypotheses testing (Known 106 Sign group differences in YY IRT1 Poor – – – – group validity) among age categories (F = 25.3; p < 0.001). *ES = 4.17 (U 13 vs. U 19) p < 0.01 Yo-Yo IRT1 [94] Hypotheses testing 24 Sign corr b/w Yo-Yo IRT1 and Yo-Yo – Repeated measures 24 ES = 0.9 (90%CI = 0.66–1.18); Poor (Convergent validity) IRT2 (r = 0.56–0.84) [(3 testing sessions of Yo-yo IRT1 before SWC = 3.7%; 11 wks of training + matches and 2 MDC = 20.2%; testing sessions post training + % changes after training = 14.5%; matches] Probability of substantial changes btwn pre-and post-measures = 99.9% Yo-Yo IRT2 [94] Hypotheses testing 24 Sign corr b/w Yo-Yo IRT1 and Yo-Yo poor Repeated measures 24 ES = 0.4 (90%CI = 0.17–0.69); (Convergent validity) IRT2 (r = 0.56–0.84). [(3 testing sessions of Yo-yo IRT2 before SWC = 4.8%; 11 wks of training + matches and 2 MDC = 19.5%; testing sessions post training + matches] Yo-Yo IR1 [95] Hypotheses testing 14 Large corr b/n Yo-yo IRT1 and 30–15 Poor Pre and post measures interspaced by 14 Within-test % changes = +35% Poor (Convergent validity) IFT (r = 0.75, 90%CI = 0.57–0.86) an 8-week training intervention (90% CI = 24–45) for Yo-yo IRT1 vs. +7% (90% CI = 4–10) for 30–15 IFT ES for the changes (standardised differences): Yo-yo IRT1 = 1.2 vs. 1.1 for 30–15 IFT Yo-Yo IRT2 [98] Criterion validity 13 A sign corr b/w Yo-yo IR2 and time to Poor fatigue in the incremental running test (r = 0.74, p < 0.05) Yo-Yo IRT2 [91] Hypotheses testing 18 High positive corr found b/w Yo-Yo Poor – – – (Concurrent validity) IRT2 and PRT >85% MHR during the match (r = 0.71, p = 0.001) Vertical (Sargent) jump Criterion validity 45 ICC = 0.99 (95% CI = 0.97–1.00) p = 0.001 Fair – – – test [90] PRT performance of time of remaining above 85% MHR in the game, Yo-Yo IR1 and 2 Yo-Yo intermittent recovery test level 1 and 2, T120S Triple 120 m shuttle run test, CODS Change of direction speed test, ES effect size, SWC smallest worthwhile change, MDC minimal detectable change, 30–15 IFT 30–15 Intermittent fitness test, BP RTF bench press repetitions to fatigue test Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 30 of 38 Table 8 Overall quality score by study and rating of measurement properties for the physiological tests Test Reliability Construct validity Criterion Responsiveness Interpretability Intra Inter Test- retest Known group Convergent/Concurrent BP RTF 60 [81] 0 0 0 + 0 0 0 0 BP RTF 102.5 [81] 0 0 0 + 0 0 0 0 30–15IFT [68] 0 0 + 0 0 0 0 0 5 m sprint test [19] 0 0 + + 0 0 0 0 10 m sprint test [19] 0 0 + + 0 0 0 0 20 m sprint test [19] 0 0 + + 0 0 0 0 505 test [19] 0 0 + – 0 0 0 0 Modified 505 test [19] 0 0 + – 0 0 0 0 Lrun test [19] 0 0 + – 0 0 0 0 Sargent (vertical) jump test [90] + + 0 0 0 ? 0 0 ? = doubtful design or method; 0 = no information; + = positive rating; − = negative rating; criterion = criterion validity however, rated “poor” on methodological quality. Respon- the 10 m sprint test. There was no evidence found siveness of the Yo-Yo IR2 test was examined in one study on the responsiveness of the test. of “poor” methodological quality [94]. 20 m sprint test Only one “fair” study investigated the Speed tests measurement properties (reliability and validity) of the 20 m sprint test (Table 5) [19]. The 20 m sprint 5 m sprint test Only one “fair” study investigated the test was found to have positive rating for the test- measurement properties (reliability and validity) of retest reliability (Tables 6 and 8) [19]. The same study the 5 m sprint test (Table 5) [19]. The 5 m sprint test provided evidence on the construct validity of the test was found to have positive rating [i.e. Intraclass (Table 7). A positive rating for the known-group Correlation Coefficient (ICC) > 0.70] for the test-retest validity was found for the 20 m sprint test as specific reliability (Tables 6 and 8) [19]. The same study pro- hypotheses were formulated and at least 75% of the vided evidence on the construct validity of the test results were in accordance with these hypotheses (Table 7). A positive rating for the known-group (Table 8). There was no evidence on the responsive- validity was found for the 5 m sprint test as specific ness for the test. hypotheses were formulated and at least 75% of the results were in accordance with these hypotheses (Table 8). There was no evidence on the responsive- 30 m sprint test Test-retest reliability evidence of the ness found for the test. 30 m sprint test was provided by one study rated “poor” on methodological quality [6]. The study used a sample size of 11 participants to establish the reliability of the 10 m sprint test Three different studies investigated test with three days between the test-retest assessments. the measurement properties of the 10 m sprint test In the same study, the 30 m sprint test was also assessed (Table 5) [6, 19, 55]. Reliability was the most com- for its known-group validity [6]. However, the study was monly studied measurement property. All the three also rated “poor” on quality for the construct validity. studies had test-retest reliability evidence for the There was no evidence found on the responsiveness of 10 m sprint test, with an interval of two to seven the test. days between the assessments [6, 19, 99]. However, two of the studies were rated “poor” on methodo- logical quality [6, 99]. In one “fair” study, a positive Repeated-sprint ability (RSA) test rating for the test-retest reliability (ICC = 0.87) of the One study assessed the test-retest reliability of re- 10 m sprint test was found [19]. Validity of the 10 m peated sprint ability test with assessments being sprint test was assessed in two studies [6, 19]. The conducted after seven days (Tables 5 and 6) [51]. The most common type of validity studied was construct study was rated of “poor” methodological quality validity (known-group validity). One study was rated mainly because of small sample size used in the reli- as “poor” on methodological quality [6]. In that study, ability analysis. There was no evidence on validity or a positive rating of construct validity was found for responsiveness found for the test. Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 31 of 38 Repeated-effort ability (REA) test between groups on the performance of the test. No in- One study assessed the test-retest reliability of repeated- formation on responsiveness was found for the test. effort ability test with assessments being conducted after seven days [51]. The study was rated of “poor” methodo- Modified 505 test Reliability of the Modified 505 test logical quality mainly because of small sample size used was investigated in one study [19]. The study was “fair” in the reliability analysis. There was no evidence on on methodological quality because of the large sample validity found for the test. size. A positive rating (ICC = 0.92) on the test-retest reli- ability was found for the test. The same study investi- Repeated high-intensity exercise (RHIE) tests gated the construct validity of the test. The study had One study evaluated the test-retest reliability of three “fair” methodological quality on validity. A negative different repeated high-intensity exercise tests, namely, rating of construct validity (known-group validity) was the repeated high-intensity exercise backs test, repeated found for the Modified 505 test as there was no signifi- high-intensity exercise rugby union forward test, and the cant difference between groups (ES = 0.32). Therefore, repeated high-intensity exercise rugby league forward less than 75% of the results were in accordance with the test [24]. The quality of the study was, however, rated hypotheses. No information was found for the respon- “poor” mainly because of the small sample size per siveness of the test. reliability analysis utilised for each test. There was no in- formation on the validity or responsiveness of any of these tests in the literature. L run test One study examined both the test-retest reli- ability (over two days) and the construct validity of the L 30–15 intermittent fitness test (30–15 IFT) run [19]. The study was rated “fair” on methodological One study assessed the test-retest reliability of the 30– quality and a positive rating (ICC = 0.95) was reported 15 Intermittent Fitness test with nine days separating for the test-retest reliability. For the construct validity, a the two assessments [68]. For the measure of reliability negative rating was found for the L- run test as the re- for the primary outcome of maximal intermittent sults of the test showed an unexpected marginal effect running velocity (VIFT), the study was rated as of “good” size (ES = 0.28). There was no information found on methodological quality. A positive rating (ICC = 0.89) for responsiveness of the test. the test-retest reliability was reported for the test. Validity of the test was assessed in one study (Tables 5 Change of direction speed test Two studies reported and 7) [95]. The study was, however, rated “poor” on on the reliability of the change of direction speed test quality for the convergent validity of the 30–15 Inter- [6, 74]. The test-retest interval ranged between three mittent Fitness test [95]. to seven days. The same studies provided evidence on the construct validity (known-group validity) of the Triple 120-m shuttle test (T120S) test [6, 74]. However, the two studies were rated One study examined the test-retest reliability of the “poor” on methodological quality for both reliability Triple 120 m shuttle test for anaerobic endurance using and validity. There was no information found on a four day interval between assessments [70]. On the responsiveness of the test. other hand, the same study evaluated the criterion valid- ity of the test against the Wingate 60s (W60) cycle test. The study used a small sample size of 12 rugby league Sergeant (vertical) jump test players both for the reliability and the validity study and For the Sargent Jump test, there was only one study was rated “poor” on methodological quality. No informa- which was found evaluating inter and intra-rater reliabil- tion was found on the responsiveness of the test. ity of the test [90]. Intra-rater reliability was assessed with testing sessions separated by two hours whilst Agility/change of direction speed tests inter-rater reliability assessments were separated by two days. The study was rated “fair” on methodological 505 test One study examined both test-retest reliability quality. A positive rating for intra-reliability (ICC = 0.99) (over two days) and the construct validity of the 505 test and inter-rater reliability (ICC = 1.00) was reported for [19]. The study was rated “fair” on methodological qual- the test. The same study evaluated the validity of the ity and a positive rating (ICC = 0.90) was reported for Sergeant Jump test and showed positive criterion validity the test-retest reliability. For the construct validity, a against the Jump Platform (JP) test using 45 soccer par- negative rating was found for the 505 test as the results ticipants. The study was rated “fair” quality for criterion of the test showed an unexpected marginal effect size validity. There was no information found on responsive- (ES = 0.28) because there were no significant difference ness of the test. Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 32 of 38 Bench press repetitions-to-fatigue tests unknown evidence available on the measurement prop- One study examined the construct validity of three dif- erties of all the other tests identified in stage 1. ferent upper-body strength-endurance tests, namely, bench press repetitions-to-fatigue at 60% of one repeti- Discussion tion maximum test (BP RTF 60% 1RM), bench press The aim of the present systematic review was two-fold. repetitions-to-fatigue at 60 kg (BP RTF 60) and bench Firstly, we systematically reviewed 70 studies in Stage 1 press repetitions-to-fatigue at 102.5 kg (BP RTF 102.5) to identify physiological characteristics evaluated in [81]. For the BP RTF 60 and 102.5, the study was rated rugby and the corresponding tests used to measure each “fair” on methodological quality because of the adequate construct. Thereafter, 20 studies were systematically sample size (n = 38). A positive rating of construct reviewed in Stage 2 to provide an overview on the meas- validity was found for the two tests. However, for the urement properties of the physiological tests identified construct validity of the BP RTF 60% 1RM test, the in the studies. Most of the included studies from stage 1 study was rated “poor”. There was no information on were from Australia, United Kingdom, New Zealand, the reliability or responsiveness of the three tests in and South Africa. This probably reflects the popularity measuring upper body strength-endurance. of the sport of rugby in these respective countries. The fact that there were an almost equal number of adult Best evidence synthesis: level of evidence and adolescent rugby studies indicates that rugby is ex- A summary of best evidence synthesis are presented in tensively studied in junior and senior players. It is also Table 9. The synthesis was derived from information on possible to speculate that the sport is equally popular the rating of the methodological qualities of the studies among junior and senior players. and results on the measurement properties of the tests. One most important finding that emerged from stage Only studies with “fair” to “good” methodological quality 1 was that there are a number of physiological character- were used to determine the level of evidence per test for istics that are commonly investigated among rugby each studied measurement property. Best evidence players. Fifteen physiological characteristics were identi- synthesis showed moderate evidence to support the test- fied. This extensiveness probably confirms wide interest retest reliability of the 30–15IFT test. Limited evidence researchers have in physiological characteristics. The was found to support the test-retest reliability and the interest could be linked with suggestions that success in known-group validity of the 5 m sprint test, 10 m speed rugby is highly dependent on physiological characteris- test, 20 m speed test, 505 test, modified 505 test and the tics [75]. With increased professionalism and competi- Lrun tests. There is also limited level of evidence for in- tion, there has been extensive investment in research ter/intra-rater reliability and criterion validity of the towards establishing physical qualities important for suc- Sergeant (vertical) jump test. Furthermore, there was cessful performance in professional rugby. Moreover, limited evidence on the known group validity of the this breadth of physiological characteristics under inves- upper-body strength endurance tests of Bench-Press tigation potentially highlights the physical nature of the repetitions-to-fatigue at 60 and 102.5 kgs. There is sport and diversity in attributes needed to meet the Table 9 Best level synthesis for the physiological tests Test Reliability Hypothesis testing Inter Intra Test-retest Known group Convergent Criterion Responsiveness 5 m sprint test [19] 0 0 + + 0 0 0 10 m sprint test [19] 0 0 + + 0 0 0 20 m sprint test [19] 0 0 + + 0 0 0 505 test [19] 0 0 + 0 0 0 0 Modified 505 [19] 0 0 + 0 0 0 0 Lrun [19] 0 0 + 0 0 0 0 Sargent jump test [90] + + 0 0 0 + 0 BP RTF 60 [81] 0 0 0 + 0 0 0 BP RTF 102.5 [81] 0 0 0 + 0 0 0 30–15IFT [68] 0 0 ++ 0 0 0 0 +/− = limited evidence (One study of fair methodological quality); ++/−− moderate evidence (consistent findings in multiple studies of fair methodological quality OR in one study of good methodological quality; 0 = no evidence or information available. All the other tests had unknown level of evidence on measurement properties because of poor methodological quality Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 33 of 38 physical demands of the game. It is well-established that Although there could be plenty of reasons researchers rugby is a physical sport requiring participants to prefer a specific test over others, literature generally rec- partake in challenging physical collisions such as scrum- ommends the use of feasible, reliable, valid and respon- maging, tackling, aggressive mauling and rucking which re- sive tests [102]. This review found that there is dearth of quire optimal muscular strength, power and endurance [5]. high-quality studies (according to the COSMIN scoring This gives rationale to the preponderance of studies inves- system) investigating the measurement properties of tigating lower and upper body muscular power [15, 16, speed tests using rugby participants. Best evidence syn- 30–36, 40, 49, 61, 64, 73], lower and upper body muscular thesis only showed that there is limited evidence for the strength [5, 7, 18, 27, 38, 42, 55, 56, 69, 78, 80] and muscu- test-retest reliability and the known-group validity of the lar endurance [7, 15, 36, 81]. In addition, rugby players 5 m sprint test, 10 m sprint test and the 20 m speed test. variably cover 5000 to 7000 m during match play and en- Repeated-sprint ability has also been reported to be gage intermittently in high-intensity efforts which require extremely important in rugby given the high-intense exceptional agility, anaerobic and aerobic capacity, speed, and intermittent nature of the sport [100]. This re- repeated sprinting and effort ability and generation of high view showed that the construct is commonly mea- levels of concentric and eccentric force production [53, 75]. sured using the Repeated 20 m sprint test and the This also provides justification for numerous studies in- Rugby-Specific Repeated Speed test. There were no vestigating attributes such as speed, agility, prolonged high-quality studies found investigating the measure- high-intensity intermittent running ability, repeated sprint ment properties of these tests in rugby. Only one ability and explosive lower leg power [7, 16, 19, 30–38, 40, study of “poor” methodological quality was found 49, 51, 53, 70, 72, 76]. evaluating the test-retest reliability of the repeated Stage 1 findings also showed that almost all physio- 20 m sprint test using 12 rugby participants [51]. logical characteristics had multiple tests for measure- One needs to apply caution when adopting or using ment. For example, this review showed that change of these tests in future studies using rugby players. direction speed/agility is often evaluated using the 505, High-quality future studies may need to explore the modified 505, Illinois Agility test, change of direction measurement properties of these tests. Repeated- speed test among other tests. However, it was surprising sprint ability tests have been reported to underesti- to discover that for all the tests identified in Stage 1, mate the repeated high-intensity exercise demands of none had all the measurement properties (reliability, rugby [24]. To overcome the shortcomings of the re- validity and responsiveness) investigated using rugby peated 20 m sprint test, Austin et al. [24] assessed participants. In addition, of the 63 tests identified in the reliability of three repeated high-intensity exercise Stage 1, only 21 had information on at least one of the tests specifically developed for backline players, RU measurement properties from rugby and related sports. forward players and RL forward players. The study This suggests that there is limited reporting of the meas- was, however, rated as of “poor” methodological qual- urement properties for tests commonly used in rugby in ity because of the small sample size per reliability the literature. This was particularly evident for the prop- analysis of each test and short interval (2 days) for erty of responsiveness. All these findings are interesting the test-retest assessments. and raise questions on the rationale for selection of tests There is dearth of high-quality studies investigating by researchers in the field of rugby. For example, speed the measurement properties of the Yo-Yo intermittent was the most commonly studied physiological character- recovery (Level 1 and 2) tests in rugby. This is despite istic in the included studies. It was frequently measured the popularity of the tests in assessing prolonged high- from linear distances varying between 5 m and 60 m intensity intermittent running ability/endurance and (Table 2). The commonly tested sprinting distances for maximal aerobic power among rugby players [15, 24, speed were, however, the 10 m, 20 m and 40 m. Profes- 53–56, 69]. This creates a need for future studies to spe- sional rugby studies have provided the evidence that cifically evaluate the measurement properties of the test players seldom sprint distances greater than 40 m in a using rugby participants. However, much of the informa- single bout [100]. This probably justifies the predomin- tion on measurement properties of these tests reported ance use of the 10 m, 20 m and 40 m sprint tests in in rugby studies is referenced from validation studies assessing rugby players in the literature [30–40]. In conducted using participants from other sports. There addition, straight-line sprinting is reported to be broken are multiple studies providing the evidence of the meas- down into three phases: acceleration, attainment of max- urement properties (reliability, validity and responsive- imal speed, and maintenance of maximal speed [101]. ness) of the tests in other related intermittent sports such This is also possibly justifies the use of more than one as Soccer and Australian Rules football [88, 89, 91–98]. sprinting distance for assessing speed as all these distinct However, no high-quality studies were found evaluating qualities of speed should be evaluated separately. the measurement properties of the test according to the Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 34 of 38 COSMIN guidelines. All the studies included in this Lower-body muscular power was the second most review assessing the measurement properties of the commonly studied physiological characteristic among tests showed “poor” methodological quality. The major rugby players in the studies included in this review. Al- drawbacks in all these studies were mainly related to though, there were three tests identified estimating the the issues of inadequate sample sizes and lack of a clear lower-body muscular power in the included studies. We description of the expected hypotheses. There were also found no studies evaluating the measurement properties no studies evaluating the measurement properties of of all three tests in rugby. Evidence on the measurement other tests of prolonged high-intensity intermittent properties were found in one “fair” study evaluating the running ability such as the repeated 12 s sprint shuttle intra/inter-reliability and criterion validity of the Vertical speed tests. Jump test among soccer players. A positive rating was There were four tests identified estimating maximal found for the intra/inter-reliability of the test. Evidence aerobic power of rugby players: Multistage fitness, on criterion validity was found to be questionable Yo-Yo intermittent recovery level 1 test, 30–15 inter- (Table 8) as there was no convincing argument that the mittent fitness (30–15IFT) and the 1500 m run. The gold standard test used was “gold”. Overall, best evi- multistage fitness was commonly used in a number of dence synthesis indicates limited level of evidence for studies [7, 8, 10, 16, 27, 30–37, 40, 49, 50, 61–64]. the inter/intra-rater reliability and criterion validity of However, there is paucity of information on the meas- the Sergeant (vertical) jump test. urement properties for maximal aerobic power in There were also no clinimetric studies found testing rugby or related sports. Only one study of “good” the measurement properties of tests for lower-body methodological quality assessed the reliability and the muscular strength, upper-body muscular strength and usefulness of the 30–15 intermittent fitness in rugby power. However, one study of fair methodology provided participants [68]. Best evidence synthesis showed the evidence on the known-group validity of two tests moderate evidence to support the test-retest reliability of upper-body muscular endurance (bench press- of the 30–15 Intermittent Fitness test. There were no repetitions-to-fatigue test at 60 kg and 102.5 kg). Best high-quality studies providing evidence on the meas- evidence synthesis indicates that there is limited urement properties of tests identified for measuring evidence to support the validity of these two tests in anaerobic endurance such as the T120 s, Wingate evaluating upper-body strength-endurance. 60 cycle, 300 m Shuttle Run and the 400 m Sprint tests. Holloway et al. [70] evaluated the validity of the Limitations T120 s test and compared the validity of the test to The results of this review paper should be interpreted the Wingate 60 cycle test. According to the COSMIN with the understanding of a number of important limita- guidelines, the study was rated as of “poor” methodo- tions. Currently, there are no published reviews investi- logical quality as the study had 12 participants. gating measurement properties of performance-based There were number of studies that evaluated agility/ tests measuring physiological characteristics in rugby. change of direction speed of rugby players. There tests This renders comparisons with other review studies im- commonly used included: 505 test, Modified 505 test, possible. However, it suffices to suggest that these results Illinois Agility test, Change of Direction Speed test and expose a research gap on high-quality studies evaluating Agility test [6, 16, 19, 32, 34, 35, 40, 53, 74, 77]. There measurement properties for physiological tests com- were no high-quality studies evaluating the measure- monly used in rugby. Although it could also be a major ment properties of these tests in rugby. This is despite strength for this review, the inclusion criteria only con- the importance of agility as a physiological skill in the sidered full-text peer reviewed articles and completely sport of rugby. There was only one study of “fair” excluded grey literature. This publication bias likely methodological quality according to the COSMIN guide- threatens internal validity of results obtained on meas- lines that evaluated the measurement properties of the urement properties for this review as unpublished 505 test, modified 505 test, and the L run test. The study studies are more likely to report negative or unfavour- showed positive rating for the test-retest reliability of able results. Although the COSMIN has been developed these three agility tests. However, there was negative for the evaluation of measurement properties and has rating for the known group validity for these tests. These been generally used in the literature for that purpose, findings support best evidence synthesis results indicat- the guidelines appear well-suited and more applicable ing that there is limited evidence on the reliability and for appraising the quality of questionnaire-based studies. construct validity of these tests in assessing agility of In the context of performance-based tests such as used rugby players. There is still need for further high-quality in rugby, the applicability of the COSMIN as a quality studies evaluating the measurement properties of these rating tool for the studies on measurement properties tests in rugby players. still requires careful consideration. Chiwaridzo et al. BMC Sports Science, Medicine and Rehabilitation (2017) 9:24 Page 35 of 38 Conclusion Acknowledgements This review identified 15 physiological characteristics This systematic review is part of the lead author’s PhD work at University of Cape Town. Although, there was no external funding of this systematic commonly evaluated among rugby players. These review protocol per se, the primary investigator acknowledges the Vice include speed, repeated sprint and effort ability, repeated Chancellor of the University of Zimbabwe, Professor Levi Nyagura and the high-intensity exercise performance, prolonged high- Dean of the College of Health Sciences, Professor Midion Chidzonga for the support in sourcing financial support for the whole PhD work. In addition, intensity intermittent running ability, endurance, the primary investigator is indebted to Mrs. Morgan from the University of anaerobic endurance, maximal aerobic power and speed, Cape Town library for her help. agility, lower-body muscular power and strength, upper- body muscular strength and power and upper-body Funding muscular endurance. The majority of these physiological There was no funding for the systematic review. characteristics had multiple tests for measurement. Availability of data and materials Overall, there is paucity of high-quality clinimetric The data will not be shared since it forms part of ongoing research. studies evaluating measurement properties of commonly-used physiological tests in rugby. For those Authors’ contributions tests that had evidence on measurement properties, MC and BE conceptualised the idea of writing the systematic review. MC drafted there was no test which was evaluated with respect to all the manuscript in preparation for publication. SO reviewed search results for stage 1 and also conducted data extraction for stage 2. EB reviewed search results for measurement properties. More studies are required stage 1 as an independent reviewer. JD reviewed search results in cases of evaluating the measurement properties of the physio- agreements for stage 1, performed data extraction for stage 2 and assisted with logical tests commonly used in the sport of rugby. The the methodological rating of the studies. TM performed data extraction for stage 1 and assisted with the methodological rating of the studies. CT independently 30–15 intermittent fitness test (30–15IFT) test was the reviewed data extracted for stage 2. GF acted as a supervisor for the project, read best rated test on maximal aerobic power with moderate and edited the manuscript for submission to journal. BE also acted in supervisory evidence supporting its test-retest reliability. The 5 m, capacity, read and edited all drafted manuscripts. All authors read and approved the final version of the manuscript. 10 m and 20 m speed test were the best tests assessing speed, however, with limited evidence supporting their Authors’ information test-retest reliability and the known-group validity. The MC is a registered second year doctoral student at the University of Cape Town. BE 505 test, Modified 505 test and Lrun tests were the best is the overall supervisor of the doctoral thesis. GF is a senior physiotherapy lecturer at the University of Cape Town and acting in the capacity of a co-supervisor. JD tests for measuring agility but with limited evidence and CT are senior physiotherapists at the University of Zimbabwe. TM is a senior supporting their test-retest reliability. The Vertical jump physiotherapist at Harare Central Hospital. EB is a physiotherapist from Ghana. SO is test was the best test for assessing lower-body muscular a recent graduate of Human Movement from the University of Maastricht in Netherlands. power, however, with limited level of evidence for inter- rater, intra-rater reliability and criterion validity. Further- Ethics approval and consent to participate more, there is limited evidence on the known group This study was conducted as systematic review, so no ethical approval was validity of the upper-body strength endurance tests of sought and there was no need for informed consents. However, the review Bench-Press repetitions-to-fatigue at 60 and 102.5 kgs. forms part of a doctoral study registered under the University of Cape Town Human Research Ethics Committee (HREC 016/2016). Additional files Consent for publication Not applicable. Additional file 1: Stage 1 search strategy designed for Medline via PubMed. (DOCX 14 kb) Competing interests Additional file 2: Stage 2 search strategy designed for Medline via The authors declare that they have no competing interests. PubMed. (DOCX 14 kb) Publisher’s Note Abbreviations Springer Nature remains neutral with regard to jurisdictional claims in 1RM: One repetition maximum; 30–15IFT: 30–15 intermittent fitness test; published maps and institutional affiliations. AFL: Australian Rules Football; CI: Confidence interval; CINAHL: Cumulative Index of Nursing and Allied Health; CMJ: Countermovement jump; CODS: Change of Author details direction speed; COSMIN: Consensus-based Standards for the Selection of 1Department of Health and Rehabilitation Sciences, Division of health Measurement Instruments; CV: Coefficient of variation; ES: Effect size; Physiotherapy, Faculty of Health Sciences, University of Cape Town, Cape GPS: Global positioning system; HIEP: High intensity exercise performance; Town, South Africa. 2Department of Human Movement Sciences, Univeristy HIRA: High intensity running ability; HREC: Human Research Ethics Committee; of Maastricht, Faculty of Health, Medicine and Life Sciences, Maastricht, ICC: Intraclass correlation coefficient; JS: Jump squat; MSF: Multistage fitness test; Netherlands. 3Rehabilitation Department, University of Zimbabwe, College of PRISMA: Preferred reporting items for systematic reviews and meta-analyses; Health Sciences, P.O Box A178, Avondale, Harare, Zimbabwe. 4Department of RHIE: Repeated high intensity exercise; RL: Rugby league; RS2: Rugby specific Physiotherapy, University of Ghana, College of Health Sciences, School of repeated sprint test; RU: Rugby union; SEM: Standard error of measurement; Biomedical and Allied Health Sciences, Accra, Ghana. 5Harare Central T120S: Triple 120 m shuttle run test; TE%: Percent typical error; TEM: Typical Hospital, Rehabilitation Department, P.O Box ST 14, Southerton, Lobengula error of measurement; U: Under; VJ: Vertical jump test; W60: Wingate 60s cycle Road, Harare, Zimbabwe. 6Department of Physiotherapy, University of test; Yo-Yo IRT1: Yo-yo intermittent recovery test level 1; Yo-Yo IRT2: Yo-yo Witwatersrand, Faculty of Health Sciences, School of Therapeutic Sciences, 7 intermittent recovery test level 2 York Road, Parktown, Johannesburg, South Africa. 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