Ultrastructural revelation of the nature of pennation in the abdominal muscles of children with spastic type cerebral palsy (stcp): Implications for force generation

Abstract

Purpose: To investigate whether the pennation angle (PA) in the abdominal muscles of individuals with spastic type cerebral palsy (STCP) has undergone any change when compared with those of typically developing (TD) individuals. To determine whether PA of abdominal muscles in individuals with STCP impacts differently on the force generating capacity, from those of TD peers. Materials & methods: Ultrasound images of the four abdominal muscles namely; rectus abdominis (RA), internal oblique (IO), external oblique (EO) and transversus abdominis (TrA), were obtained during the resting and active stages. ImageJ software package (version 2012) was used to measure the PA of the sonographic images. Sixty-three individuals with STCP and eighty-two typically developing (TD) individuals took part in the study. The participants were between the ages of 7 and 16 years. Results: The PA for three out of the four abdominal muscles was less than 3∘ while the RA muscle in both groups showed a pennation angle of zero degrees during the resting and active stages. Conclusion: Excluding the rectus abdominis muscle, PA appeared to be altered in individuals with STCP when compared to their TD counterparts. The characterization of PA in abdominal muscles in both groups is, however, unclear. The PA as a muscle parameter may not be an important variable for differentiating the force generating capacity between individuals with STCP and their TD peers. Further investigation is required on MAP and the overall implication of each component on abdominal muscle function, especially in the maintenance of balance and posture.