In vivo muscle architecture and size of the rectus femoris and vastus lateralis in children and adolescents with cerebral palsy


    Dr Noelle Moreau was a postdoctoral fellow in the Movement Science Program at Washington University in St Louis, MO, USA, when this study was conducted and was supported by a National Center for Medical Rehabilitation Research/National Institutes of Health grant (T32HD007434-16). This project was also supported by a clinical research grant from the Section on Pediatrics of the American Physical Therapy Association to Dr Moreau. The authors would like to thank Chris Stanley for assistance with data collection and processing, and Dr Janice Brunstrom and Jennifer Miros PT, for their support and assistance with recruitment. We would also like to thank GE Healthcare and Tania Gordley, Applications Specialist for GE Healthcare Ultrasound, for their support and technical assistance with this project.

Dr Noelle G Moreau at Medical University of South Carolina, Department of Health Professions, 151 B Rutledge Ave, MSC965, Charleston, SC 29425, USA. E-mail:


Aim  Our aim was to investigate muscle architecture and size of the rectus femoris (RF) and vastus lateralis (VL) in children and adolescents with cerebral palsy (CP) compared with age-matched typically developing participants.

Method  Muscle architecture and size were measured with ultrasound imaging in 18 participants with spastic CP (9 females, 9 males; age range 7.5–19y; mean age 12y [SD 3y 2mo]) within Gross Motor Function Classification System levels I (n=4), II (n=2), III (n=9), and IV (n=3) and 12 typically developing participants (10 females, 2 males; age range 7–20y; mean age 12y 4mo [SD 3y 11mo]). Exclusion criteria were orthopedic surgery or neurosurgery within 6 months before testing or botulinum toxin injections to the quadriceps within 3 months before testing.

Results  RF cross-sectional area was significantly lower (48%), RF and VL muscle thickness 30% lower, RF fascicle length 27% lower, and VL fascicle angle 3° less in participants with CP compared to the typically developing participants (p<0.05). Intraclass correlation coefficients were ≥0.93 (CP) and ≥ 0.88 (typical development), indicating excellent reliability.

Interpretation  These results provide the first evidence of altered muscle architecture and size of the RF and VL in CP, similar to patterns observed with disuse and aging. These alterations may play a significant role in the decreased capacity for force generation as well as decreased shortening velocity and range of motion over which the quadriceps can act.