Affiliations: Department of Mechanical Engineering, Stanford
University, Stanford, CA, USA | Functional & Applied Biomechanics Section, NIH
Clinical Center, Bethesda, MD, USA | Department of Pediatrics, University of Gothenburg,
Gothenburg, Sweden | Department of Physiotherapy, Stellenbosch University,
Tygerberg, South Africa | Department of Bioengineering, Stanford University,
Stanford, CA, USA
Note: [] Corresponding author: Scott Delp, Clark Center, Room S-321, 318
Campus Drive, Stanford, CA 94305, USA. Tel.: +1 650 723 1230; Fax: +1 650 723
8544; E-mail: delp@stanford.edu
Abstract: Muscle weakness may contribute to crouch gait in individuals with
cerebral palsy, and some individuals participate in strength training programs
to improve crouch gait. Unfortunately, improvements in muscle strength and gait
are inconsistent after completing strength training programs. The purpose of
this study was to examine changes in knee extensor strength and knee extension
angle during walking after strength training in individuals with cerebral palsy
who walk in crouch gait and to determine subject characteristics associated
with these changes. A literature review was performed of studies published
since January 2000 that included strength training, three-dimensional motion
analysis, and knee extensor strength measurements for individuals with cerebral
palsy. Three studies met these criteria and individual subject data was
obtained from the authors for thirty crouch gait subjects. Univariate
regression analyses were performed to determine which of ten physical
examination and motor performance variables were associated with changes in
strength and knee extension during gait. Change in knee extensor strength
ranged from a 25% decrease to a 215% increase, and change in minimum knee
flexion angle during gait ranged from an improvement of
9° more knee extension to
15° more knee flexion. Individuals without hamstring
spasticity had greater improvement in knee extension after strength training.
Hamstring spasticity was associated with an undesired increase in knee flexion
during walking. Subject-specific factors such as hamstring spasticity may be
useful for predicting which subjects will benefit from strength training to
improve crouch gait.
