Differences in gastrocnemius muscle architecture between the paretic and non-paretic legs in children with hemiplegic cerebral palsy

Background. The aim of this study was to investigate the architectural alterations of skeletal muscle following hemiplegic cerebral palsy. If associated with functional and clinical measures of disability, information on muscle architecture could then be used as an objective tool in the assessment of motor disability in these patients. Methods. Ultrasonography was used to assess in vivo the gastrocnemius muscle architecture in the paretic and non-paretic legs of eight children with cerebral palsy. Findings. Fascicle length and muscle thickness at the resting ankle position were reduced in the paretic compared to the non-paretic legs by up to 18% and 20%, respectively (P < 0.05), indicating a loss of both in-series and in-parallel sarcomeres in the affected muscles. However, pennation angle was similar (P > 0.05) in the two legs. Interpretation. The present results indicate that paresis in hemiplegic cerebral palsy may affect the geometry of skeletal muscle. Further studies are required to examine the relation between muscle architecture, severity of motor disability, and treatment. (c) 2007 Elsevier Ltd. All rights reserved.