Medial gastrocnemius muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic cerebral palsy

Barber, Lee, Barrett, Rod and Lichtwark, Glen (2012) Medial gastrocnemius muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic cerebral palsy. Journal of Biomechanics, 45 15: 2526-2530. doi:10.1016/j.jbiomech.2012.07.018


Author Barber, Lee
Barrett, Rod
Lichtwark, Glen
Title Medial gastrocnemius muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic cerebral palsy
Journal name Journal of Biomechanics   Check publisher's open access policy
ISSN 0021-9290
1873-2380
Publication date 2012-10-11
Sub-type Article (original research)
DOI 10.1016/j.jbiomech.2012.07.018
Volume 45
Issue 15
Start page 2526
End page 2530
Total pages 5
Place of publication Oxford United Kingdom
Publisher Pergamon
Collection year 2013
Language eng
Formatted abstract
Individuals with spastic cerebral palsy (CP) typically experience muscle weakness. The mechanisms responsible for muscle weakness in spastic CP are complex and may be influenced by the intrinsic mechanical properties of the muscle and tendon. The purpose of this study was to investigate the medial gastrocnemius (MG) muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic CP. Nine relatively high functioning young adults with spastic CP (GMFCS I, 17±2 years) and 10 typically developing individuals (18±2 years) participated in the study. Active MG torque-length and Achilles tendon properties were assessed under controlled conditions on a dynamometer. EMG was recorded from leg muscles and ultrasound was used to measure MG fascicle length and Achilles tendon length during maximal isometric contractions at five ankle angles throughout the available range of motion and during passive rotations imposed by the dynamometer. Compared to the typically developing group, the spastic CP group had 33% lower active ankle plantarflexion torque across the available range of ankle joint motion, partially explained by 37% smaller MG muscle and 4% greater antagonistic co-contraction. The Achilles tendon slack length was also 10% longer in the spastic CP group. This study confirms young adults with mild spastic CP have altered muscle-tendon mechanical properties. The adaptation of a longer Achilles tendon may facilitate a greater storage and recovery of elastic energy and partially compensate for decreased force and work production by the small muscles of the triceps surae during activities such as locomotion.
Keyword Contracture
Spasticity
Ultrasound
Physiological cross sectional area
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Human Movement and Nutrition Sciences Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 25 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 17 Oct 2012, 16:01:22 EST by Naomi Westwood on behalf of Paediatrics & Child Health - RBWH