Loading...
Brief report : Passive mechanical properties of gastrocnemius in multiple sclerosis and ankle contracture
Hoang, Phu D. Psarakis, Michael Kwah, Li Khim Clarke, Jillian L. Gandevia, Simon C. Diong, Joanna
Hoang, Phu D.
Psarakis, Michael
Kwah, Li Khim
Clarke, Jillian L.
Gandevia, Simon C.
Diong, Joanna
Abstract
Background
Ankle contracture is common in people with multiple sclerosis (MS) but the mechanisms of contracture are not clear. This study aimed to identify the mechanisms of contracture in MS by comparing passive muscle length and stiffness at known tension, separated into contributions by muscle fascicles and tendons, between people with MS who had contracture and healthy people.
Methods
Passive length-tension curves of the gastrocnemius muscle-tendon unit were derived from passive ankle torque and angle using a published biomechanical method. Ultrasound images of medial gastrocnemius muscle fascicles were used to partition length-tension curves into fascicle and tendon components. Lengths and stiffness of the muscle-tendon unit, muscle fascicles and tendons were compared between groups with linear regression.
Findings
Data were obtained from 15 participants with MS who had contracture [age 53 (12) years, mean (SD)] and 25 healthy participants [48 (20) years]. Participants with MS had clinically significant ankle contracture, and had shorter fascicles at slack length (between-groups mean difference −0.8 cm, 95% CI −1.2 to −0.4 cm, p < 0.001) and at 100 N (−0.7 cm, 95% CI −1.3 to −0.1 cm, p = 0.02) compared to healthy participants. There were no differences between groups in all other outcomes.
Interpretation
Tension-referenced comparisons of passive muscle length and stiffness show that people with MS who had contracture had shorter fascicles at low and high tension compared to healthy people, but there were no changes to the muscle-tendon unit or tendon. Further studies are needed to identify the causes and mechanisms of contracture in neurological conditions.
Keywords
ankle, range of motion, muscle tendon unit, slack length, ultrasound, muscle fascicles, contracture
Date
2021
Type
Journal article
Journal
Clinical Biomechanics
Book
Volume
84
Issue
Page Range
1-5
Article Number
Article 105338
ACU Department
School of Allied Health
Faculty of Health Sciences
School of Behavioural and Health Sciences
Faculty of Health Sciences
School of Behavioural and Health Sciences
Collections
Relation URI
Source URL
Event URL
Open Access Status
License
All rights reserved
File Access
Controlled