Related Experiment Video
Updated: Jul 17, 2026
Evaluating Postural Control and Lower-extremity Muscle Activation in Individuals with Chronic Ankle Instability
Published on: September 18, 2020
The ability of the Biodex Stability System to distinguish level of function in subjects with a second-degree ankle
Marc Perron1, Luc J Hébert, Bradford J McFadyen
1Physiotherapy Clinic, Valcartier Garrison, 5th Field Ambulance, Canadian Forces Health Services and Rehabilitation Department, Faculty of Medicine, Laval University, Quebec City, Canada. Perron.mm@forces.gc.ca
Objective:
To assess the capacity of the Biodex Stability System using a one-leg stance protocol to differentiate between injured and non-injured limbs and between level of disabilities.
Design:
Cross-sectional study.
Setting:
Military and civilian clinic.
Subjects:
Thirty-four individuals with a second-degree lateral ankle sprain and 36 healthy subjects.
Methods And Measures:
Subjects were tested on the Stability System 30 days after injury using a one-leg stance protocol in the dynamic limit-of-stability mode. All subjects also filled out a disability questionnaire (Lower Extremity Functional Scale). The groups were compared based on the overall dynamic limit-of-stability score and its relationship with the score on the disability questionnaire was also examined.
Results:
The overall dynamic limit-of-stability scores (subjects with a lateral ankle sprain: 13.0% (5.5)-26.0% (9.2); healthy subjects: 16.9% (7.9)-27.9% (9.6)) clustered in the lower end of the theoretical range of 0-100%. Statistically significant differences in the overall dynamic limit-of-stability scores were found between the injured and non-injured limbs but group differences were small and clinically not relevant. No significant relationships were found between the overall dynamic limit-of-stability scores and the Lower Extremity Functional Scale scores (58.2 (11.8)) of the subjects with a lateral ankle sprain.
Conclusions:
The one-leg stance protocol carried out in the dynamic limit-of-stability mode is very challenging and offers a very limited capacity to differentiate between injured and non-injured limbs. The main outcome of the Stability System does not appear to be a good indicator of the functional capacity of people with a lateral ankle sprain.
