The effects of ankle compliance and flexibility on ankle sprains.

PURPOSE: The goal of this study was to examine the influence of changes in subtalar joint flexibility and compliance on ankle sprain occurrence.

METHODS

Muscle model driven simulations of 10 subjects performing the landing phase of a side-shuffle movement were performed. The passive flexibility or compliance of the subtalar joint was varied, and each subject-specific simulation was exposed to a set of perturbed floor conditions.

RESULTS

Increases in flexibility and compliance both led to an increase in the occurrence of excessive supination, while changes in flexibility had a greater influence. Changes in flexibility or compliance caused only small changes in the occurrence of excessive supination torques.

CONCLUSION

These results suggest that increased mechanical laxity does not directly cause an increase in sprain occurrence during side-shuffle movements.