Effects of foot orthoses on walking and jump landing biomechanics of individuals with chronic ankle instability.

OBJECTIVES

To evaluate the kinematic, kinetic and electromyographic (EMG) immediate effects of foot orthoses (FOs) during walking, maximal single-leg side jump landing (SIDE) and unilateral drop landing on even (DROP), inclined and unstable (FOAM) surfaces in individuals with chronic ankle instability (CAI).

DESIGN

Cohort study.

SETTING

Biomechanics laboratory.

PARTICIPANTS

26 healthy individuals with CAI.

MAIN OUTCOME MEASURES

Ankle and knee angles/moments and lower-limb EMG of the gluteus medius, vastus medialis, vastus lateralis, biceps femoris, gastrocnemis medialis, gastrocnemius lateralis, peroneus longus and tibialis anterior muscles.

RESULTS

The main results are that with FOs, individuals with CAI exhibited decreased tibialis anterior muscle activity from 19 to 38% and 39-99% of the landing phase during the DROP task. They also exhibited increased biceps femoris muscle activity from 56 to 65% of the preactivation phase during walking. No significant ankle and knee joints angles and moments difference was observed when wearing FOs in any of the experimental tasks.

CONCLUSIONS

The results of this study suggest that the biomechanical effects of FOs are task-dependent and only affect EMG activity. They will help clinicians and researchers to better understand FOs' role in treatment and prevention of CAI.