The influence of foot position on lower leg muscle activity during a heel raise exercise measured with fine-wire and surface EMG.

OBJECTIVE

Exercises for lower leg muscles are important to improve function. To examine the influence of foot position on lower leg muscle activity during heel raises.

DESIGN

Cross-sectional laboratory study.

SETTING

Laboratory.

PARTICIPANTS

Fourteen healthy men participated in this study.

MAIN OUTCOME MEASURES

The muscle activity levels of the tibialis posterior (TP), peroneus longus (PL), flexor digitorum longus (FDL) and medial gastrocnemius (MG) were measured. The heel raises consisted of three foot positions: 1) neutral, 2) 30° abduction, and 3) 30° adduction. The EMG data for five repetitions of each foot position were normalized to maximum voluntary contraction. One-way repeated measure ANOVA was employed for statistical analysis.

RESULTS

The muscle activity level of TP, PL and FDL was significantly different between the three foot positions during the heel raises. TP and FDL showed the highest activity level in 30° foot adduction while PL demonstrated the highest activity level in 30° foot abduction.

CONCLUSIONS

Heel raises with 30° foot adduction and abduction positions can change lower leg muscle activity; These findings suggest that altering foot posture during the heel raise exercise may benefit patients with impaired TP, PL or FDL function.