Comparing the Effect of Exhaustive Fatigue Protocol on Ankle Muscle Co-contraction during Walking in Healthy and with a Pronated Foot People

Fatigue and deformities in the lower extremities such as the pronate foot can adversely affect the biomechanics of human movements and walking. Under fatigue conditions, the biomechanical differences of pronate and healthy feet are more easily identified. Therefore, the aim of this study was to investigate the effect of helpless fatigue protocol on all ankle muscle contractions in pronate and healthy individuals during walking.

Fourteen young men with pronate feet and 14 healthy men participated in this study. Electromyographic activity of selected muscles was recorded before and after the fatigue protocol. Data were analyzed using SPSS software and two-way analysis of variance with repeated measures.

The results showed that after fatigue, all general contractions in pronate and healthy foot groups decreased significantly during the heel contact phase (P=0.040). Also, the directional contraction in both groups increased significantly during the heel separation phase (P=0.022) and oscillation (P=0.039) in the pretest compared to the posttest. The other components did not show any significant differences.

The change in all the contractions of the muscles around the ankle joint indicates an increase in pressure on its internal structures. Abnormal anatomical changes in the feet of these people after fatigue may put them at risk for overload or injury. Therefore, it is suggested that in examining the effects of fatigue on gait mechanics and the incidence of gait injuries, attention should be paid to all muscle contractions in the joints.