The Effect of Different Distance Step Movements on Anticipatory Postural Adjustments Responses Under Predictable/ Unpredictable Conditions

Abstract

Purpose: The purpose of this study is to examine the effects of predictability of step distance and differences in step distance on Anticipatory Postural Adjustments (APA) responses in healthy young subjects.

Method: Twenty healthy young subjects performed step movements at three different distances according to their height in a condition in which the step distance was taught in advance and in a condition in which the step distance was presented immediately before the step. APA time, lower limb muscle activity time, and involvement of cortical activity by Electromyography (EMG) coherence analysis were calculated and compared for each condition.

Results: Significant differences in muscle activity time were observed for the tibialis anterior and soleus muscles on the step side according to predictability, and for the tibialis anterior and gastrocnemius lateralis muscle on the step side according to step distance, but no significant differences in APA time or coherence were observed.

Conclusion: The results suggest that the predictability of step distance and differences in step distance may have little effect on the APA response in healthy young subjects.