Comparing Changes in the Calf Muscle during Weight-bearing and Non-weight-bearing Stretching

Abstract

[Purpose] The aim of this study was to investigate and compare changes in muscle fascicle and tendon tissue behavior during stretching between a weight-bearing position and non-weight-bearing position. [Subjects] The study subjects were fifteen healthy individuals. [Method] Changes in the calf muscle after stretching in a weight-bearing and a non-weight-bearing position were compared using ultrasonography. Weight-bearing and non-weight-bearing stretching were performed for 30 seconds, and the medial gastrocnemius (MG) muscle fascicle length, pennation angle, and Achilles tendon length were measured before and after stretching. [Results] The post-stretching results in both positions showed increased fascicle length, decreased pennation angle, and increased Achilles tendon length compared with the pre-stretching results. Significant interactions were found between weight-bearing and stretching as evidenced by MG fascicle length and Achilles tendon length; specifically, the non-weight-bearing position increased the length more than the weight-bearing position. [Conclusion] This study revealed that while both weight-bearing and non-weight-bearing stretching were able to stretch the MG muscle and the Achilles tendon, non-weight-bearing stretching was more effective with regard to extending the MG muscle and Achilles tendon.