The effect of different joint positions on the lengthened regions of the muscle during muscle stretching

Abstract

Purpose: We compared the degree of lengthening between the proximal and distal regions of the semitendinosus muscle during stretching with different joint positions. Subjects: Seven healthy men participated in the study. Methods: Each subject performed two stretching trials: 1) Straight leg raise (SLR) stretching, 2) Hip flexion and knee extension (HFKE stretching). Ultrasonography was used to assess the muscle architecture. Results: In the proximal region of the semitendinosus, the distance ratio between ischial tuberosity and tendinous intersection per muscle length of HFKE stretching was significantly larger than that of SLR stretching. In the distal region, the pennation angle of SLR stretching was significantly smaller than that of HFKE stretching, and the muscle thickness was not different between the two stretching conditions. Conclusion: These results indicate that the proximal region is lengthened more by HFKE stretching than by SLR stretching, and the distal region is lengthened more by SLR stretching than by HFKE stretching. This finding suggests that the lengthened regions can be changed by the position of the joints during stretching of bi-articular muscles.