The purpose of this study was to measure the change in hamstring muscle thickness between contracting and relaxing conditions following a
return to sports after a hamstring muscle strain and thereby evaluate muscle function. Six male track and field sprinters participated in this study.
All had experienced a prior hamstring strain injury that required a minimum of 2 weeks away from sport participation. Transverse plane scans
were performed at the following four points on the affected and unaffected sides under contracting and relaxing conditions: proximal biceps
femoris long head, proximal semitendinosus, middle biceps femoris long head, and middle semitendinosus. The results demonstrated an increase
in the thickness of the middle biceps femoris long head and middle semitendinosus regions on the unaffected side with contraction, whereas the
affected side did not show a significant increase. The proximal semitendinosus muscle thickness was increased with contraction on both the
unaffected and the affected sides. By contrast, the proximal biceps femoris muscle thickness did not show a significant increase on both sides.
The results of this study show that evaluation of muscle thickness during contraction may be useful for assessing the change in muscle function
after a hamstring muscle strain injury.
Copyright © 2015, Asia Pacific Knee, Arthroscopy and Sports Medicine Society. Published by Elsevier (Singapore) Pte Ltd. This is an open
access article under the CC BY-NC-ND license