Background: Although it has been reported that both self-myofascial release (SMR) with foam rolling (FR) and active static hamstring stretching (e.g., jackknife stretching) are effective in improving hamstring flexibility, no study has compared the effects of these exercises.
Objectives: To compare the effects of SMR with FR and jack-knife stretching on hamstring flexibility.
Design: A Randomized controlled trial.
Methods: Subjects with hamstring tightness were divided into the SMR with the FR group (n=12) and the jack-knife stretching group (n=12). Subjects groups performed SMR with FR or jack-knife stretching according to group assignment. To identify changes in hamstring flexibility, the finger-to-floor distance (FFD) test, active knee extension (AKE) test, and passive straight leg raising (PSLR) test were performed at pre- and post-exercise.
Results: Significant increases occurred in knee extension angle during the AKE test and hip flexion angle during the PSLR test after exercise in both groups (P<.001). Additionally, FFD and anterior pelvic tilt during the FFD test significantly increased (P<.001); however, we observed no significant interaction and main effects for the groups (P>.05).
Conclusion: Both SMR with FR and jack-knife stretching are effective in improving hamstring flexibility in subjects with hamstring tightness.

INTRODUCTION
SUBJECTS AND METHODS
    Subjects
    Experimental Procedures
    FFD test
    Knee and Hip ROM
    SMR with FR
    Jack-Knife Stretching
    Data and Statistical Analysis
RESULTS
DISCUSSION
CONCLUSION
REFERENCES

• Minhyeok Kang(Department of Physical Therapy, College of Health Sciences, Catholic University of Pusan) Correspondence