Effectiveness of Vibration Foam Roller Stretching and Ballistic Stretching on Hamstring Flexibility among Amateur Male Athletes – A Randomized Control Trial
Bhuvaneshwar Siva, K Kotteeswaran, Jeevarathinam Thirumalai, Kiran Gajendran · Journal of Health Science and Medical Research · 2026
Objective: The primary
objective of this study was to compare the effectiveness of vibration foam-roller stretching and ballistic stretching in improving hamstring flexibility, assessed using the active knee extension test and the sit-and-reach test.Material and
Methods: A total of 80 participants (aged 18 to 25 years) were randomly allocated into two equal groups using a concealed envelope
Method: . Sealed, opaque envelopes containing group assignments (Group A: vibration foam roller stretching; Group B: ballistic stretching) were prepared by an independent researcher not involved in recruitment or assessment. After baseline evaluation, participants were assigned sequentially by opening the next envelope, ensuring allocation concealment. Group A (n=40) received vibration foam roller stretching, and Group B (n=40) received ballistic stretching to improve hamstring flexibility. Both groups completed three training sessions per week over four weeks. The primary outcome was hamstring flexibility, measured using the active knee extension (AKE) test in degrees (°). The secondary outcome was the sit-and-reach test (SRT) in centimeters (cm). Assessments were conducted at baseline and immediately post-intervention to evaluate within- and between-group differences.
Results: The ballistic stretching group showed significantly greater post-intervention improvements across all outcome measures. In the AKE test, right-side mean±S.D. values were 149°±12.27 versus 129.8°±1.03, and left-side values were 149.5°±12.21 versus 130.2°±0.74, both showing enhanced outcomes in the ballistic group (p-value<0.001). Similarly, in the SRT, the ballistic group achieved a mean±S.D. of 28.9±1.39 cm compared to 21.2±1.73 cm in the vibration foam roller group (p-value<0.001).
Conclusion: Ballistic stretching was more effective than vibration foam roller stretching in improving hamstring flexibility among amateur male athletes. Clinically, these
Findings: suggest that ballistic stretching can be safely integrated into physiotherapy and sports training programs to prevent hamstring tightness and reduce the risk of flexibility-related injuries.