Abstract
BACKGROUND: Hamstring flexibility is essential for preventing and treating musculoskeletal injuries, particularly low back pain. Self-myofascial release (SMR) of the plantar fascia, a technique involving a tennis ball, is often employed to enhance flexibility along the posterior "anatomy train." However, its specific effect on hamstring and lumbar spine flexibility remains uncertain. This study aimed to investigate and compare the effects of single-session and multiple-session SMR of the plantar fascia with those of traditional hamstring stretching on hamstring and lumbar spine flexibility. METHODS: A quasi-experimental study was conducted involving 24 participants, who were divided into three groups: Group A (single-session SMR), Group B (multiple-session SMR), and Group C (multiple-session hamstring stretching). Flexibility was assessed through the seated reach test (SRT) and active knee extension. RESULTS: The study population was predominantly female (58.33%), and no significant baseline differences were observed between the groups. Immediately after the intervention, all groups demonstrated slight improvements in flexibility, with Group B exhibiting the most significant gain (mean increase of 0.82 inches in the SRT). At the 6-day follow-up, Group B maintained the highest flexibility level (mean SRT of 13.05 inches). Groups B and C demonstrated significant long-term improvements in flexibility compared with baseline (Group B, p < 0.001; Group C, p = 0.01). CONCLUSION: Multiple-session SMR of the plantar fascia is an effective intervention for improving hamstring flexibility and range of motion of the lumbar spine. It can complement traditional stretching to enhance lower body flexibility and prevent injuries.