Short-Term Effects of Active Posterior Chain Stretching With and Without Plantar Fascia Mobilization on Hamstring Flexibility and Movement Kinematics in Individuals With Hamstring Tightness

Background: The plantar fascia is anatomically connected to the posterior chain through the superficial back line and may influence hamstring flexibility and body segment movement. However, evidence regarding the combined effects of plantar fascia mobilization (PFM) and posterior chain stretching across consecutive intervention sessions remains limited. Objectives: To compare the effects of active posterior chain stretching (APCS) alone and APCS combined with PFM (APCS+PFM) on hamstring flexibility, body segment kinematics, and sit and reach performance in individuals with hamstring tightness. Methods: Eighteen female university students with hamstring tightness were randomly allocated to the APCS or APCS+PFM group. Popliteal angle, body segment angular excursions, and sit and reach score excursion were assessed at baseline (T0), immediately post-intervention (T1), and after three consecutive days (T2). Data were analyzed using a 2 × 3 (group × time) mixed-design repeated-measures ANOVA. Results: A significant group × time interaction was observed for popliteal angle (p = 0.046; Effect size = 0.122), with greater improvement in the APCS+PFM group. Significant main effects of time were found for pelvic and hip angular excursions and sit and reach score excursion (p < 0.05), with post hoc analysis indicating progressive improvements over time. Conclusion: APCS+PFM produced greater short-term improvements in hamstring flexibility than APCS alone. Both interventions also improved pelvic and hip kinematics and sit and reach performance over time. These findings provide preliminary evidence supporting PFM as an adjunct to enhance the effectiveness of posterior chain stretching in female university students with hamstring tightness.