The relationship between hamstring flexibility and vertical jump height

Abstract

Aim: This study investigated the relationship between hamstring flexibility (HF) and vertical jump height (VJH) or vertical jump power (VJP). A secondary aim was to analyse the same relationship following a four-week stretching programme. Results were also analysed in view of gender and sport. Method: 82 subjects including 46 males and 36 females participated in the study. Subjects included non-athletes, badminton players and athletes (athletics). Assessment of HF was performed using the sit-and-reach (SAR) test and the passive knee extension test (PKET). Assessment of VJH was performed using the countermovement jump-and-reach (CMJR) test and the squat jump-and-reach (SJR) test. VJP was estimated using peak power predictive equations. Null hypothesis: There is no significant relationship between HF and VJH. Alternative hypothesis: There is a significant relationship between HF and VJH. Results: Significant positive relationship was present between squat jump height (SJH) and SAR score (p = 0.026) when combining data derived from both sessions. A four-week programme of daily dynamic stretching followed by static stretching resulted in the relationship between SAR score and SJH to change from not statistically significant to significantly positive (p = 0.044) . Conclusion: The study suggests that in the population investigated, a statistically significant positive relationship between HF and VJH exists. The alternative hypothesis was accepted and the null hypothesis was rejected.