Effects of warm-up and stretching on ankle joint flexibility in individuals with and without hamstring tightness

Introduction Many individuals, not just professional athletes, who require high lower-extremity flexibility perform pre-exercise stretching. Although a significant number of these individuals may not experience lower-extremity muscle tightness, most related studies to date have focused on individuals with muscle tightness. This study aimed to investigate the acute effect of warm-up and stretching on lower-extremity flexibility, including the ankle joint, in individuals with hamstring tightness (HT group) versus those without hamstring tightness (NoHT group). Methods Lower-extremity flexibility was measured before warm-up, after warm-up, after stretching, 1 min after stretching, and 2 min after stretching. Range of motion was measured using an active straight leg raise (ASLR), active knee extension (AKE), and active dorsiflexion (ADF). Results The warm-up did not significantly increase AKE in the HT group; however, a marginal increase in AKE was noted in the NoHT group. Stretching significantly increased AKE and ASLR in the HT group and AKE, ASLR, and ADF in the NoHT group. The increase in AKE after stretching was maintained for up to 1 min in the HT group and 2 min in the NoHT group. Conclusions A warm-up effect was observed only in the NoHT group. While the stretching effects were significant in both groups, they lasted longer in the NoHT group. Unlike AKE and ASLR, ADF was not significantly influenced by hamstring tightness at baseline. In conclusion, contrary to expectations, the acute effect of stretching on lower-extremity flexibility was less in individuals with versus without hamstring tightness.