Effect of hamstring stretching on hamstring muscle performance.

The relationship between hamstring flexibility and hamstring muscle performance has not been reported. The purposes of this study were 1) to determine the most effective stretching method for increasing hamstring flexibility and 2) to determine the effects of increasing hamstring flexibility on isokinetic peak torque. Nineteen subjects participated in this study. A two-way analysis of variance was used to compare two stretching techniques: proprioceptive neuromuscular facilitation stretch and static stretch. A one-way repeated measures analysis of variance was used to compare hamstring isokinetic values pre- and poststretching. No significant increase occurred (p < .05) in hamstring flexibility even though increases occurred with each technique: static stretch (+21.3%) and proprioceptive neuromuscular facilitation (+25.7%). Significant increases occurred in peak torque eccentrically at 60 degrees/sec (p < .05, +8.5%) and 120 degrees/sec (p < .05, +13.5%) and concentrically at 120 degrees/sec (p < .05, +11.2%). No significant increase occurred at 60 degrees/sec (p > .05, +2.5%). We concluded that increasing hamstring flexibility was an effective method for increasing hamstring muscle performance at selective isokinetic conditions. Further study is needed to determine if increasing hamstring flexibility will increase performance in closed kinetic chain activities.