The purpose of this study was to compare the immediate effects of a hold-relax proprioceptive neuromuscular facilitation stretching (HR-PNF) versus static stretch (SS) on hamstring flexibility in healthy, asymptomatic subjects. Thirty subjects (13 female; mean age 25.7 ± 3.0, range 22–37) without excessive hamstring muscle flexibility were randomly assigned to one of two stretch groups: HR-PNF or SS. The left leg was treated as a control and did not receive any intervention. The right leg was measured for ROM pre- and post-stretch interventions, with subjects receiving randomly assigned interventions one week apart. Data were analyzed with a 3 (intervention: HR-PNF, SS, control) × 2 (time: pre and post) factorial ANOVA with repeated measures and appropriate post-hoc analyses. A significant interaction was observed between intervention and time for hamstring extensibility, F(2,58) = 25.229, p < .0005. Main effect of intervention for the tested leg was not significant, p = .782 indicating that there was no difference between the two stretch conditions. However, main effect for time was significant (p < .0005), suggesting that hamstring extensibility (for both stretching conditions) after intervention was greater than before.
No significant differences were found when comparing the effectiveness of HR-PNF and SS techniques. Both stretching methods resulted in significant immediate increases in hamstring length.
Emilio J. Puentedura, Peter A. Huijbregts, Shelley Celeste, Dale Edwards, Alastair In, Merrill R. Landers and Cesar Fernandez-de-las-Penas. Physical Therapy in Sport, In Press, Corrected Proof, Available online 15 April 2011,