Purpose: Proprioceptive neuromuscular facilitation (PNF) stretching is considered a clinically effective way to enhance muscle properties; however, rare information exists about its effect on muscle flexibility and strength of the patients with stroke. To investigate the efficacy of PNF exercise on lower extremity muscle flexibility and strength after stroke. Methods: Twenty-four men with stroke were chosen for the current study and assigned to two groups, PNF (n=12, mean age=59.3) and control group (n=12, mean age=58.7). Both groups received conventional rehabilitation three times a week for two months, while the PNF group received an additional 20-minute contract-relax (CR) method of PNF exercises during each session. Gastrocnemius and hamstring flexibility have been measured pre- and post-intervention by wall lunge and active straight leg raising (aSLR) tests, respectively. Additionally, hamstring and quadriceps strength has been measured pre- and post-intervention by a hand-held dynamometer. A 2×2 mixed repeated measure analysis of variance (ANOVA) was utilized to analyze data. Results: Significant interaction of time x group was found for hamstring flexibility (F=33.24, P<0.01) and strength (F=23.86, P<0.01). Post hoc analysis indicated that aSLR (effect size=0.75) and hamstring strength (effect size=0.67) significantly increased in the PNF group. No significant interactions or main effects were observed for gastrocnemius flexibility and quadriceps strength. Conclusion: The results indicate that eight weeks of PNF stretching improves hamstring muscle flexibility and strength in patients with stroke. However, future studies have to confirm the prolonged effects of PNF exercise.
