Hold-relax PNF is more effective than unilateral lumbar mobilization on increasing hamstring flexibility: A randomized clinical trial.

BACKGROUND: Although lumbar mobilization (LM) and proprioceptive neuromuscular facilitation (PNF) are used to increase flexibility in clinical practice, remains unclear which technic is the most effective. This study aims to verify and compare the immediate effect of unilateral LM and hold-relax PNF on hamstring flexibility. METHOD: A randomized, blinded, crossover trial carried out in university research laboratory. Thirty healthy young adults were randomly allocated to three groups, each group receive unilateral, central posterior-anterior LM grade III to the L4 joint, hold-relax PNF and control intervention in a different order with 48 h of washout period. Hamstring flexibility was measured using photogrammetry before and immediately after intervention through range of motion (ROM) change in the Straight Leg Raise Test. T-tests were used to compare ROM within groups, and ANOVA repeated measure followed by Bonferroni post-hoc tests was used for between groups comparison. RESULTS: Two participants were lost to follow-up, leaving 28 for analysis (21.6 ± 2.2 years-old). LM increased 4.5° (95% CI 2.3-6.5°, p = 0.001, d = 0.29) on the straight leg raise test and PNF increased 10.0° (95% CI 7.7-12.2°, p = 0.001, d = 0.7). No statistically significant increase was observed on the control group (p = 0.151, d = 0.08). Further, the technique used significantly influenced ROM (p = 0.001, η²p = 0.37). On the between group analysis, PNF was better than LM (p = 0.005) and control (p = 0.001), whereas LM was no better than the control for hamstring flexibility (p = 0.68). CONCLUSIONS: Although hold-relax PNF and unilateral LM techniques increased ROM, hold-relax PNF was more effective on increasing hamstring flexibility.