Uninvolved versus target muscle contraction during contract–relax proprioceptive neuromuscular facilitation stretching

Abstract

Objective The purpose of this study was to compare the acute effect of the contract–relax (CR) stretching technique on knee active range of motion (ROM) using target muscle contraction or an uninvolved muscle contraction. Design pre-test post-test control experimental design. Setting Clinical research laboratory. Participants Sixty healthy men were randomly assigned to one of three groups. Interventions The Contract–Relax group (CR) performed a traditional hamstring CR stretch, the Modified Contract–Relax group (MCR) performed hamstring CR stretching using contraction of an uninvolved muscle distant from the target muscle, and the Control group (CG) did not stretch. Main Outcome Measures Active knee extension test was performed before and after the stretching procedure. Results Two-way between-within analysis of variance (ANOVA) results showed a significant interaction between group and pre-test to post-test ( p < 0.001). Post-hoc examination of individual groups showed no significant change in ROM for the CG (0.8°, p = 0.084), and a significant moderate increase in ROM for both the CR (7.0°, p < 0.001) and MCR (7.0°, p < 0.001) groups. Conclusions ROM gain following a CR PNF procedure is the same whether the target stretching muscle is contracted, or an uninvolved muscle is contracted.