Acute effects of static passive vs contract- relax short-duration stretching on isometric and isokinetic performance in knee muscles: A single-group, pilot study
Affiliations: [a] Faculty of Sport, Pablo de Olavide University, Seville, Spain | [b] APERE EA-3300 Laboratory Sciences and STAPS, Jules Verne University of Picardie, Amiens, France
Correspondence:
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Corresponding author: Juan Antonio León-Prados, Faculty of Sport, Pablo de Olavide University, Ctra. de Utrera km 1. 41013, Seville, Spain. Tel.: +34 606701338; E-mail: [email protected].
Abstract: BACKGROUND: Research suggests that the effect of short bouts of stretching on muscle strength and ROM gains depends on the total stretching volume. OBJECTIVE: We assessed the effects of short bouts of static passive (SSS) and contract-relax (SCR) stretching on range of motion (ROM) and muscular strength. METHODS: Twenty volunteers performed two stretch protocols in a randomized order on two separate days, using the SSS and SCR techniques. Maximal ROM was tested prior to (pre-S), immediately after (post-I) and 10 minutes after (post-10) the stretch protocol. Maximal isometric voluntary contraction (MVC), isokinetic concentric peak moment (F-PM) and angle of peak moment (F-PMa) in the knee flexors, and concentric flexion/extension PM ratio (F/E) were measured and evaluated before (pre) and after (post) the stretch protocol. RESULTS: Both stretching techniques showed significant time-effects (pre vs post-I and post-10) but no interaction effects (time × techniques). There were small but significant effects between intervention-paired comparisons for F-PM, F-PMa and F/E ratios after SSS, and for F-MVC and F-PMa measures after SCR stretch techniques. CONCLUSIONS: Short-stretch techniques have trivial and small effects on loss of strength, increase the ROM for at least 10 min and slightly decrease the concentric F/E ratio. Using SSS could create some risk of hamstring injuries.
