Time-based effects of different duration stretching on calf muscle strength

BACKGROUND: There are conflicting reports on the acute effects of stretching on muscle strength. Some studies report reduction in muscle strength however others report no change following stretching. OBJECTIVE: To assess the acute effects of static stretching (SS) of different durations on the isometric maximum voluntary contraction force (MVCF) of the calf muscle. METHODS: Pretest-posttest experimental design was used. Ten male participants (mean age 25.4 ± 2.11 years) participated in three experimental trials: SS for 2-minutes (SS2), 4-minutes (SS4), and 8-minutes (SS8). MVCF was measured before, immediately after, at 10- and 20-minutes post-stretch intervals. Each SS trial involved varied repetitions of 30-seconds stretches and 20-seconds relaxation periods. The isometric maximum voluntary contraction force (MVCF) was the outcome measure. RESULTS: SS2, SS4, and SS8 did not change the MVCF at 0-, 10- and 20-minutes post stretching intervals (p> 0.05). CONCLUSIONS: 2-, 4-, and 8-minutes intermittent SS did not change the isometric muscle strength in the Calf muscle up to 20 minutes after stretching and thus can safely be performed before those sporting events that require significant muscle strength.