The effects of 12 weeks of static stretch training on the functional, mechanical, and architectural characteristics of the triceps surae muscle–tendon complex

Abstract Purpose We investigated the effects of 12 weeks passive static stretching training (PST) on force-generating capacity, stiffness, muscle architecture plantarflexor muscles. Methods Thirty healthy adults participated in study. Fifteen participants (STR, 6 women, 9 men) underwent 12-week muscles PST [(5 × 45 s-on/15 s-off) 2exercises] 5times/week (duration: 2250 s/week), while 15 (CTRL, served as control (no PST). Range motion (ROM), maximum resistive torque (PRT max ), triceps surae [fascicle length, fascicle angle, and thickness], stiffness [muscle–tendon complex (MTC) stiffness], plantarflexors maximun capacity variables (maximum voluntary contraction, activation, rate development, electromechanical delay) were calculated Pre, at 6th (Wk6), 12th week (Wk12) protocol both groups. Results Compared to STR ROM increased ( P < 0.05) Wk6 (8%) Wk12 (23%). PRT (30%, 0.05), MTC decreased (16%, 0.05). Muscle (11%) (16%). No changes found > Percentage correlated with percentage ρ = 0.62, 0.01) − 0.78, 0.001). In CTRL, no occurred any time point. Conclusion The expected long-term PST-induced associated modifications whole mechanical properties ankle joint, characteristics preserved. do not seem a sufficient stimulus induce architectural changes.