Acute effect of stretching prior to resistance training on morphological, functional and activation indicators of skeletal muscle in young men

Abstract

Purpose The study aimed to evaluate the acute efect of stretching prior to a resistance training (RT) session on morphological, functional, and activation indicators of skeletal muscle. Methods 10 men (19.80±1.48 years), were allocated to two experimental conditions: RT protocol (PRT), who performed 4 sets of 6–12 repetitions of the knee extension exercise, at 70% of the maximum dynamic strength; and stretching+RT protocol (PSRT), which performed 3 series of passive stretching for 30 s, for femoral quadriceps muscles (knee fexion), followed by the same protocol performed on the PRT. Perimeter and skinfold of the thigh, maximum isometric force, 1RM and muscle power at 40%, 60%, and 80% of 1RM and electromyography signal of rectus femoris, vastus lateralis, and vastus medialis were evaluated. Results No diferences were found for the baseline values of any variable in the two experimental conditions (p >0.05). There were no signifcant diferences between the two experimental conditions for anthropometric variables (p>0.05), for the diferent manifestations of strength evaluated (p>0.05) and for the muscle activation of the diferent muscles evaluated (p>0.05). Conclusion Stretching prior to RT does not decrease strength, does not alter muscle activation, volume and internal training load, when compared to the same protocol, without performing previous stretching.