The acute effects of dynamic stretching on the neuromuscular system are independent of the velocity

This study examined the acute effects of dynamic stretching at different velocities on the neuromuscular system. Fourteen participants underwent four experimental sessions in random order: (1) control (lying at rest with the ankle in a neutral position); (2) slow velocity dynamic stretching (50 beats/min; SLOW_DS); (3) moderate velocity dynamic stretching (70 beats/min; MOD_DS); and (4) fast velocity dynamic stretching (90 beats/min; FAST_DS). The stretching protocols consisted of four sets of 10 repetitions and targeted the plantar flexor muscles of the right ankle. Assessments included corticospinal excitability (via motor-evoked potential-MEP/M_max), spinal reflex activity (via H-reflex-H_max/M_max), muscle contractile properties (peak twitch torque; PTT), maximal voluntary contraction (MVC), and maximal range of motion (ROM_max). Dynamic stretching did not affect MEP/M_max and MVC of the plantar flexor muscles (P > 0.05). All stretching protocols similarly reduced soleus H_max/M_max (P < 0.05), and increased PTT (P < 0.05). Additionally, all conditions, including control, similarly increase ROM_max (P < 0.05, and Cohen's d value of -0.39, -0.28, -0.38 and -0.29 for CON, SLOW_DS, MOD_DS and FAST_DS, respectively). Therefore, dynamic stretching reduces spinal reflex activity and enhances muscle contractile properties irrespective of movement velocity without impairing corticospinal excitability and MVC.