Effects of Dynamic Stretching Velocity on Joint Range of Motion, Muscle Strength, and Subjective Fatigue.

Mizuno, T. Effects of dynamic stretching velocity on joint range of motion, muscle strength, and subjective fatigue. J Strength Cond Res 36(9): 2440-2447, 2022-The purpose of this study was to determine the effects of 2 different dynamic stretching (DS) velocities on joint range of motion (ROM), isometric muscle strength, and subjective fatigue during DS. Fifteen healthy male subjects performed DS at 2 different velocities: maximal active ankle plantar flexion-dorsiflexion velocity (DS100) and 50% of maximal velocity (DS50). A passive dorsiflexion test and isometric maximal voluntary contractions (MVCs) of the ankle plantar flexors and dorsiflexors were performed before and after DS. During the passive dorsiflexion test, ankle ROM and passive torque were measured when the ankle was passively dorsiflexed at 1°·s -1 to its maximal ROM. The DS consisted of 4 sets of 10 ankle plantar flexions/dorsiflexions. For DS100, subjects flexed and extended their ankle as quickly as possible, whereas for DS50 the rhythm of the DS was controlled by a metronome. Subjective fatigue during DS was assessed using a visual analog scale. Maximal ankle ROM and passive torque at the maximal dorsiflexion angle were significantly increased after both DS100 and DS50 ( p < 0.05), although there was no significant difference between these trials. The passive torque at submaximal angles and the isometric MVC of the ankle plantar flexors and dorsiflexors were not changed in either condition. However, there was a greater difference in subjective fatigue from prestretching to after 4 sets after DS100 than DS50 ( p < 0.05). These results indicate that DS velocity did not influence subsequent joint flexibility. However, DS of moderate speed is recommended because faster DS seems to be associated with greater fatigue.