Effect of different stretch amplitudes of dynamic stretching on joint range of motion

Abstract

This study examined the effects of different dynamic stretching (DS) amplitudes on joint range of motion (ROM), passive torque (PT), and subjective fatigue. Twelve healthy subjects (age [mean ± SD] = 19.3 ± 1.0 years) underwent three experimental trials: DS at maximal active ankle plantarflexion-dorsiflexion ROM (DS100), DS at 80% maximal active ROM (DS80), or control. Ankle angle and PT were measured before and after DS with the ankle passively dorsiflexed at 1º/s to its maximal ROM. DS consisted of four sets of 30 s of ankle plantarflexion-dorsiflexion at 100 beats/min while standing. Subjective fatigue during DS was measured using the visual-analogue scale. Maximal ankle dorsiflexion angle was significantly increased after DS100 (20.6 ± 3.5º to 23.8 ± 3.8º, P < 0.05); no changes were seen after DS80/control. Subjective fatigue was significantly greater at two (2.6 ± 0.7 mm vs 1.2 ± 0.3 mm), three (3.7 ± 0.9 mm vs 1.3 ± 0.3 mm), and four (5.2 ± 0.9 mm vs 1.6 ± 0.3 mm) sets of DS100 than with DS80 (P < 0.05). PT at maximal dorsiflexion increased from before to after stretching (DS100: 26.3 ± 3.2 Nm to 30.4 ± 3.4 Nm, DS80: 28.8 ± 3.0 Nm to 31.0 ± 3.3 Nm, Control: 26.6 ± 2.8 Nm to 29.1 ± 3.5 Nm, P < 0.05), although there were no significant differences among trials. These results indicated that greater active ROM during DS is important for increasing joint ROM, although DS with greater active ROM induces greater subjective fatigue.