Abstract
The purpose of this study was to clarify the effect of bathing duration in the artificial carbon dioxide-rich water on the maximal dorsiflexion angle of the ankle joint. Eight healthy young male subjects participated in this study. The passive torque and ankle joint angle were measured during the passive-dorsiflexion test, in which the ankle was passively dorsiflexed at a speed of 1 deg/s to the maximal dorsiflexion angle. After the passive-dorsiflexion test, subjects were performed the artificial carbon dioxide-rich water-bathing or the fresh water-bathing for 5, 10 and 20 min in different days. Thereafter, subjects were performed the passive-dorsiflexion test, again. As a result, maximal dorsiflexion angle of the ankle joint was significantly increased after bathing both the artificial carbon dioxide-rich water and the fresh water for 10 min (P < 0.05), and passive torque at the maximal dorsiflexion angle of the ankle joint were significantly increased after bathing both the artificial carbon dioxide-rich water and the fresh water (P < 0.05). The cutaneous blood flow was significantly increased after the artificial carbon dioxide-rich water-bathing trials (P < 0.05), but no significant change was identified after the fresh water-bathing. These results clarified both the artificial carbon dioxide-rich water-bathing and the fresh water-bathing in fixed position for 10 min at neutral temperature increased maximal dorsiflexion angle of the ankle joint.
