足趾屈筋力と姿勢制御に対する冷水浸漬の影響

The great toe contributes to healthy gait and balance but may be impacted by exposure to cold. The purpose of this study was to examine the effects of 60 min of cold-water immersion on great toe flexor force and single-limb balance.

Forty-four healthy adults participated in one of two experiments. All participants placed one foot in water that was maintained at 10 °C and the other foot in water maintained at body temperature (37 °C) for 60 min. Both feet were submerged to a depth just above the malleolus. For the first experiment (n = 25), maximum voluntary great toe flexion force and control of submaximal force were measured while standing using a custom designed apparatus both before and immediately following immersion. For the second experiment (n = 19), postural sway was assessed before and after immersion while standing on an unstable surface with a single limb and eyes open.

Cold-water immersion resulted in a significant decrease in maximal flexor force of the great toe (332.6 ± 111.5 N vs. 235.1 ± 108.2 N, p < .001, Cohen's d = -0.89), but it did not impact the amount of error measured during control of submaximal flexor force (13.5 ± 4.4 N vs. 14.4 ± 5.6 N, p = .368). Further, exposure to cold resulted in significant increases to center of pressure rambling in the mediolateral direction (4.0 ± 0.9 mm vs. 4.8 ± 1.0 mm, p < .001, Cohen's d = 0.79) and trembling (3.2 ± 0.9 mm vs. 3.9 ± 1.4 mm, p = .002, Cohen's d = -0.63) and range of motion (49.6 ± 15.3 mm vs. 61.8 ± 21.9 mm, p = .007, Cohen's d = -0.62) in the anteroposterior direction.

Cold-water immersion can impact force at the great toe and may adversely affect balance.