The Effect Of Cold-water Immersion On Joint Power During Drop-landings

Abstract

Exposure to cold environments results in pronounced alterations in many physiological systems. Military exercises, recreational situations, and popular winter sports could introduce large changes in tissue temperatures of the lower body. To date, the effect of cold exposure on joint mechanics during high impact activities (e.g. drop-landings) remains unknown. It is unclear whether cold exposure could reduce joints’ ability to absorb landing impact, which may increase risks of landing related injuries. PURPOSE: To determine the effect of cold-water immersion on lower-extremity joint power during drop-landings. METHODS: On four separate occasions, 11 female recreational athletes (22±2 yr, 65±7 kg, 1.67±0.06 m) performed drop-landings (single-leg and double-leg landings) from a 0.6-m height following 30-minute immersion in thermoneutral water (CON) (34 °C) to the hip-joint level and in cold-water (20 °C) to the ankle- (LOW), knee- (MED), and hip- (HIGH) joint levels. 3D motion capture was conducted. Lower-extremity joint power was calculated. One way repeated measures ANOVA was used to determine differences among the four conditions. RESULTS: No significant differences in peak power absorption among all testing conditions for either the single-leg landing (p>0.05) or double-leg landing (p>0.05). For single-leg landing, the mean±SD of the power absorption (W/kg) during water-immersions (CON, LOW, MED, and HIGH) were 22.1±3.4, 21.9±2.9, 22.0±3.1, 22.8±3.1, for the ankle, respectively, and 34.7±7.1, 34.4±6.3, 33.3±6.2, 34.4±7.5, for the knee, respectively, and 39.1±8.9, 39.9±11.3, 38.4±5.1, 39.5±8.3, for the hip, respectively. For double-leg landing, the power absorption during water-immersions (CON, LOW, MED, and HIGH) were 18.7±2.9, 19.2±2.8, 18.8±1.9, 18.6±2.8, for the ankle, respectively, and 32.6±6.0, 32.5±5.6, 31.5±4.0, 33.3±7.4, for the knee, respectively, and 33.3±14.1, 31.9±16.6, 29.9±12.8, 31.8±16.0, for the hip, respectively. CONCLUSION: For recreational athletes, drop-landing engages sub-maximal eccentric effort at leg’s muscle-tendon units to absorb impact. Although cold-water lowers tissue temperature, the ability of lower-extremity joints to absorb landing impact remains intact. Thus, the risk of landing related injuries may not be elevated due to cold exposure.