Cold water immersion (CWI) is a widely used recovery therapy. It is purported to reduce signs and symptoms of muscle soreness and increase a sense of wellbeing, partly by acutely reducing or delaying the inflammatory response. However, inflammation is an important component of muscle regeneration and adaptation following muscle injury. Therefore, by reducing inflammation in skeletal muscle, regular CWI may inhibit adaptation to training.
PURPOSE: To investigate the effects of regular CWI on strength and muscle hypertrophy following long-term resistance training.
METHODS: Young men experienced in resistance training were matched for body mass, strength and muscle mass, and divided into two groups. Both groups performed progressive high-intensity resistance training twice a week for 12 weeks. Immediately after each training session, one group (CWI; n=11) immersed their lower body in 10C water for 10 min, whereas the other group (ACT; n=10) cycled at a low-intensity for 10 min. Training adaptation was assessed by measuring changes in maximal isometric torque and rate of force development (RFD), isokinetic dynamic strength, leg press and knee extension strength, thigh and gluteal muscle mass (by dual energy X-ray absorptiometry).
RESULTS: Following training, there were significant (p<0.05) increases in the following variables within the CWI and ACT groups, respectively: leg press strength (43% vs 65%; ES 3.1 vs 4.9), knee extension strength (20 vs 39%; ES 1.7 vs 4), maximum isometric torque (10% vs 25%; ES 0.7 vs 1.5), RFD impulse (18% vs 32%; ES 0.7 vs 1.7), isokinetic (6% vs 18%; ES 0.4 vs 1.4) and lean muscle mass (4.1% vs 8.5%; ES 0.4 vs 1.6). Training-induced changes in isometric torque (p=0.042) and isokinetic torque (p=0.044), RFD (p=0.024) and knee extension strength (p=0.022) were significantly smaller in the CWI group. Changes in leg press strength (p=0.1) and lean muscle mass (p=0.3) were not significantly different between the groups.
CONCLUSION: Regular cold water immersion attenuated improvements in strength and lean muscle mass following progressive high-intensity resistance training. Athletes should therefore reconsider whether to use cold water immersion as a strategy to recover from exercise.
Supported by an ACSM Foundation Research Grant from the American College of Sports Medicine Foundation.