Athletes

Yang Zhu et al. (2026) · PeerJ

This systematic review and meta-analysis pooled 22 randomized controlled trials with 375 mostly male participants to ask when, if at all, a single cold-water immersion (CWI) after exercise helps muscles recover. CWI means immersing the body, from navel depth up to the neck, in water of roughly 5 to 20 degrees C for about 6 to 20 minutes. Exercise-induced muscle damage (EIMD) is the loss of force, soreness and raised creatine kinase (CK, a blood marker leaking from stressed muscle cells) that follows hard or unaccustomed exercise, often with delayed onset muscle soreness (DOMS). Earlier reviews mixed time points, so this one separated results at 0, 24, 48 and 72 hours. The included trials enrolled healthy non-athletes and athletes aged about 16 to 49, who exercised with intervals, simulated matches, distance running or heavy eccentric lifting. After exercise, one group sat in cold water and the comparison group rested seated for a similar time. Researchers measured maximal voluntary isometric contraction (MVIC, the hardest possible static muscle squeeze), countermovement jump (CMJ, jump height as a gauge of explosive power), CK, and soreness on a visual analog scale (VAS, a line marked from no pain to worst pain). Maximal strength was unchanged by CWI (g = 0.08, 95% CI -0.11 to 0.26, p = 0.42; a negligible effect) at every time point. Jump performance was worse immediately afterward (g = -0.68, p = 0.01; a medium-sized drop) and showed no difference by 24 to 48 hours (g = 0.38 at 24 h, p = 0.06; g = 0.06 at 48 h, p = 0.68). CK looked lower after CWI (g = -0.43, p < 0.001; a small effect), but the result shrank to non-significance after correcting for likely missing small studies (g = -0.16, 95% CI -0.44 to 0.12; the original benefit was probably overestimated). Soreness was lower (g = -0.58, p = 0.006; a medium effect), though the trials disagreed widely (I² = 87%) and the certainty of evidence was rated very low. The evidence has clear limits: 362 of 375 participants were male, participants could not be blinded to cold water, several trials were tiny, and only one immersion with follow-up of 72 hours or less was studied. The authors suggest the soreness effect is the most plausible benefit and the temporary jump decrement is the main drawback. Repeated use during training and its effect on muscle adaptation were not examined, and they call for larger trials that include women and standardize temperature and duration.