Vaile, J.M., N.D. Gill, and A.J. Blazevich. The effect of contrast water therapy on symptoms of delayed onset muscle soreness. J. Strength Cond. Res. 21 (2): 697-702. 2007.-This study examined the effect of contrast water therapy (CWT) on the physiological and functional symptoms of delayed onset muscle soreness (DOMS) following DOMS-inducing leg press exercise. Thirteen recreational athletes performed 2 experimental trials separated by 6 weeks in a randomized crossover design. On each occasion, subjects performed a DOMS-inducing leg press protocol consisting of 5 ϫ 10 eccentric contractions (180 seconds recovery between sets) at 140% of 1 repetition maximum (1RM). This was followed by a 15-minute recovery period incorporating either CWT or no intervention, passive recovery (PAS). Creatine kinase concentration (CK), perceived pain, thigh volume, isometric squat strength, and weighted jump squat performance were measured prior to the eccentric exercise, immediately post recovery, and 24, 48, and 72 hours post recovery. Isometric force production was not reduced below baseline measures throughout the 72-hour data collection period following CWT (ഠ4-10%). However, following PAS, isometric force production (mean Ϯ SD) was 14.8 Ϯ 11.4% below baseline immediately post recovery (p Ͻ 0.05), 20.8 Ϯ 15.6% 24 hours post recovery (p Ͻ 0.05), and 22.5 Ϯ 12.3% 48 hours post recovery (p Ͻ 0.05). Peak power produced during the jump squat was significantly reduced (p Ͻ 0.05) following both PAS (20.9 Ϯ 13.4%) and CWT (12.8 Ϯ 8.0%), with the mean reduction in power for PAS being marginally (not significantly) greater than for CWT (effect size ϭ 0.76). Thigh volume measured immediately following CWT was significantly less than PAS. No significant differences in the changes in CK were found; in addition, there were no significant (p Ͼ 0.01) differences in perceived pain between treatments. Contrast water therapy was associated with a smaller reduction, and faster restoration, of strength and power measured by isometric force and jump squat production following DOMS-inducing leg press exercise when compared to PAS. Therefore, CWT seems to be effective in reducing and improving the recovery of functional deficiencies that result from DOMS, as opposed to passive recovery.