Cold Water Immersion Recovery after Simulated Collision Sport Exercise MONIQUE POINTON and ROB DUFFIELD School of Human Movement Studies, Charles Sturt University, Bathurst, New South Wales, AUSTRALIA ABSTRACT POINTON, M. and R. DUFFIELD. Cold Water Immersion Recovery after Simulated Collision Sport Exercise. Med. Sei. Sports Exerc. Vol. 44, No. 2, pp. 206-216, 2012. Purpose: This investigation examined the effects of cold water immersion (CWI) recovery after simulated collision sport exercise. Methods: Ten male rugby athletes performed three sessions consisting of a 2 x 30-min intermittent- sprint exercise (ISE) protocol with either tackling (T) or no tackling (CONT), followed by a 20-min CWI intervention (TCWI) or passive recovery (TPASS and CONT) in a randomized order. The ISE consisted of a 15-m sprint every minute separated by self-paced bouts of hard running, jogging, and walking for the remainder of the minute. Every sixth rotation, participants performed 5 x 10-m runs, receiving a shoulder-led tackle to the lower body on each effort. Sprint time and distance covered diuing ISE were recorded, with voluntary (maximal voluntary contraction; MVC) and evoked neuromuscular ñanction (voluntary activation; VA), electromyogram (root mean square (RMS)), ratings of perceived muscle soreness (MS), capillary and venous blood markers for metabolites and muscle damage, respectively measured before and after exercise, immediately after recovery, and 2 and 24 h after recovery. Results: Total distance covered during exercise was significantly greater in CONT (P = 0.01), without differences between TPASS and TCWI (P > 0.05). TCWI resulted in increased MVC, VA, and RMS immediately after recovery (P < 0.05). M-wave amplitude and peak twitch were significantly increased after recovery and 2 h after recovery, respectively, in TCWI {P < 0.05). Although TCWI had no effect on the elevation in blood markers for muscle damage {P > 0.05), lactate was significantly reduced after recovery compared with TPASS (P = 0.04). CWI also resulted in reduced MS 2 h after recovery compared with TPASS (P < 0.05). Conclusions: The introduction of body contact reduces exercise performance, whereas the use of CWI results in a faster recovery of MVC, VA, and RMS and improves muscle contractile properties and perceptions of soreness after collision-based exercise. Key Words: RUGBY, BODY CONTACT, PHYSIOLOGICAL LOAD, NEUROMUSCULAR, EXERCISE PERFORMANCE T eam sports are characterized by intermittent bouts of high-intensity activity, separated by short bouts of low-intensity activity (24). Further, many team sports such as rugby league, rugby union, Australian and American football, and soccer also involve regular collisions between opposing players throughout the course of training and/or match play. For example, participation in rugby league and rugby union requires players to be exposed to numerous (n = 2 0 ^ 0 ) direct physical collisions and tackles (7,17) throughout training and/or competition. The combative na- ture of such sports, cornbining intermittent high-intensity activity and repeated blunt force trauma, may result in micro- damage to skeletal muscle and postexercise muscle soreness (MS) (11,23). However, to date, few studies have attempted Address for correspondence: Monique Pointon, Ph.D., School of Human Movement Studies, Charles Sturt University, Panorama Avenue, Bathurst, New South Wales. Australia; E-mail: mpointonfaicsu.edu.au. Submitted for publication March 2011. Accepted for publication June 2011. 0195-9131/12/4402-0206/0 MEDICINE & SCIENCE IN SPORTS & EXERCISE® Copyright © 2012 by the American College of Sports Medicine DOI: 10.1249/MSS.0b013e31822b0977 to quantify the effect of body contact on ensuing exercise performance, and those that have report minimal effect of tackling because of insufficient tackling load (33). Regard- less, with many team sports training and competing over successive days, often with collision-based exercise, time available for physiological recovery can be limited (32). Because repeated collisions may result in potential residual MS and damage (25), such outcomes can adversely affect subsequent exercise performance (31). Accordingly, inter- ventions such as cold water immersion (CWI) that are aimed at improving postexercise recovery have become increas- ingly popular in many team sports. Although the body of literature on the effects of CWI recovery is growing, findings on potential benefits remain equivocal (20,32). In particular, and despite increased pop- ularity, there is a paucity of research examining the effect of CWI after high-intensity physical collision sport (4). To date, the study by Banfi et al. (4) is the only investigation to ex- amine the effects of CWI recovery after rugby (collision- based) exercise. Although no performance results were reported, CWI stabilized venous blood creatine kinase (CK) values, al- though CWI was combined with an initial active recovery. As such, the effect of CWI alone on performance and phys- iological recovery from rugby, or more specifically, collision- based exercise, remains unknown. Recently, Rowsell et al. 206