|dc.description.abstract||Athletes are exposed to training stimuli that lead to temporary states of impaired performance (i.e. fatigue). Adaptation from training will occur in response to the balance between the training load and recovery. Frequently, athletes are exposed to high density training phases, leaving only limited timeframes for recovery between training sessions and/or competition. Therefore, in order to enhance recovery, different modalities are commonly implemented. Given its efficacy in the research literature, cold modalities, in particular cold-water immersion (CWI), is a frequently employed and studied recovery modality. While the effects of CWI on enhancing recovery in the acute timeframe are widely investigated, recent research has demonstrated that chronic exposure to CWI may decrease anabolic pathway signaling, therefore reducing muscle growth adaptations. However, there is currently a lack of well-designed studies on chronic use of CWI in athletic populations exposed to high training loads and frequencies.
The purpose of this series of studies was to compare the acute and chronic effects of CWI in well-trained and elite team sport athletes. This thesis comprises of seven studies that aim to add knowledge to the current scientific literature investigating the effects of CWI and provide guidelines to practitioners working with elite athletes.
Study One is a narrative literature review that provides a background to the current scientific knowledge of the recovery modalities implemented in rugby. In this review, CWI was observed to be the most frequently used recovery modality in rugby. In addition, limitations are discussed relating to the methodology of previous studies that have investigated the effects of chronic exposure to CWI. The rational for the acute benefits of CWI as well as the possible harmful effects of chronic CWI implementation are highlighted.
Study Two is a cross-sectional study comparing the usage and perceived effectiveness of different recovery modalities in elite and amateur rugby players. Fifty-eight elite (n = 32) and amateur (n = 26) rugby athletes were surveyed on the usage and perception of 15 different recovery modalities. The elite group perceived active recovery, massage, pool recovery, additional sleep, and stretching to be significantly more effective in comparison to the amateur group. Moreover, the elite group implemented a greater number of recovery modalities and also had a greater frequency of use per week in comparison to the amateur group. The top five recovery modalities in terms of perceived effectiveness were: stretching, cold water immersion, active recovery, additional sleep, and pool recovery in the elite group; and cold water immersion, stretching, contrast baths, additional sleep, and massage in the amateur group.
In Studies Three and Four, acute physiological and perceptual responses were obtained during a training period in elite rugby athletes. In Study Three, a muscle soreness questionnaire was implemented during a nine-day in-season period with 19 elite rugby athletes, to understand if training affected soreness to the same extent at different muscle sites. The muscle soreness questionnaire consisted of soreness ratings from nine different body parts (five lower body and four upper body), from left and right sides. The major finding of this study was that while muscle soreness from the different lower body sites increased on the mornings following training days and the match, the muscle soreness from the upper body sites only increased on the days following a match. Monitoring soreness from different muscle sites, particularly lower body, may provide important information for practitioners. In Study Four, 16 elite rugby athletes were monitored during a non-competitive, in-season training week. The same muscle soreness questionnaire (from Study Three) in conjunction with a wellness questionnaire and a countermovement jump test (Appendix C) were used to monitor fatigue. The wellness questionnaire is commonly used to monitor fatigue and consisted of five questions (sleep quality, general muscle soreness, fatigue, stress, and mood). An effect of training load was observed on the different measures obtained, with this effect being more pronounced following two consecutive training days in comparison to a single training day. As muscle soreness was collected from different muscle sites (i.e. soreness questionnaire) and also from a single question of muscle soreness (i.e. wellness questionnaire), we were able to compare the different measures and conclude that monitoring soreness from different muscle sites may provide important information regarding fatigue, readiness to train, and prevention of injuries.
Study Five was designed to understand the efficacy of CWI in elite rugby athletes. Twenty-three athletes were randomly assigned to a control group (no CWI) or an experimental group (CWI four times per week following the last training session of the day). Acute (i.e. during the training week) and chronic (i.e. over the three-week preseason phase) physiological and perceptual responses of the athletes were monitored. Overall, while the control group demonstrated an increased level of muscle soreness and decreased neuromuscular function (demonstrated by a decrease in the countermovement jump performance) throughout the duration of the study, the athletes exposed to CWI maintained neuromuscular performance and presented lower levels of muscle soreness. Moreover, in the control group, athletes demonstrated an increase in interleukin-6 that was not observed in the CWI group. These findings demonstrate that CWI may provide some beneficial effect by reducing fatigue, soreness, and inflammation within the training week and during an intense three-week pre-season phase.
Study Six, was written to provide practical recommendations to practitioners on the implementation of cold and contrast water modalities. The nature of the cold water modalities was discussed as a more intense cold water modality protocol (e.g. increased immersion duration, decreased water temperature) may be more effective in reestablishing performance, but also may have an increased blunting effect on muscle growth in the chronic setting, based on the manipulated characteristics (i.e. water temperature, exposure time, type, immersion depth). Recommendations and examples were presented regarding the phase of the season, density of the schedule, and athletes’ goals.
In summary, the series of studies in this thesis provide a deeper understanding on the effects of cold water immersion in team-sport athletes in general and rugby in particular. The findings of these studies demonstrate that while rugby training affects athlete performance and other markers associated with fatigue, CWI can be implemented as a strategy to accelerate recovery. These studies add to the current body of knowledge, demonstrating that when rugby athletes are exposed to a dense training week (i.e. four resistance training sessions, seven rugby field sessions, two speed sessions, and four extra-conditioning sessions per week), CWI may attenuate increases in muscle soreness and allow for maintenance of neuromuscular performance. Further research should aim to investigate if the beneficial effects of CWI observed by us outweigh the potential harmful effects on protein synthesis and muscle growth adaptation from training.||