The impact of cryotherapy versus placebo interventions on recovery following strenuous exercise, and adaptations to resistance training

Strenuous exercise leads to muscle soreness, decrements in muscle function, and increases in circulating intracellular proteins and inflammatory markers. The magnitude of change and time course of recovery of these symptoms is largely dependent upon exercise mode. Cryotherapy, (cold water immersion (CWI) or whole body cryotherapy (WBC)), is commonly utilised in an attempt to minimise the negative impact of these symptoms on subsequent performance. Although WBC is becoming increasingly popular, there remains a lack of literature comparing CWI and WBC following ecologically valid exercise stresses and research suggests that reported beneficial effects may be attributed to the placebo effect. Furthermore, there is a need to examine the impact of repeated cryotherapy exposure on adaptations to training. Therefore, the aim of this thesis was to compare the effectiveness of CWI, WBC and placebo interventions on acute recovery following endurance and resistance exercise, and to examine the impact of habitual CWI on adaptations to a resistance training programme. The acute studies demonstrated that cryotherapy was more effective than a placebo for attenuating increases in muscle soreness. Whilst there was no difference in soreness between CWI and WBC following endurance exercise, WBC was superior to CWI following resistance exercise. Neither cryotherapy intervention was more effective than a placebo for recovery of functional markers following endurance or resistance exercise. Importantly, cryotherapy appeared to exacerbate rather than attenuate the inflammatory response following both exercise modes compared to a placebo. When used as an adjunct to a resistance training programme, CWI did not attenuate soreness over time, and diminished increases in muscle fibre pennation angle compared to a placebo. CWI may have enhanced neural adaptations, although there were no clear functional improvements compared to placebo. Lastly, decrements in markers of bone and collagen turnover were more pronounced in the CWI group. These findings indicate that cryotherapy is no more effective than a placebo intervention for functional recovery or the attenuation of inflammation following acute endurance or resistance exercise. Furthermore, whilst CWI may enhance neural adaptations to resistance training, repeated exposure may result in maladaptive hypertrophic responses.