The effects of cryotherapy on proprioception, indices of muscle damage and on intramuscular, skin and core temperature

Cryotherapy, the therapeutic use of cold, has been used since the time of the ancient Greeks. In sport medicine, whole body cooling is used before and after athletic participation. Pre-cooling before exercise enables an individual to start exercise with a cooler body temperature, increase their heat storage capacity and perform more work before reaching a limiting core body temperature. Cryotherapy is also used after exercise in an attempt to alleviate the debilitating effects of exercise induced muscle damage. Cold Water Immersion (CWI) is one of the most commonly used modalities of cooling in sports medicine. CWI involves immersing an individual in cold water to the level of the waist or sternum. Whole Body Cryotherapy (WBC) is a relatively new modality of cooling that involves exposing an individual to extremely low temperatures for a short duration of time in a specially built cryogenic chamber. The physiological effects of whole body cooling, especially WBC, are poorly understood and the potential negative effects of pre-cooling on proprioceptive acuity have not been elucidated. Furthermore, the purported benefits of using WBC as a treatment for exercise induced muscle damage have not been evaluated. This thesis comprises 5 papers (2 reviews and 3 controlled studies) which investigate the physiological effects of whole body cooling. As it has been hypothesised that a reduction in Joint Position Sense (JPS) may reduce athletic performance or predispose injury, particular emphasis is paid to the effects of these modalities on JPS. Therefore, the primary aim was to explore the effects of CWI and WBC on proprioceptive acuity and to compare and contrast the ability of both cooling modalities to reduce muscle, skin and core temperature. A secondary aim of this thesis was to assess the effectiveness of WBC as a method of recovery following symptoms of exercise induced muscle damage. In summary the findings of this thesis suggest that knee JPS is not reduced following CWI or WBC. In addition WBC did not reduce muscle force (maximal voluntary isometric contraction of the knee extensors) or force proprioception. The cooling potential of CWI and WBC on muscle, skin and core temperature was investigated using a randomised crossover design. A comparable reduction in muscle and core temperature was observed, however skin temperature was lower immediately after WBC compared to CWI. Finally, when administered 24 hours after eccentric exercise, WBC appears to be ineffective in alleviating muscle soreness or enhancing muscle force recovery. The results and conclusions presented in this thesis may contribute to overall understanding of whole body cooling; inform clinicians and sports people and direct future research in the area.