Thermoregulation during soccer specific intermittent exercise : the effects of clothing and environment
Team sports such as soccer follow an intermittent pattern of exercise, which is known to place greater demands on thermoregulation than continuous exercise of a similar intensity. Time to exhaustion has been shown to be dependent upon environmental temperature, while clothing is known to create a microenvironment at the surface of the skin. The aim of this thesis was to determine the thermoregulatory response to soccer-specific intermittent exercise during different conditions of clothing and environment. The thermal and physiological responses of the feet to continuous and soccer-specific intermittent exercise were evaluated. Intermittent exercise was found to induce an increase in foot skin temperature of a greater magnitude than during continuous exercise of the same overall intensity- The findings indicate that the foot maintains an altered thermoregulatory response not evident elsewhere on the human body. The localised and whole-body physiological and thermal responses to soccer footwear were examined during soccer-specific intermittent exercise. Soccer footwear does not have a significantly detrimental effect on physiological responses compared to training shoes. Nevertheless, there was evidence of increased thermal strain when wearing the soccer boot, which may become significant in a hot environment. Similarly, the localised and whole-body physiological and thermal responses of the hands were evaluated when wearing goal keeping gloves during simulated goalkeeper activity- Goalkeepers' gloves restrict heat loss from the hand and in order to alleviate this problem, phase control materials (PCM's) have been developed to reduce heat load and maintain a comfortable skin temperature. All sites of skin measurement, except mean body skin temperature, showed uniformly that a PCM glove caused a greater increase in skin temperature than a glove with normal foam material. Therefore, the particular specification of PCM used in this study promoted heat gain rather than the intended heat loss and was therefore inappropriate to enhance thermal comfort when used in a goalkeeper's glove. The effects of three different environmental conditions (10°C, 20°C and 30°C) on soccer-specific intermittent exercise were examined, Results showed that the physiological strain-associated with soccer-specific intermittent exercise is greatest in the heat (30°C) with parameters such as heart rate, mean skin temperature, rating of perceived exertion, thermal perception, change in body mass and skin blood flow all lowest during exercise in the cool. Exercise in the cool condition (10°C) may be the optimal environment for performance of soccer-specific intermittent exercise, A significant relation was found between core temperature and prolactin (marker of brain serotonin activity) suggesting that central serotinergic mechanisms of fatigue may play a role in exercise performance during soccer-specific intermittent activity performed in the heat. The effects of traditional soccer fabrics and technical fabrics on the physiological and thermoregulatory responses to soccer-specific intermittent exercise were evaluated. Analysis revealed that slight differences between traditional and technical clothing ensembles in physiological parameters, such as heart rate, mean skin temperature, body mass loss and rating of perceived exertion, were not significant. Therefore, wearing technical fabric clothing gives no particular benefit over a traditional fabric ensemble. In The lack of differences between clothing materials lead to the conclusion that an elite soccer team competing under extremes of temperature in international climates would be best advised to concentrate on proper acclimatisations nutrition and fluid replacement strategies prior to competition than on the specifics of clothing design.