Nutrition for sports performance: issues and opportunities.
ABSTRACT Diet can significantly influence athletic performance, but recent research developments have substantially changed our understanding of sport and exercise nutrition. Athletes adopt various nutritional strategies in training and competition in the pursuit of success. The aim of training is to promote changes in the structure and function of muscle and other tissues by selective modulation of protein synthesis and breakdown in response to the training stimulus. This process is affected by the availability of essential amino acids in the post-exercise period. Athletes have been encouraged to eat diets high in carbohydrate, but low-carbohydrate diets up-regulate the capacity of muscle for fat oxidation, potentially sparing the limited carbohydrate stores. Such diets, however, do not enhance endurance performance. It is not yet known whether the increased capacity for fat oxidation that results from training in a carbohydrate-deficient state can promote loss of body fat. Preventing excessive fluid deficits will maintain exercise capacity, and ensuring adequate hydration status can also reduce subjective perception of effort. This latter effect may be important in encouraging exercise participation and promoting adherence to exercise programmes. Dietary supplement use is popular in sport, and a few supplements may improve performance in specific exercise tasks. Athletes must be cautious, however, not to contravene the doping regulations. There is an increasing recognition of the role of the brain in determining exercise performance: various nutritional strategies have been proposed, but with limited success. Nutrition strategies developed for use by athletes can also be used to achieve functional benefits in other populations.
Article: A Comparison of Anthropometric and Training Characteristics between Recreational Female Marathoners and Recreational Female Ironman Triathletes.[show abstract] [hide abstract]
ABSTRACT: A personal best marathon time has been reported as a strong predictor variable for an Ironman race time in recreational female Ironman triathletes. This raises the question whether recreational female Ironman triathletes are similar to recreational female marathoners. We investigated similarities and differences in anthropometry and training between 53 recreational female Ironman triathletes and 46 recreational female marathoners. The association of anthropometric variables and training characteristics with race time was investigated using bi- and multi-variate analysis. The Ironman triathletes were younger (P < 0.01), had a lower skin-fold thickness at pectoral (P < 0.001), axillar (P < 0.01), and subscapular (P < 0.05) site, but a thicker skin-fold thickness at the calf site (P < 0.01) compared to the marathoners. Overall weekly training hours were higher in the Ironman triathletes (P < 0.001). The triathletes were running faster during training than the marathoners (P < 0.05). For the triathletes, neither an anthropometric nor a training variable showed an association with overall Ironman race time after bi-variate analysis. In the multi-variate analysis, running speed during training was related to marathon split time for the Ironman triathletes (P = 0.01) and to marathon race time for the marathoners (P = 0.01). To conclude, although personal best marathon time is a strong predictor variable for performance in recreational female Ironman triathletes, there are differences in both anthropometry and training between recreational female Ironman triathletes and recreational female marathoners and different predictor variables for race performance in these two groups of athletes. These findings suggest that recreational female Ironman triathletes are not comparable to recreational female marathoners regarding the association between anthropometric and training characteristics with race time.The Chinese journal of physiology 02/2013; 56(1):xxx. · 0.56 Impact Factor