Effects of swimming training on body composition and bone mineral density of prepubertal boys

Abstract

Introduction: It is widely recognized that physical activity has an anabolic effect on bone tissue. However, due to the insufficient information, the exact effect of intensive physical activity in childhood, especially in the prepubescent stage, still remains obscure. It is, therefore, necessary to determine the factors that best produce desired increases in mass and strength of human bones, such as the type, frequency, intensity and duration of the activity. Methods: A group of prepubertal boys was observed in order to examine the effects of swimming training to body composition and bone mineral density. These boys were at the starting point of the peak phase of bone mass development. The group consisted of 58 healthy prepubecent boys, 28 of whom were swimmers (aged 10.8±0.8) and had been practising for 1 year. This was a high level sport training of 10 - 12 hours per week. The other 30 boys were the control group (aged 11.2±0.7) who performed 1.5 hours per week of physical activity at school. Body Fat Analyzer "BES 200 Z" was used in order to evaluate body composition and an ultrasound densitometer "Sahara" was used to measure bone mineral density of the left and right calcaneus. Results: The findings indicate a significant difference between the two groups in respect of the fat mass (p<.03). However, the differences in bone mineral density were not so apparent (p<.67). Conclusion: Kinesiological treatment in swimming, as the results of the study show, is not effective in terms of indecreased bone mineral density parameters.