[Body composition and bone mineral density of prepubertal boys involved in different kinesiologic treatments]

It is well known that physical activity has an anabolic effect on the bone tissue. But there is a lack of information about the effect of intensive physical activity in childhood, particularly at the prepubertal stage. The type, frequency, intensity, and duration of activity that best produce the desired increases in mass and strength of human bones have not yet been well determined.

To examine the influence of different kinesiological treatments on body composition and bone mineral density we studied a group of prepubertal boys at the starting phase of their peak bone mass acquisition. 90 healthy prepubertal boys took part in this study. The sport group consisted of 28 swimmers (aged 10.80.8) and 32 soccer players (aged 10.70.5), who had been training their chosen high-level sport activity for at least 1 year (8-12 h per week for swimmers, 10-15 h per week for soccer players). 30 boys (aged 11.2 +/- 0.7) doing 1.5 h per week of physical activity in school served as a control group. Bone mineral density measurements of the left and right calcaneus were done by ultrasound densitometer "Sahara". The body composition was assessed by Body Fat Analyser "BES 200 Z".

There were significant differences between soccer players and control group as regards fat mass and bone mineral density (p<.01). Besides, significant differences were determined between a group of swimmers and control group as regads fat mass (p<.03), while the differences in bone mineral density were not very obvious (p<.67).