A carga de treinamento semanal e o tempo anterior de envolvimento na modalidade esportiva foram relatados pelo treinador. Go to: Introduction During adulthood, bone health is affected by physical inactivity and aging, since both affect bone structure and can lead to osteoporosis and fractures.
During childhood and adolescence growth hormone contributes to bone mass gain and the concentration of this hormone in the blood is increased by physical exercise. We hypothesized that martial arts practice would be related to higher BMD in adolescents of both sexes. The cohort study "Practice of different sport modalities and bone mass gain in adolescents: cohort of 9 months" was conducted during and and the presented data forms part of the baseline measures.
Sample size estimation was performed using an equation based on analysis of variance ANOVA , which took into account a minimum difference for BMD of 0. Final sample size was estimated as a minimum of 12 adolescents per group and, therefore, at least 48 adolescents were required. For adolescents engaged in martial arts, the following criteria were included: i aged between 11 and 17; ii a minimum of 03 months of previous involvement in the current martial art and iii the coach's permission.
Adolescents of both sexes, engaged in martial arts regional level , were recruited from sport clubs in different regions of the city as follows: Karate 9 girls and 5 boys [Shotokan style] , Judo 8 girls and 10 boys and Kung-fu 1 girl and 15 boys [sanda style]. The control group was composed of adolescents from five schools located in different regions of the city.
The parents or guardians signed a written consent form and the study had been previously approved by the Ethical Board of the Sao Paulo State University Campus of Presidente Prudente, Brazil. Body weight was measured using a digital scale Filizzola, Sao Paulo, Brazil, to the nearest 0. All anthropometric measurements were performed following previously published standard methods.
