Effect Of Martial Arts On Bone Mass Gain In Adolescents: 9 Months Of Follow Up

Sports practice is related to the improvement of bone health in human growth and also during adult life. On the other hand, when the steering gain of bone mass, it is not clear in the literature martial art method is more effective. The objective of this study was to compare bone mass gain after 09 months of follow up in adolescents engaged in different martial arts. This longitudinal study was conducted during 9 months (between 2013 and 2014) with 50 adolescents of both sexes and aged between 11 and 17 years old at baseline. The adolescents were regularly engaged in three martial arts: karate (n= 15), Judo (n= 21) and Kung-Fu (n= 14) and the inclusion criteria were adopted: (i) chronological age between 11 and 17 years-old, (ii) previous authorization of the coach and parents to make part of the study, (iii) at least 6 months of previous practice of the martial art, (iv) no medication use that could affect bone metabolism and (v) signed written consent form. Karate fighters participate in competitions of national level while Judo and Kung-Fu fighters were engaged in championships of regional level. The analyzed outcomes refer to bone mineral content (BMC) [g]) assessed using a dualenergy x-ray absorptiometry scanner (Lunar DPX-NT; General Electric Healthcare) in whole body. Somatic maturation was calculated using the peak of height velocity which denotes the time (years) before/after peak height velocity, which is an important maturational event. Statistical analysis was composed of analysis of covariance (Bonferroni's post-hoc test when necessary), which was adjusted by sex, age, maturation and fat free mass. Measures of effect size were provided by Eta-squared (ES-r). All analyses were procedures performed in the software BioStat (version 5.0). In the comparisons between baseline and follow up measures, there were significant improvements for BMC in all martial arts groups (Karate 9.1% [95%CI: 6.4% to 11.7%]; Judo: 13.1% [95%CI: 10.8% to 15.3%]; Kung-Fu: 7.5% [95%CI: 4.7% to 10.3%]). On the other hand, after adjustment by potential confounders, Judo group presented BMC gains higher than Karate and KungFu. Similar to these findings, previous study identified that Korean adolescents engaged in Judo practice had higher bone mineral density values than control group. After adjustment for potential confounders, Judo group showed greater gains in BMC that Karate and Kung Fu, even with similar biological maturation in martial arts groups, Judo demonstrated largest independent gain Bone Mineral Content of biological maturation.

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