PURPOSE: The purpose of this study was to investigate the physiological adaptations of resistance training (RT) in prepubertal boys. METHODS:Eighteen healthy boys were divided into RT (n = 9, Mage = 10.4 ± 0.5 years) and control (CTR; n = 9, Mage = 10.9 ± 0.7 years) groups. The RT group underwent a resistance training during 12 weeks, 3 times per week, performing 3 sets of 6 to 15 repetitions at intensities ranging from 60% to 80% of maximal dynamic strength (1-repetition maximum [1-RM] values). Before and after the training, the groups were assessed in their body mass and composition (dual-energy X-ray absorptiometry), isokinetic dynamometry, 1-RM, and ergoespirometry. Moreover, force per unit of muscle volume was calculated by the quotient between 1-RM and lean mass. RESULTS: Both groups presented statistically significant (p < .05) increases in the 1-RM and force per unit of muscle volume in the knee extension and elbow flexion, but these strength increases were statistically significantly greater in the RT group (effect size [ES] = 2.83-9.00) than in the CTR group (ES = 0.72-1.00). Moreover, both groups statistically significantly increased in lean body mass variables (ES = 0.12-0.38). However, increases in the fat mass variables occurred only in the CTR group (ES = - 0.01-0.50), whereas no changes were observed in the RT group. Furthermore, there were statistically significant increases in all bone mineral content variables (ES = 0.13-0.43), without differences between groups. No cardiorespiratory changes were observed. CONCLUSION: Twelve weeks of RT was effective in improving strength and force per unit of muscle volume and prevented fat mass increases in boys.
RCT Entities:
PURPOSE: The purpose of this study was to investigate the physiological adaptations of resistance training (RT) in prepubertal boys. METHODS: Eighteen healthy boys were divided into RT (n = 9, Mage = 10.4 ± 0.5 years) and control (CTR; n = 9, Mage = 10.9 ± 0.7 years) groups. The RT group underwent a resistance training during 12 weeks, 3 times per week, performing 3 sets of 6 to 15 repetitions at intensities ranging from 60% to 80% of maximal dynamic strength (1-repetition maximum [1-RM] values). Before and after the training, the groups were assessed in their body mass and composition (dual-energy X-ray absorptiometry), isokinetic dynamometry, 1-RM, and ergoespirometry. Moreover, force per unit of muscle volume was calculated by the quotient between 1-RM and lean mass. RESULTS: Both groups presented statistically significant (p < .05) increases in the 1-RM and force per unit of muscle volume in the knee extension and elbow flexion, but these strength increases were statistically significantly greater in the RT group (effect size [ES] = 2.83-9.00) than in the CTR group (ES = 0.72-1.00). Moreover, both groups statistically significantly increased in lean body mass variables (ES = 0.12-0.38). However, increases in the fat mass variables occurred only in the CTR group (ES = - 0.01-0.50), whereas no changes were observed in the RT group. Furthermore, there were statistically significant increases in all bone mineral content variables (ES = 0.13-0.43), without differences between groups. No cardiorespiratory changes were observed. CONCLUSION: Twelve weeks of RT was effective in improving strength and force per unit of muscle volume and prevented fat mass increases in boys.
Authors: Margaux J Barnes; Mary K Lynch; Molly D Lisenby; Traci Jester; Jeanine Maclin; Taylor Knight; Gordon Fisher; Barbara Gower Journal: J Pediatr Gastroenterol Nutr Date: 2019-03 Impact factor: 2.839
Authors: David G Behm; James D Young; Joseph H D Whitten; Jonathan C Reid; Patrick J Quigley; Jonathan Low; Yimeng Li; Camila D Lima; Daniel D Hodgson; Anis Chaouachi; Olaf Prieske; Urs Granacher Journal: Front Physiol Date: 2017-06-30 Impact factor: 4.566