Children's Health and Exercise Research Centre, School of Sport and Health Sciences, University of Exeter, Exeter, United Kingdom.
Med Sci Sports Exerc. 2010 Jul;42(7):1303-13. doi: 10.1249/MSS.0b013e3181cabaeb.
This study tested the hypothesis that the muscle metabolic responses of 9- to 12-yr-old children and young adults during incremental quadriceps exercise are dependent on age and sex.
Fifteen boys, 18 girls, 8 men, and 8 women completed a quadriceps step-incremental test to exhaustion inside a magnetic resonance scanner for determination of the muscle metabolic responses using P-magnetic resonance spectroscopy. Quadriceps muscle mass was determined using magnetic resonance imaging scans enabling comparison of metabolic data at a normalized power output.
The power output and the energetic state at the Pi/PCr and pH intracellular thresholds (IT) were independent of age and sex. The rate of change in Pi/PCr against power output after the ITPi/PCr (S2) was lower in boys (0.158 +/- 0.089) and girls (0.257 +/- 0.110) compared with men (0.401 +/- 0.114, P < 0.001) and women (0.391 +/- 0.133, P = 0.014), respectively, with sex differences present for children only (P = 0.003). Above the ITpH, S2 was more rapid in the men (-0.041 +/- 0.022, P = 0.003) and girls (-0.030 +/- 0.013, P = 0.011) compared with boys (-0.019 +/- 0.007), with no differences between the girls and the women (-0.035 +/- 0.015, P = 0.479). The increase in Pi/PCr at exhaustion was lower in boys (0.85 +/- 0.38) than that in men (1.86 +/- 0.65, P < 0.001) and in girls (1.78 +/- 1.25) than that in women (4.97 +/- 3.52, P = 0.003), with sex differences in both the child (P = 0.005) and the adult groups (P = 0.019).
During moderate-intensity exercise, muscle metabolism appears adult-like in 9- to 12-yr-old children, although both age- and sex-related differences in the "anaerobic" energy turnover are present during high-intensity exercise.
本研究旨在检验以下假设，即在递增式股四头肌运动中，9-12 岁儿童和年轻成年人的肌肉代谢反应取决于年龄和性别。
15 名男孩、18 名女孩、8 名男性和 8 名女性在磁共振扫描仪内完成股四头肌步进递增测试，以使用 P-磁共振光谱法确定肌肉代谢反应。通过磁共振成像扫描确定股四头肌质量，从而可以在标准化功率输出下比较代谢数据。
功率输出和 Pi/PCr 及细胞内 pH 值 IT 处的能量状态与年龄和性别无关。在 Pi/PCr 之后，Pi/PCr 与功率输出的变化率（S2）在男孩（0.158 ± 0.089）和女孩（0.257 ± 0.110）中低于男性（0.401 ± 0.114，P < 0.001）和女性（0.391 ± 0.133，P = 0.014），且仅在儿童中存在性别差异（P = 0.003）。在 ITpH 以上，S2 在男性（-0.041 ± 0.022，P = 0.003）和女孩（-0.030 ± 0.013，P = 0.011）中比男孩（-0.019 ± 0.007）更快，而女孩和女性之间没有差异（-0.035 ± 0.015，P = 0.479）。男孩在运动结束时 Pi/PCr 的增加（0.85 ± 0.38）低于男性（1.86 ± 0.65，P < 0.001）和女孩（1.78 ± 1.25）高于女性（4.97 ± 3.52，P = 0.003），且在儿童和成年人群中都存在性别差异（P = 0.005 和 P = 0.019）。
在中等强度运动中，9-12 岁儿童的肌肉代谢似乎与成年人相似，尽管在高强度运动中仍存在与年龄和性别相关的“无氧”能量转换差异。
