Explaining the Maximal Intensity Exercise Performance of Young People

探索兒童最大強度運動能力

Abstract

LANGUAGE NOTE | Document text in English; abstract also in Chinese.

Explanations for children maximal intensity exercise fitness in the literature fluctuate between the incapacity of young children to generate energy anaerobically and a reduced need for the metabolic pathway. A number of propositions are advanced to explain young children's relative inaptitude in anaerobic performance in comparison with older children and adults. These range from a smaller quantity of active muscle mass to perform the anaerobic task, to the quality of the muscle which may not yet be energetically, chemically or neurogenically mature, in comparison to their older and more mature counterparts. No one single factor, whether quantitative or qualitative in nature, however, can account exclusively for the anaerobic fitness of young people. The other persuasive argument advanced is that children are less reliant than adults on the anaerobic energy pathway, for their energy supply. Arguments supporting such a contention include a swifter oxygen uptake response in children during high intensity exercise, a greater blood flow to muscle and greater oxygen extraction capability, and a blunted response to catecholamines during high intensity exercise. Either way, the evidence in the current literature is equivocal. Future research employing the use of non-invasive methods such as MRI to determine muscle fibre type, MRS to determine baseline energy substrates and utilisation rates during exercise, as well as mass spectroscopy to analyse oxygen uptake kinetics and other ventilatory responses during high intensity exercise, may help bring to the fore new knowledge to a most interesting area of research in children's exercise.

有關兒童最大強度運動能力的文獻報導結果不一。有些學者認為兒童的無氧代謝的能力非常低下，而有些學者則認為是因為兒童對無氧代謝的需求較低。一些文獻闡述了年幼兒童無氧代謝能力較少年或成人低下的原因是由於肌肉的數量，尤其是無氧代謝能力較強的肌肉數量較少以及肌肉在能量代謝、生物化學和神經支配方面的成熟度較成年人低。而僅以某一單一因素，無論是肌肉數 量還是成熟度，都不足以解釋兒童無氧代謝能力的特點。另一些研究則表明兒童對無氧供能的需求量較成年人低，主要表現在兒童進行大強度運動時其攝氧量急劇上升，肌肉的血流量和氧攝取量明顯增加，以及運動中對兒茶酚胺的反應不敏感等。然而，迄今為 止對於兒童最大強度運動能力的特點仍不十分清楚，需作進一步的研究。應用無創傷性方法，如應用核磁共振成像法檢測肌纖維類 型、核磁共振光譜分析法測定運動中的能量物質及其利用率，以及質譜法分析大強度運動過程中攝氧量的動態變化和通氣量的變化 等，則將有助於提高和促進兒童體育科學研究。