Phillips Stuart M
Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
Nutrition. 2004 Jul-Aug;20(7-8):689-95. doi: 10.1016/j.nut.2004.04.009.
Daily requirements for protein are set by the amount of amino acids that is irreversibly lost in a given day. Different agencies have set requirement levels for daily protein intakes for the general population; however, the question of whether strength-trained athletes require more protein than the general population is one that is difficult to answer. At a cellular level, an increased requirement for protein in strength-trained athletes might arise due to the extra protein required to support muscle protein accretion through elevated protein synthesis. Alternatively, an increased requirement for protein may come about in this group of athletes due to increased catabolic loss of amino acids associated with strength-training activities. A review of studies that have examined the protein requirements of strength-trained athletes, using nitrogen balance methodology, has shown a modest increase in requirements in this group. At the same time, several studies have shown that strength training, consistent with the anabolic stimulus for protein synthesis it provides, actually increases the efficiency of use of protein, which reduces dietary protein requirements. Various studies have shown that strength-trained athletes habitually consume protein intakes higher than required. A positive energy balance is required for anabolism, so a requirement for "extra" protein over and above normal values also appears not to be a critical issue for competitive athletes because most would have to be in positive energy balance to compete effectively. At present there is no evidence to suggest that supplements are required for optimal muscle growth or strength gain. Strength-trained athletes should consume protein consistent with general population guidelines, or 12% to 15% of energy from protein.
蛋白质的每日需求量是由特定一天中不可逆损失的氨基酸量来确定的。不同机构已经为普通人群设定了每日蛋白质摄入量的需求水平；然而，力量训练运动员是否比普通人群需要更多蛋白质这个问题很难回答。在细胞层面，力量训练运动员对蛋白质需求的增加可能是由于通过提高蛋白质合成来支持肌肉蛋白质积累所需的额外蛋白质。或者，这组运动员对蛋白质需求的增加可能是由于与力量训练活动相关的氨基酸分解代谢损失增加。一项使用氮平衡方法研究力量训练运动员蛋白质需求的综述表明，该组运动员的需求量有适度增加。与此同时，多项研究表明，力量训练由于其提供的蛋白质合成合成代谢刺激，实际上提高了蛋白质的利用效率，从而降低了膳食蛋白质需求。各种研究表明，力量训练运动员习惯性地摄入高于所需量的蛋白质。合成代谢需要正能量平衡，所以对于竞技运动员来说，超出正常值的“额外”蛋白质需求似乎也不是一个关键问题，因为大多数运动员为了有效参赛必须处于正能量平衡状态。目前没有证据表明为了实现最佳肌肉生长或力量增长需要补充剂。力量训练运动员应按照普通人群的指导方针摄入蛋白质，即蛋白质提供的能量占总能量的12%至15%。
