McCully K, Posner J
Department of Geriatric Medicine, Medical College Hospitals, Philadelphia, PA 19129.
Int J Sports Med. 1992 Oct;13 Suppl 1:S147-9. doi: 10.1055/s-2007-1024621.
We compared the metabolic capacity of calf muscles in young normal subjects who performed endurance training to highly trained track athletes, older subjects, and subjects with several metabolic diseases. Metabolic capacity was measured as the rate of phosphocreatine (PCr) recovery following submaximal exercise. PCr levels were measured using magnetic resonance spectroscopy (MRS). Exercise consisted of repeated plantar flexion against resistance. MRS calculated metabolic capacity agreed well with rates from muscle biopsies. Short term endurance training resulted in a 14% increase in metabolic capacity. This adaptation was small compared to the metabolic capacities of endurance athletes (70% greater than control subjects), and changes due to aging (20% and 55% declines by 66 and 80 years of age, respectively). Exercise training is also associated with muscle injury. Muscle injury was seen as a transient elevation of Pi/PCr at rest in response to an acute bout of exercise. The elevation of resting Pi/PCr persisted during continued training. Metabolic capacity as measured by the rate of phosphocreatine recovery increased with endurance training and decreased with normal aging and metabolic disease. Small levels of persistent muscle injury is a natural by product of strenuous endurance training.
我们比较了进行耐力训练的年轻正常受试者、训练有素的田径运动员、老年受试者以及患有多种代谢疾病的受试者小腿肌肉的代谢能力。代谢能力通过次最大运动后磷酸肌酸（PCr）的恢复率来衡量。PCr水平使用磁共振波谱（MRS）进行测量。运动包括重复进行抗阻跖屈。MRS计算得出的代谢能力与肌肉活检的结果高度一致。短期耐力训练使代谢能力提高了14%。与耐力运动员的代谢能力相比（比对照组高70%），这种适应性变化较小，且与衰老导致的变化（66岁和80岁时分别下降20%和55%）相比也较小。运动训练还与肌肉损伤有关。肌肉损伤表现为在一次急性运动后静息状态下Pi/PCr的短暂升高。在持续训练期间，静息Pi/PCr的升高持续存在。通过磷酸肌酸恢复率衡量的代谢能力随耐力训练而增加，随正常衰老和代谢疾病而降低。少量持续性肌肉损伤是剧烈耐力训练的自然副产品。
