Coggan A R, Spina R J, Rogers M A, King D S, Brown M, Nemeth P M, Holloszy J O
Section of Applied Physiology, Washington University School of Medicine, St. Louis, Missouri 63110.
J Appl Physiol (1985). 1990 May;68(5):1896-901. doi: 10.1152/jappl.1990.68.5.1896.
Many older athletes are capable of endurance performances equal to those of young runners who have higher maximal O2 uptakes (VO2max). To determine whether this is a result of differences in skeletal muscle characteristics, gastrocnemius muscle biopsy samples were obtained from eight master athletes [aged 63 +/- 6 (SD) yr] and eight young (aged 26 +/- 3 yr) runners. The young runners were matched with the master athletes for 10-km running performance and for their volume, pace, and type of training. Despite similar 10-km run times, VO2max was 11% lower (P less than 0.05) in the master athletes. Fiber type distribution did not differ between groups, with both groups having 60% type I and very few type IIb fibers. Succinate dehydrogenase and beta-hydroxyacyl-CoA dehydrogenase activities, however, were 31 and 24% higher in the master athletes compared with the matched young runners, whereas lactate dehydrogenase activity was 46% lower (all P less than 0.05). The capillary-to-fiber ratio was also greater in the master athletes; however, capillary density was similar in the two groups, because of the master athletes' 34% larger (P less than 0.05) type I fibers. These differences in skeletal muscle characteristics may explain the master athletes' ability to perform as well as some young runners despite having a lower VO2max.
许多年长的运动员能够取得与最大摄氧量（VO2max）较高的年轻跑步者相当的耐力成绩。为了确定这是否是骨骼肌特征差异的结果，从8名老年运动员[年龄63±6（标准差）岁]和8名年轻（年龄26±3岁）跑步者身上获取了腓肠肌活检样本。年轻跑步者在10公里跑步成绩、训练量、配速和训练类型方面与老年运动员相匹配。尽管10公里跑步时间相似，但老年运动员的VO2max低11%（P<0.05）。两组之间的纤维类型分布没有差异，两组均有60%的I型纤维且几乎没有IIb型纤维。然而，与相匹配的年轻跑步者相比，老年运动员的琥珀酸脱氢酶和β-羟酰基辅酶A脱氢酶活性分别高31%和24%，而乳酸脱氢酶活性低46%（所有P<0.05）。老年运动员的毛细血管与纤维比率也更高；然而，两组的毛细血管密度相似，因为老年运动员的I型纤维大34%（P<0.05）。骨骼肌特征的这些差异可能解释了老年运动员尽管VO2max较低，但仍能与一些年轻跑步者表现相当的能力。
