Turner D L, Hoppeler H, Claassen H, Vock P, Kayser B, Schena F, Ferretti G
Department of Anatomy, University of Bern, Switzerland.
Acta Physiol Scand. 1997 Dec;161(4):459-64. doi: 10.1046/j.1365-201X.1997.00246.x.
Six healthy subjects performed endurance training of the same duration with legs and arms consecutively. Performance and muscle structure were measured before and after training in lower and upper limbs. Training induced similar increases in maximal oxygen consumption (6 +/- 1 vs. 7 +/- 2 mL min-1 kg-1: legs vs. arms, P > 0.05) and mitochondrial volume in leg and arm muscles (42 +/- 12 vs. 31 +/- 11%: legs vs. arms, P > 0.05). The gain in mitochondrial volume after training was achieved solely by increasing the fraction of mitochondria (+40 +/- 11%, P < 0.05) in the same muscle volume (+2 +/- 2%, P > 0.05) in the legs. In contrast, increased muscle volume (+14 +/- 3%, P < 0.05), in addition to a tendency for an increase in mitochondrial fraction (+16 +/- 11%, P > 0.05), occurred in the arms after training. Thus, similar improvements in muscle oxidative capacity in upper and lower limbs were brought about by different mechanisms. It is suggested that due to infrequent use and a lack of load-bearing function, arm muscle volume is underdeveloped in untrained, sedentary or detrained/injured subjects and that the mode of endurance training used in this study is sufficient to enlarge arm muscle volume as well as aerobic capacity.
六名健康受试者先后对腿部和手臂进行了相同时长的耐力训练。在训练前后分别测量了下肢和上肢的运动表现及肌肉结构。训练使腿部和手臂肌肉的最大耗氧量（腿部：6±1 vs. 手臂：7±2 mL·min⁻¹·kg⁻¹，P>0.05）和线粒体体积出现了相似程度的增加（腿部：42±12 vs. 手臂：31±11%，P>0.05）。训练后腿部线粒体体积的增加完全是通过增加同一肌肉体积中线粒体的比例（+40±11%，P<0.05）实现的，而肌肉体积增加幅度较小（+2±2%，P>0.05）。相比之下，训练后手臂除了线粒体比例有增加的趋势（+16±11%，P>0.05）外，肌肉体积也有显著增加（+14±3%，P<0.05）。因此，上肢和下肢肌肉氧化能力的相似改善是由不同机制引起的。研究表明，由于使用频率低且缺乏承重功能，未经训练、久坐不动或失训/受伤的受试者手臂肌肉体积发育不足，而本研究中使用的耐力训练模式足以增大手臂肌肉体积以及有氧能力。
