Sabapathy Surendran, Schneider Donald A, Comadira Greg, Johnston Iain, Morris Norman R
School of Physiotherapy and Exercise Science, Griffith University, PMB 50 Gold Coast Mail Centre, Gold Coast, Qld. 9726, Australia.
Respir Physiol Neurobiol. 2004 Jan 15;139(2):203-13. doi: 10.1016/j.resp.2003.09.008.
This study examined the relationship between the slow component of oxygen uptake (VO2) kinetics and muscle electromyography (EMG) during severe exercise in nine young (21.7+/-0.9 yr) and nine older (71.6+/-0.8 yr) men. Oxygen uptake (VO2) and surface EMG activity of the left vastus lateralis muscle were measured during a 7-min square-wave bout of severe exercise on a cycle ergometer. The absolute amplitude of the VO2 slow component was greater and occurred approximately 60 s earlier in the young compared to older subjects. However, the rate of increase in the slow component, expressed as a percentage of the total VO2 response per unit time, was not different between young and older subjects (young: 4.8+/-0.5%.min(-1); older: 4.9+/-0.6%.min(-1)). The mean power frequency (MPF) of the EMG increased significantly during the slow component phase of exercise by 6.4+/-1.0% in the young and by 5.4+/-0.7% in the older group and this rise was not significantly different between the two groups. These results indicate that normal ageing may not alter the VO2 slow component (measured as the rate of increase in VO2) and that this finding may be related to similar muscle fibre recruitment patterns in the two groups during severe-intensity exercise.
本研究调查了9名年轻男性（21.7±0.9岁）和9名老年男性（71.6±0.8岁）在剧烈运动期间摄氧量（VO2）动力学的慢成分与肌肉肌电图（EMG）之间的关系。在自行车测力计上进行7分钟的剧烈运动方波试验期间，测量了左侧股外侧肌的摄氧量（VO2）和表面肌电活动。与老年受试者相比，年轻受试者VO2慢成分的绝对幅度更大，且出现时间早约60秒。然而，以单位时间内总VO2反应的百分比表示的慢成分增加速率，在年轻和老年受试者之间并无差异（年轻：4.8±0.5%·min⁻¹；老年：4.9±0.6%·min⁻¹）。运动慢成分阶段，年轻组肌电的平均功率频率（MPF）显著增加6.4±1.0%，老年组增加5.4±0.7%，两组间的这种增加无显著差异。这些结果表明，正常衰老可能不会改变VO2慢成分（以VO2增加速率衡量），这一发现可能与两组在高强度运动期间相似的肌纤维募集模式有关。
