Gonzales Joaquin U, Scheuermann Barry W
Department of Kinesiology, The University of Toledo, Toledo, OH 43607, USA.
J Electromyogr Kinesiol. 2008 Feb;18(1):99-107. doi: 10.1016/j.jelekin.2006.09.002. Epub 2006 Oct 24.
The aim of this study was to test the hypothesis that prior heavy exercise results in a higher oxygen cost during a subsequent bout of moderate exercise due to changes in muscle activity. Eight male subjects (25+/-2 yr, +/-SE) performed moderate-moderate and moderate-heavy-moderate transitions in work rate (cycling intensity, moderate=90% LT, heavy=80% VO(2) peak). The second bout of moderate exercise was performed after 6 min (C) or 30s (D) of recovery. Pulmonary gas exchange was measured breath-by-breath and surface electromyography was obtained from the vastus lateralis and medialis muscles. Root mean square (RMS) and median power frequency (MDPF) were computed. Prior heavy exercise increased DeltaVO(2)/DeltaWR (C: +2.0+/-0.8 ml min(-1)W(-1), D: +3.4+/-0.8 ml min(-1)W(-1); P<0.05) and decreased exercise efficiency (C: -13.3+/-5.6%, D: -22.2 +/-4.9%; P<0.05) during the second bout of moderate exercise in the absence of changes in RMS. MDPF was slightly elevated ( approximately 2%) during the second bout of moderate exercise, but MDPF was not correlated with V O(2) (r=0.17). These findings suggest that the increased oxygen cost during moderate exercise following heavy exercise is not due to increased muscle activity as assessed by surface electromyography.
由于肌肉活动的变化，先前的高强度运动会导致随后进行的中等强度运动期间的氧消耗增加。八名男性受试者（25±2岁，±标准误）在工作率（骑行强度，中等强度=90%乳酸阈，高强度=80%最大摄氧量峰值）方面进行了中等强度-中等强度和中等强度-高强度-中等强度的转换。第二次中等强度运动在恢复6分钟（C组）或30秒（D组）后进行。逐次测量肺气体交换，并从股外侧肌和股内侧肌获取表面肌电图。计算均方根（RMS）和中位功率频率（MDPF）。在第二次中等强度运动期间，在RMS无变化的情况下，先前的高强度运动增加了ΔVO₂/ΔWR（C组：+2.0±0.8 ml·min⁻¹·W⁻¹，D组：+3.4±0.8 ml·min⁻¹·W⁻¹；P<0.05）并降低了运动效率（C组：-13.3±5.6%，D组：-22.2±4.9%；P<0.05）。在第二次中等强度运动期间，MDPF略有升高（约2%），但MDPF与VO₂不相关（r=0.17）。这些发现表明，高强度运动后中等强度运动期间氧消耗的增加并非由于表面肌电图评估的肌肉活动增加。
