Pokan R, Schwaberger G, Hofmann P, Eber B, Toplak H, Gasser R, Fruhwald F M, Pessenhofer H, Klein W
Department of Internal Medicine, Karl Franzens University, Graz, Austria.
Int J Sports Med. 1995 May;16(4):238-42. doi: 10.1055/s-2007-972998.
In order to investigate the effect of an exercise protocol on the levelling-off O2 uptake and VO2 max values, ten male subjects aged 28 +/- 5 yrs, height 1.8 +/- 0.05 m, body mass 76 +/- 6 kg performed two treadmill exercise protocols: 1) constant grade (CG) of 5%, with increasing running speed starting at 6 km.h-1 and increments of 2 km.h-1 every 3 minutes. 2) ascending grade (AG) starting at 0% and increments of 5% every 3 minutes, with constant running speed of 5 km.h-1. During each protocol oxygen uptake (VO2), pulmonary ventilation (VE), tidal volume (Vt), and breathing rate (BR) as well as blood lactate concentration (La) and heart rate (HR) were measured. In CG a levelling-off phenomenon of VO2 in all cases was observed. Aerobic capacity expressed as VO2 max in CG was 46.2 +/- 6.0 ml.min-1.kg-1. In contrast, VO2 max was 35% higher in AG (62.6 +/- 7.2 ml.min-1.kg-1). The behaviour of VO2 indicates a lower efficiency with increasing work load in AG as compared to CG. Regarding maximum performance it can be concluded that VO2 in CG seems to be limited by a mechanical or neuromuscular constraint on the depth of breathing, which is confirmed by a distinct flattening of Vt. The levelling-off of the VO2 in CG, something which is not observed in AG, can be explained plausibly this way.
为了研究一种运动方案对氧摄取平稳状态和最大摄氧量（VO₂max）值的影响，10名年龄在28±5岁、身高1.8±0.05米、体重76±6千克的男性受试者进行了两种跑步机运动方案：1）恒定坡度（CG）为5%，跑步速度从6千米/小时开始增加，每3分钟增加2千米/小时。2）递增坡度（AG）从0%开始，每3分钟增加5%，跑步速度恒定为5千米/小时。在每个方案期间，测量了氧摄取量（VO₂）、肺通气量（VE）、潮气量（Vt）、呼吸频率（BR）以及血乳酸浓度（La）和心率（HR）。在CG方案中，所有情况下均观察到VO₂的平稳状态现象。以VO₂max表示的CG方案中的有氧能力为46.2±6.0毫升·分钟⁻¹·千克⁻¹。相比之下，AG方案中的VO₂max高35%（62.6±7.2毫升·分钟⁻¹·千克⁻¹）。VO₂的表现表明，与CG方案相比，AG方案中随着工作负荷增加效率较低。关于最大运动能力，可以得出结论，CG方案中的VO₂似乎受到呼吸深度的机械或神经肌肉限制，这一点通过Vt明显变平得到证实。CG方案中VO₂的平稳状态（AG方案中未观察到）可以用这种方式得到合理的解释。
