Exercise performance and class="latex">class="ss"> [(V)\dot]\textO 2 class="cs">class="math"> \dot{V}{\text{O}}_{ 2} kinetics during upright and recumbent high-intensity cycling
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- 作者：Mikel Ega帽a (1) megana@tcd.ie
Damien O鈥橰iordan (1)
Stuart A. Warmington (2) - 关键词：class="latex">class="ss"> [(V)\dot]\textO 2 class="cs">class="math"> \dot{V}{\text{O}}_{ 2} kinetics ; Recumbent ; Cycling ; Posture ; Performance
- 刊名：European Journal of Applied Physiology
- 出版时间：September 2010
- 出版年：2010
- 期刊代码：80_1439-6319
- 类别：bio
- 卷：110
- 期：1
- 页码：39-47
- 数据来源：sp
摘要
This study investigated cycling performance and oxygen uptake class="latex">class="ss">( [(V)\dot]\textO 2 )class="cs">class="math">( \dot{V}{\text{O}}_{ 2} ) kinetics between upright and two commonly used recumbent (R) postures, 65掳R and 30掳R. On three occasions, ten young active males performed three bouts of high-intensity constant-load (85%peak-workload achieved during a graded test) cycling in one of the three randomly assigned postures (upright, 65掳R or 30掳R). The first bout was performed to fatigue and second and third bouts were limited to 7 min. A subset of seven subjects performed a final constant-load test to failure in the supine posture. Exercise time to failure was not altered when the body inclination was lowered from the upright (13.1 卤 4.5 min) to 65掳R (10.5 卤 2.7 min) and 30掳R (11.5 卤 4.6 min) postures; but it was significantly shorter in the supine posture (5.8 卤 2.1 min) when compared with the three inclined postures. Resulting kinetic parameters from a tri-exponential analysis of breath-by-breath class="latex">class="ss"> [(V)\dot]\textO 2 class="cs">class="math"> \dot{V}{\text{O}}_{ 2} data during the first 7 min of exercise were also not different between the three inclined postures. However, inert gas rebreathing analysis of cardiac output revealed a greater cardiac output and stroke volume in both recumbent postures compared with the upright posture at 30 s into the exercise. These data suggest that increased cardiac function may counteract the reduction of hydrostatic pressure from upright ~25 mmHg; to 65掳R ~22 mmHg; and 30掳R ~18 mmHg such that perfusion of active muscle presumably remains largely unchanged, and also therefore, class="latex">class="ss"> [(V)\dot]\textO 2 class="cs">class="math"> \dot{V}{\text{O}}_{ 2} kinetics and performance during high-intensity cycling.