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- Title
Exercise performance and VO2 kinetics during upright and recumbent high-intensity cycling exercise.
- Authors
Egaña, Mikel; O'Riordan, Damien; Warmington, Stuart A.; Egaña, Mikel
- Abstract
This study investigated cycling performance and oxygen uptake V(O)₂kinetics between upright and two commonly used recumbent (R) postures, 65 degrees R and 30 degrees 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 degrees R or 30 degrees 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 +/- 4.5 min) to 65 degrees R (10.5 +/- 2.7 min) and 30 degrees R (11.5 +/- 4.6 min) postures; but it was significantly shorter in the supine posture (5.8 +/- 2.1 min) when compared with the three inclined postures. Resulting kinetic parameters from a tri-exponential analysis of breath-by-breath V(O)₂data 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 approximately 25 mmHg; to 65 degrees R approximately 22 mmHg; and 30 degrees R approximately 18 mmHg such that perfusion of active muscle presumably remains largely unchanged, and also therefore, V(O)₂kinetics and performance during high-intensity cycling.
- Subjects
OXYGEN; FATIGUE (Physiology); SUPINE position; POSTURE; NOBLE gases; OXYGEN metabolism; PHYSIOLOGICAL adaptation; CARDIAC output; COMPARATIVE studies; CYCLING; DYNAMICS; EXERCISE; EXERCISE tests; HEART beat; RESEARCH methodology; MEDICAL cooperation; MUSCLE contraction; PRESSURE; RESEARCH; STATISTICAL sampling; EVALUATION research; OXYGEN consumption; SKELETAL muscle; STROKE volume (Cardiac output); MUSCLE fatigue
- Publication
European Journal of Applied Physiology, 2010, Vol 110, Issue 1, p39
- ISSN
1439-6319
- Publication type
journal article
- DOI
10.1007/s00421-010-1466-y