Abstract des Autors

The purpose of this study was to compare the steady rate energy expenditure and heart rate responses with a self-selected exercise intensity during three modes of stationary cycling: upright, legs only (URL); semirecumbent, legs only (SRL); and semirecumbent, arms and legs (SRAL). Subjects (five males, five females) were habituated to each exercise modality and successfully identified similar workloads on different occasions. Each modality was performed for 20 minutes, and steady-rate responses were determined over minutes 11-20. Leg RPM was maintained using a metronome, and oxygen consumption (VO2), heart rate (HR), and rating of perceived exertion (RPE) were continuously monitored. Although HR and VO2 were significantly different across modalities (SRAL>URL>SRL), RPE was not different, indicating selection of similar perceived intensities of exercise. However, there was a disproportionate increase in VO2 relative to HR when SRAL was compared with URL and SRL. Patterns of physiological responses were different between males (SRAL=URL>SRL) and females (SRAL>URL=SRL). Male subjects reported the same RPE across modalities, but there were differences in females RPE (SRAL>URL=SRL). Results of this study revealed that a reduced HR response to stationary cycling in the semirecumbent position is not maintained when arm exercise is added. However, there may be an increased venous return and stroke volume during SRAL, facilitated by the combined effect of the semirecumbent position and the pumping action of the arms. Finally, the physiological demands of SRAL may differ by gender due to upper- and/or lower-body strength differences. Verf.-Referat