Abstract
Increases in cadence may augment SV during submaximal cycling (> 65% V̇O2max) via effects of increased muscle pump activity on preload. At lower workloads (45-65% V̇O2max), SV tends to plateau, suggesting that effects of increases in cadence on pump activity have little influence on SV. We hypothesized that cadence-induced increases in CO at submaximal workloads, where SV tends to plateau, are due to elevations in HR and/or O2 extraction. SV, CO, HR, V̇O2, and Δa-vO2 were assessed at 80 and 100 rpm during workloads of 50% (LO) or 65% (HI) of V̇O2max in 11 male cyclists. No changes in SV were seen. CO was higher at 100 rpm in 10 of 11 subjects at LO (18.1 ± 2.7 vs. 17.2 ± 2.6 L/min). V̇O2 at both workloads was greater at 100 than 80 rpm as was HR (LO: 129 ± 11 vs. 121 ± 10 beats/min; HI: 146 ± 13 vs. 139 ± 14 beats/min) (p < 0.05). Δa-vO2 was greater at HI compared to LO at 80 (15.1 ± 1.6 vs. 13.6 ± 1.3 ml) and 100 rpm (16.0 ± 1.7 vs. 15.1 ± 1.6 ml) (p < 0.05). Results suggest that increases in O2 demand during low submaximal cycling (50% V̇O2max) at high cadences are met by HR-induced increases in CO. At higher workloads (65% V̇O 2max), inability of higher cadences to increase CO and O2 delivery is offset by greater O2 extraction.
Original language | English (US) |
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Pages (from-to) | 116-119 |
Number of pages | 4 |
Journal | International Journal of Sports Medicine |
Volume | 29 |
Issue number | 2 |
DOIs | |
State | Published - Feb 2008 |
Keywords
- Arterial-venous oxygen difference
- Cadence
- Cardiac output
- Cycling
- Heart rate
- Stroke volume
ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation