Received November 15, 2005
Revised December 15, 2005
Accepted after revision March 6, 2006
Human, Environmental & Exercise [250]
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The critical power-oxygen uptake relation at different pedaling frequencies
Tyler Barker 1,
David Poole 2,
Larry Noble 2,
Thomas Barstow 2*
1 The Orthopedic Speciality Hospital, and Oregon State University
2 Kansas State University
* To whom correspondence should be addressed. E-mail: tbarsto{at}ksu.edu.
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Abstract |
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Critical power (CP) is lower at faster rather than slower pedaling frequencies and traditionally reported in watts (W). Faster pedaling frequencies also engender a greater metabolic rate (V.O2) at low work rates, but with progressive increases in power output, the initial difference in V.O2 between fast and slower pedaling frequencies is reduced. We tested the hypothesis that CP represents a unique metabolic rate for any given individual which would be similar at different pedal frequencies. Eleven collegiate athletes (5 cross-country runners, END; 6 sprinters, SPR), ages 18-23, performed exhaustive rides at either 60- or 100-rpm on separate days for the determination of the pedal rate-specific CP. The CP-V.O2 was determined from an 8-minute ride at the CP for each pedal frequency. The group mean CP was significantly lower at 100-rpm (189 ± 50 W) compared to 60-rpm (207 ± 53 W, P < 0.05). However, the group mean CP-V.O2 at 60- (2.53 ± 0.60 L*min-1) and 100- (2.58 ± 0.53 L*min-1) rpm were not significantly different. CP was significantly higher in the END athletes (60-rpm = 242 ± 50 W; 100-rpm = 221 ± 56 W) compared to SPR athletes (60-rpm = 177 ± 38 W; 100-rpm = 162 ± 27 W, P < 0.05) at both pedal frequencies, but CP-V.O2 was not (P > 0.05). However, when the CP-V.O2 was scaled to body weight, the END athletes had a significantly greater CP-V.O2 (60-rpm = 41.3 ± 4.1 ml*min-1*kg-1; 100-rpm = 40.8 ± 5.5 ml*min-1*kg-1) compared to the SPR athletes (60-rpm = 27.7 ± 4.6 ml*min-1*kg-1; 100-rpm = 29.4 ± 2.8 ml*min-1*kg-1, P < 0.05) at both pedal frequencies. We conclude that CP represents a specific metabolic rate (V.O2) which can be achieved at different combinations of power outputs and pedaling frequencies.
Key Words:
Exercise, Muscle fatigue, VO2
