Article

Comparing cycling world hour records, 1967-1996: Modeling with empirical data

University of Colorado Colorado Springs, Colorado Springs, Colorado, United States
Medicine &amp Science in Sports &amp Exercise (Impact Factor: 4.46). 12/1999; 31(11):1665-76. DOI: 10.1097/00005768-199911000-00025
Source: PubMed

ABSTRACT The world hour record in cycling has increased dramatically in recent years. The present study was designed to compare the performances of former/current record holders, after adjusting for differences in aerodynamic equipment and altitude. Additionally, we sought to determine the ideal elevation for future hour record attempts.
The first step was constructing a mathematical model to predict power requirements of track cycling. The model was based on empirical data from wind-tunnel tests, the relationship of body size to frontal surface area, and field power measurements using a crank dynamometer (SRM). The model agreed reasonably well with actual measurements of power output on elite cyclists. Subsequently, the effects of altitude on maximal aerobic power were estimated from published research studies of elite athletes. This information was combined with the power requirement equation to predict what each cyclist's power output would have been at sea level. This allowed us to estimate the distance that each rider could have covered using state-of-the-art equipment at sea level. According to these calculations, when racing under equivalent conditions, Rominger would be first, Boardman second, Merckx third, and Indurain fourth. In addition, about 60% of the increase in hour record distances since Bracke's record (1967) have come from advances in technology and 40% from physiological improvements.
To break the current world hour record, field measurements and the model indicate that a cyclist would have to deliver over 440 W for 1 h at sea level, or correspondingly less at altitude. The optimal elevation for future hour record attempts is predicted to be about 2500 m for acclimatized riders and 2000 m for unacclimatized riders.

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    • "This has resulted in a dramatic increase in the speeds reached from the 1974, 200m speed record of 69.23km/h to the present record which stands at 133.284km/h. Chester Kyle performed some of the most notable research on the aerodynamic design for cycling during some 4 decades [3] [4] [5] [6]. Most record breaking human powered vehicle concepts have focused on the aerodynamic design as air resistance is the most predominant factor that has to be overcome [2]. "
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    • "Therefore, OCw could increase substantially after 3,000 m due to the combined effects of environmental conditions and fatigue. In addition, _ VO 2max decreases in relation to altitude, dropping to approximately 70% of the sea level _ VO 2max at 5,000 m (Bassett et al. 1999; Péronnet et al. 1989; Mazzeo 2008). An increase in OCw may also decrease _ VO 2 reserve, causing a higher fractional use of _ VO 2max , especially in the final ascent phase. "
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    • "). Nonetheless, Bassett et al. (1999) estimate that cyclists' drag coefficient is typically constant when wind speed ranges between 50 and 60 km Á h 71 . Before the tests, the force balance was zeroed at a wind speed of 15 m Á s 71 , to exclude the aerodynamic drag of the power meter. "
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