Optimal power-to-mass ratios when predicting flat and hill-climbing time-trial cycling

Nevill, A. M.; Jobson, S. A.; Davison, R. C. R.; Jeukendrup, A. E.

Abstract

The purpose of this article was to establish whether previously reported oxygen-to-mass ratios, used to predict flat and hill-climbing cycling performance, extend to similar power-to-mass ratios incorporating other, often quick and convenient measures of power output recorded in the laboratory [maximum aerobic power (W MAP), power output at ventilatory threshold (W VT) and average power output (W AVG) maintained during a 1 h performance test]. A proportional allometric model was used to predict the optimal power-to-mass ratios associated with cycling speeds during flat and hill-climbing cycling. The optimal models predicting flat time-trial cycling speeds were found to be (W MAP m −0.48)0.54, (W VT m −0.48)0.46 and (W AVG m −0.34)0.58 that explained 69.3, 59.1 and 96.3% of the variance in cycling speeds, respectively. Cross-validation results suggest that, in conjunction with body mass, W MAP can provide an accurate and independent prediction of time-trial cycling, explaining 94.6% of the variance in cycling speeds with the standard deviation about the regression line, s=0.686 km h−1. Based on these models, there is evidence to support that previously reported -to-mass ratios associated with flat cycling speed extend to other laboratory-recorded measures of power output (i.e. Wm −0.32). However, the power-function exponents (0.54, 0.46 and 0.58) would appear to conflict with the assumption that the cyclists’ speeds should be proportional to the cube root (0.33) of power demand/expended, a finding that could be explained by other confounding variables such as bicycle geometry, tractional resistance and/or the presence of a tailwind. The models predicting 6 and 12% hill-climbing cycling speeds were found to be proportional to (W MAP m −0.91)0.66, revealing a mass exponent, 0.91, that also supports previous research.

Citation

Nevill, A. M., Jobson, S. A., Davison, R. C. R., & Jeukendrup, A. E. (2006). Optimal power-to-mass ratios when predicting flat and hill-climbing time-trial cycling. European Journal of Applied Physiology, 97(4), 424-431. https://doi.org/10.1007/s00421-006-0189-6

• Journal Article Type: Article
• Acceptance Date: Mar 17, 2006
• Online Publication Date: May 10, 2006
• Publication Date: 2006-07
• Deposit Date: Jun 13, 2008
• Journal: European Journal of Applied Physiology
• Print ISSN: 1439-6319
• Electronic ISSN: 1439-6327
• Publisher: Springer
• Peer Reviewed: Peer Reviewed
• Volume: 97
• Issue: 4
• Pages: 424-431
• DOI: https://doi.org/10.1007/s00421-006-0189-6
• Keywords: Power supply and demand; Cycling speed; Maximal aerobic power, Power at ventilatory threshold, Average power output
• Public URL: http://researchrepository.napier.ac.uk/id/eprint/1634