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Excerpt
Modeling algorithms of the one hour (1 h) cycling record typically incorporate decreases to both aerodynamic drag (RD) and maximal oxygen uptake (˙VO2MAX) with increases in altitude. Previous modeling studies (di Prampero et al., JAP, 1979; Capelli & di Prampero, EJAP, 1995), however, have never addressed whether differences in body mass (MB) would influence their conclusions. Anecdotally, larger cyclists are considered to have an advantage over smaller cyclists in any flat time-trial, while altitude performances are generally faster than sea-level performances. The present study simulated how differences in MB (60-100 kg) could influence the 1 h cycling record at both sea-level and altitude (0-7 km) using an iterative modeling algorithm generated in QuickBASIC™. Assuming RD as the only force resisting forward motion (power demand), the energy required to overcome RD was modeled to scale with MB to the ⅓ power (ie. VO2 ∝ RD ∝ MB0.33; Swain, MSSE 1994). The ability of cyclists to generate external power to overcome RD was modeled as proportional to ˙VO2MAX, while ˙VO2MAX was modeled to scale with MB to the ⅔ power(Heil, RQES A-22, 1997). Equations from the literature were used to account for decreases in both RD and ˙VO2MAX with an increase in altitude from sea-level. The simulation results generally supported both anecdotal and previous modeling observations. Specific findings include: 1) An optimal altitude for the 1 h cycling record was 4-4.5 km regardless of MB (higher than previously predicted); 2) Larger cyclists had the same performance advantage over smaller cyclists at all altitudes; and 3) simulated 1 h cycling distance scaled with MB to the +0.168 power at all altitudes. Given that the current 1 h cycling record of 56.375 km was established at sea-level by a 67 kg cyclist using a currently illegal aerodynamic position (Chris Boardman, 1996), the present results indicate that even greater distances of 56.7-58.4 kms could be achieved by larger cyclists(75-90 kg) of similar fitness at a 4 km altitude track.
