Effect of air resistance on the metabolic cost and performance of cycling

SummaryThe metabolic cost (VO2) of cycling against a range of wind velocities (VW) was studied in a wind tunnel of 15 male cyclists and the results compared with work on a stationary cycle ergometer, uphill cycling on a treadmill, and performance times in road racing competitions.The results showed that VO2 at constant treadmill speed was proportional to VW2and was a linear function of work rate, both on the stationary ergometer and during uphill cycling on a motor driven treadmill. Maximal values of 5.04 1×min−1 (69.3 ml×kg−1×min−1) and 482 W were observed. The mean force (F) acting on the cyclists during the experiments in the wind tunnel was found to be equal to 0.0175 VW2×ms−1 (r=+0.98). The mean projected area (AP), drag areas (AD) and drag coefficient (CD) for the 15 cyclists were 0.50 m2, 0.280 m2, and 0.56 m2, respectively. During cycling out of doors on a calm day VO2 was calculated to be a curvilinear function of the cyclists' speed of progression (V). The best guide to the cyclists' maximal aerobic power output (VO2 max) was given by their 16.1 km (10 mile) time: $$\dot VO_{2\max } (1 \times \min ^{ - 1} ) = - 4.219 + 0.7727{\text{ }}V(ms^{ - 1} )r = + 0.89.$$ The results suggested that the relative aerobic power output (% VO2 max) which could be sustained for a given time by elite cyclists, is similar to that found previously for marathon athletes. However, due to the differences in the non-drag component of the work for given metabolic cost the cyclist will travel approx. 2 1/2 times the distance of an endurance athlete.