Cycling efficiency in trained male and female competitive cyclists

The aim of this study was to examine differences in cycling efficiency between competitive male and female cyclists. Thirteen trained male (mean + SD: 34 ± 8 yr, 74.1 ± 6.0 kg, Maximum Aerobic Power (MAP) 414 ± 40 W, VO_2max 61.3 ± 5.4 ml kg^-1 min^-1) and 13 trained female (34 ± 9 yr, 60.1 ± 5.2 kg, MAP 293 ± 22 W, VO_2max 48.9 ± 6.1 ml kg^-1 min^-1) competitive cyclists completed a cycling test to ascertain their gross efficiency (GE). Leg and lean leg volume of all cyclists was also measured. Calculated GE was significantly higher in female cyclists at 150W (22.5 ± 2.1 vs 19.9 ± 1.8%; p < 0.01) and 180W (22.3 ± 1.8 vs 20.4 ± 1.5%; p = 0.01). Cadence was not significantly different between the groups (88 ± 6 vs 91 ± 5 rev·min^-1). Lean leg volume was significantly lower for female cyclists (4.04 ± 0.5 vs 5.51 ± 0.8 dm³; p < 0.01) and was inversely related to GE in both groups at 150 and 180W (r = -0.59 and -0.58; p < 0.05). Lean leg volume was shown to account for the differences in GE between the males and females. During an "unloaded" pedalling condition, male cyclists had a significantly higher O₂ cost than female cyclists (1.0 ± 0.1 vs 0.7 ± 0.1 L·min^-1; p < 0.01), indicative of a greater non-propulsive cost of cycling. These results suggest that differences in efficiency between trained male and female cyclists can be partly accounted for by sex-specific variation in lean leg volume.