Abstract
Our purpose was to determine if using an individual’s power-specific gross efficiency
improves the accuracy of estimating energy expenditure from cycling power. 30 subjects
performed a graded cycling test to develop 4 gross efficiencies: individual power-specific
gross efficiencies, a group mean power-specific gross efficiency, individual fixed
gross efficiencies, and a group mean fixed gross efficiency. Energy expenditure was
estimated from power using these different gross efficiencies and compared to measured
energy expenditure during moderate- and hard-intensity constant-power and 2 variable-power
cycling bouts. Estimated energy expenditures using individual or group mean power-specific
gross efficiencies were not different from measured energy expenditure across all
cycling bouts (p>0.05). To examine the intra-individual variability of the estimates,
absolute difference scores (absolute value of estimated minus measured energy expenditure)
were compared, where values closer to zero represent more accurate individual estimates.
The absolute difference score using individual power-specific gross efficiencies was
significantly lower compared to the other gross efficiencies across all cycling bouts
(p<0.01). Significant and strong correlations (r≥0.97, p<0.001) were found across
all cycling bouts between estimated and measured energy expenditures using individual
power-specific gross efficiencies. In conclusion, using an individual’s power-specific
gross efficiency significantly improves their energy expenditure estimate across different
power outputs.
Key words
cycling economy - oxygen uptake - power meters