Glossary: Aerobic Efficiency (AE)
Aerobic Efficiency measures the ratio of intensity to effort, using pace or power as intensity and heart rate as effort. With an increase in performance, higher efficiency values are expected over the long term, since a higher power/pace is achieved at the same heart rate.
Since intensity is measured in terms of pace or power, which can vary greatly from one sport to another, the efficiency values are not comparable across different sports.
Even within one sport, efficiency values by pace and by power cannot be compared, even if we use a constant scaling factor to keep the values in similar ranges.
AE (Pace) = 47 * Speed [m/s] / Heart rate [bpm]
AE (Power) = Power [W] / Heart rate [bpm]