by Joel Jamieson
Aerobic power is the maximum rate of power than can be produced through aerobic metabolism. This is most commonly measured by looking at the power output or speed at VO2 max – though it will certainly correlate highly to power output at lactate threshold as well.
The amount of power an athlete can generate aerobically is essentially a direct measure of the maximum amount of power they can maintain for long duration and also important even in fairly short duration activities if they are repetitive.
Anaerobic power is a measure of how much power the anaerobic energy systems are capable of generating. Although this level of power output is invariably much greater than the amount generated by aerobic metabolism, it can only be maintained for relatively short periods of time before fatigue sets in and power output is drastically reduced.
Science is still unclear as to all the exact mechanisms that lead to the rapid fatigue associated with a heavy reliance on anaerobic metabolism, but it’s likely the result of many different peripheral factors that reduce muscle contractility as well central factors that decrease neural drive to the working muscles.
Anaerobic Power Reserve
The Anaerobic Power Reserve is a measure of the difference between the maximum amount of power that can be generated anaerobically compare to aerobically. The greater the difference between the two, the greater the anaerobic power reserve.
The anaerobic power reserve can be used to predict the rate of fatigue both in cycle and acyclic activities. In other words, the greater the level of anaerobic power reserve and the more you rely on anaerobic metabolism, the faster you will fatigue.
This is true both in a sport where power output is constant, such as in a sprint and in repetitive sports like football, soccer, basketball, etc. This simple principle is hugely important to understanding conditioning and fatigue because it explains how energy system contribution direction relates to fatigue and performance.
Weyand, P. G., Lin, J. E., & Bundle, M. W. (2006). Sprint performance-duration relationships are set by the fractional duration of external force application. American journal of physiology. Regulatory, integrative and comparative physiology, 290(3), R758–65. doi:10.1152/ajpregu.00562.2005
Mendez-Villanueva, A., Hamer, P., & Bishop, D. (2008). Fatigue in repeated-sprint exercise is related to muscle power factors and reduced neuromuscular activity. European journal of applied physiology, 103(4), 411–9. doi:10.1007/s00421-008-0723-9