D12 Efficiency

Topic

This efficiency assessment generally quantifies the relationship between the useful mechanical energy produced by the athlete and the metabolic energy consumed to generate it—specifically, the mechanical energy of the center of mass as defined by the model in question.

This efficiency is calculated as "gross efficiency" when the athlete's basal metabolic rate is included in the denominator of the ratio, or as "net efficiency" when that basal metabolic rate is excluded from the denominator. Excluding the basal metabolic rate from the denominator results in a net efficiency value that is higher than the corresponding gross efficiency.

The athlete's "cost of transport" normalizes energy expenditure based on both the distance covered and body mass; consequently, it is the most widely used metric for comparing movement economy between different individuals or sports disciplines.

The athlete's oxygen consumption is measured via indirect calorimetry using ergospirometry equipment; both oxygen consumption and carbon dioxide production are converted into energy expenditure using the oxygen energy equivalent—a value that varies according to the athlete's respiratory exchange ratio at any given moment. Thus, running economy is defined as the oxygen consumption measured while the athlete maintains a constant submaximal speed. Consequently, this model—based on the relationship between useful mechanical energy and consumed metabolic energy—reveals that the final efficiency is extraordinarily high during cycling, thanks to the machine's minimal mechanical loss, yet considerably lower during swimming, precisely due to the additional hydrodynamic resistance the athlete must overcome in the water. Based on oxygen consumption, carbon dioxide production, the athlete's speed, ground reaction force, and the kinematics established by the other models in this set, this analysis determines the cost of transport, running economy, and the final efficiency with which the model began.

ID:1214