Redefining Road Cycling Performance From Field Determinations of Power Output

In the laboratory, cycling has been a common model for studying the physiological responses to physical activity due to its popularity as a recreational activity, the ability to precisely quantify the exercise stimulus through measures of power and work, and the diverse physiological demands imposed by competitive cycling events. To date, this research effort has been limited primarily to steady state or graded exercise protocols in controlled laboratory environments. Recent technological advances, however, have resulted in the development of hub and crank based power meters that can be fitted to standard road bicycles, allowing power and work to be monitored in the field. Thus, in the same way that cycling has been an important model for laboratory research, the intent of this present research has been to extend this model to the field with an initial emphasis on redefining road cycling performance. As a first step we demonstrated that cycle mounted power meters were accurate and precise under dynamic load against both physiological and mechanical references. We then focused on examining the demands of competitive cycling in female and male professional cyclists, observing a complex, seemingly stochastic pattern of power output during competition that encompassed a much broader power and metabolic spectrum than previously characterized by laboratory simulations or field measures of heart rate. Because this pattern of power output is a result of a cyclist’s physiological capacity to produce power and physical factors that impede forward motion, we validated a protocol for isolating aerodynamic drag and rolling resistance from field measures of power and speed, showing that these variables could be measured to a degree of accuracy comparable to more costly, complicated, and less specific methods. Finally, using this technique in combination with physiological measures gathered in the laboratory, we were able to dissect the physical and physiological attributes determining uphill and level time trial performance in the field