RChung

Been there, done that. It used to be common for pro riders to post their power data both from races and from training but it's less so today. Fortunately, I have some data files from some pro riders in a few races, including the TdF. This isn't a TdF file, it's from the 2009 Tour of California, but it's pretty typical of a "hilly" race.



In the context of pedal force and pedal speed, the plot below shows the "typical" range of pedal force (in lbf), cadence, and power for a 160 lb rider. If riders were cruising along at 170 watts they could be doing so at any point along the 170 watt curve. Some riders will choose slightly lower cadence and commensurately slightly higher pedal force, others will choose the other way 'round. If, starting from 170 watts they decided to increase to 400 watts, they could likewise choose any point along the 400 watt curve, and that would identify a different combination of cadence and pedal force. It's good for riders to be able to generate power at many different combinations because the demands of riding vary. Only if conditions are constant will riders tend to use a constant combo of cadence and pedal force. ln practice, the slope changes, the wind blows, you get tired, so the conditions aren't constant. But, importantly, when we look at the data, we see that although riders often *think* they ride at a fixed cadence, they don't. *If* riders rode at a fixed cadence, then moving from the 170 watt curve up to the 400 watt curve would always look like a vertical movement. What happens is that they take all different paths (sometimes diagonally right, sometimes horizontally right, sometimes diagonally left -- and sometimes they do move vertically). These "power expansion paths" vary with the rider, and they vary with the conditions the rider is facing.