AeroLab Tech

Freeride analysis is now live in a beta distribution! This tool is to help coaches, fitters, and athletes understand how CdA can vary when training and in race like efforts! It also offers an excuse to get out on days like these! 😉

How important is aerodynamic adaptation?

Above is a graph following the story of an athlete improving their aerodynamics and adapting over time. The blue curve shows the power to overcome aerodynamic drag while the yellow curve show steady state speed accounting for all losses. This athlete was able to increase their TT speed with no change in FTP (270W) or hours on the bike.

A recently tested athlete told us the story of how they got aero over the past two years. The first improvement was clip-on aerobars with their road bike (point A, CdA 0.295). Being well back of the leaders they were motivated to purchase a TT bike and adopted the “slam the stem” mantra. Needless to say, in their next race they blew up attempting to hold target power 270 Watts in a new “aero” position (point B, CdA 0.277). Their race performance hadn’t improved by simply purchasing a new TT bike.

Stumped, our athlete decided to visit a aero-certified bike fitter. Following an in-studio bike fit and trying on a TT helmet the athlete tested on the road at a CdA of 0.251 (point C). Optimizing helmet choice over a series of tests the athlete was able to drop further to a CdA of 0.244 (point D). The fitter explained to the athlete that achieving this position would result in a decrease in sustainable power without adaptation, notice the drop of about 15 Watts.

Consistent training over a 4 month period in this new position the athlete was able to bring up their target power from 255 back to 270. In addition, trying a aero-road helmet which better conditioned the air flow over the rider, the athlete was able to further decrease their CdA to 0.233 (point F). This reduction in CdA from point D to F is not solely due to the change in helmet. Due to the adaptation over the 4 month period the athlete was able to comfortably maintain position. The only change to the athletes daily routine was more training in aero.

From the CdA values we predicted the athletes 40km TT performance on a flat smooth course for positions A and F from 61 min and 22 sec to 56 min and 39 sec, a decrease 7.74%.