The power variation needed to completely eliminate speed fluctuations would be physiologically impossible. The greater the variation in power that the cyclist can handle, the greater the advantage in performance time. As noted at the beginning of this section, the freewheel descent allows almost complete rest. It should also be noted that the computer simulation demonstrated that the variable power strategy is also effective in countering the effects of varying wind conditions. The primary forces a cyclist must overcome are air resistance and gravity.
Air resistance increases exponentially with speed.
In the transition from cycling on a flat road to climbing a hill, the decreased speed reduces air resistance to the point where drafting other riders provides little benefit. At this point, riders with superior aerobic power to weight ratios will be able to breakaway from the peloton. Due to scaling considerations, this favors smaller riders. Climbing ability can be enhanced by minimizing weight, and also by pedaling at a consistently high cadence. Large cyclists can achieve greater downhill speeds, but overall performance still favors smaller cyclists on hilly courses.