The purpose of power maximization is to position a cyclist on his bicycle in
such a manner that the percentage of effective power yielded by the cyclist is
as large as possible. Only the power which is exercised vertically on the pedal
arm (see figure 1) is effective. When the pedal is positioned at the lowest or
upper 'dead' point, the effective power that results is practically negligible
(figure 2). This means that especially when the crank is in the 90 degrees
position (maximum leverage), the adjustment of the bicycle must be such that
the power that is exercised, is exactly under a 90 degrees angle on the crank.
This also means that the forward and backward adjustment of the saddle plays an
important role. If the saddle is placed too much in a backward position, it
will result in a pedal position that corresponds with position 2 of figure 1.
If, on the contrary, the saddle is placed too much in a forward position, the
pedal will correspond with position 3 of figure 1. The blue arrow represents
the power that is exercised, green represents effective power, and red
represents loss of power.
It goes without saying that the most efficient position and the position that
leads to the most effective exercise of power does not necessarily have to
coincide. Where exactly to find the optimum between the two is still a matter
of research and debate. This optimum is likely to vary, depending on the
cycling event and the type of cyclist. For cycling competitions lasting more
than one day, the emphasis tends to be on an efficient position on the bicycle,
whereas in time trials the aspect of power is given a higher priority. Cyclists
with a relative "slow-twitch" physiology of the muscles will choose for power,
while cyclists with a "fast-twitch" muscle physiology are more likely to opt
for suppleness and flexibility.
Yet, it is justified to draw some conclusions based on empirical evidence.
Generally, it can be asserted that in case of an increase in saddle height, the
extent to which power can be exercised will increase; however, this will lead
to a loss of speed of the cycling movement (cadence)
which, in turn, determines the level of efficiency of the cyclist. In other
words, a high position of the saddle is only recommended in short-term efforts
that require a lot of power such as off-road cycling, mountain biking and
uphill time-trials. A high position of the saddle very often leads to use of
heavier gears which, in the long run, could lead to complaints and injuries.
The same can be said about crank length. Longer cranks lead to more power, but
they decrease the number of pedal rotations per minute. For the moment the
aspect of power maximization will remain a matter of trial and error, with
biomechanical elements as well as elements of injury prevention and physical
straining.
Research into power maximization in the cycling sport has led to the development
of the ellipse-shaped chain-wheel. The purpose of this ellipse-shaped
chain-wheel is to increase the angle speed of the crank when it is in the
lowest or upper 'dead' point at a constant chain speed. The moments in the
pedaling cycle that yield little effective power will thus be made shorter;
however, research has never been able to prove the effectiveness of these
chain-wheels and, as a consequence, they are no longer used in competitive
cycling. It is assumed that the element of muscle coordination is decisive;
trained cyclists only want to exercise a steady and regular pedaling movement.

Figure 1
The power that is exercised exactly under a 90 degrees angle on the crank is
effective.
Figure 2
The red line represents the effective pedal load during 1 rotation, starting at
the top dead point.
In the last few years the cycling
sport has evolved from an endurance sport to a power endurance sport. In the
1940s and 50s it was common to use gear ratios of 49 x 17. At present, gears of
53 x 11 or even larger are no longer exceptions. In order to use these gears
over a longer period of time, it is essential that the power that is supplied
is used as efficiently as possible.