The pedaling frequency is the number of rotations of the pedal per minute. Research into the optimal pedaling frequency has been extensive. Already in 1929, Hartree and Hill indicated that there had to be an optimal pedaling frequency. When a cyclist pedals too slowly, energy is taken away from both power, as well as duration of contraction. On the other hand, if a cyclist pedals too quickly, energy is lost to overcoming internal resistance in the muscle. So there has to be an optimum; however, Hartree and Hill failed to indicate where this optimum was to be found.
In other surveys, the lowest level of oxygen intake was used as a criterion. Gregor (1986) presented an overview of these studies. In most instances, the result was somewhere between 33 and 80 rotations per minute (rpm); however, in reality, most cyclists invariably choose a frequency that lies between 90 and 110 rpm. At first it was believed that this difference could be explained by the effect of training, but this hypothesis lost ground as a result of tests conducted by Boning and associates (1986). He tested both trained as well as untrained test persons and came to the conclusion that, in spite of the greater effort that untrained test persons experienced when resistance increased, the optimal pedaling frequencies did not change. A few years earlier, however, Hagberg (1981) made an interesting discovery. He noticed that, when deducting oxygen usage in cycling without resistance from the oxygen usage in cycling with resistance, the optimal pedaling frequency shifted towards 100 rpm. Redfield and Hull (1986) had an explanation. They used the sum of the torques in ankle, knee and hip as a criterion (Cost function, see diagram). This was calculated in the function of the pedaling frequency, and it appeared that it was the lowest between 90 and 100 rpm. This corresponds quite well with the pedaling frequency of cyclists in everyday reality.

Cost function

Crank arm
length

Optimal combination
of cadence and
crank arm length

Minimum cost

Cadence

High-Tech Cycling (1996)

In other research, Hull (1988) looked into pedaling frequency in more depth. He made use of a combination of joint torques and tension in the muscles in relation to the pedaling frequency. In this survey an optimum was also found at a frequency between 90 and 100 rpm. Apparently, the tension that arises in the leg muscles during cycling is the most decisive factor for the pedaling frequency. This shows that already in 1929 Hartree and Hill came very close to explaining why lower pedaling frequencies were far from ideal.