The study evaluates exactly two variables: the absolute difference in pedal pressure and the pressure distribution between both feet. This restriction is methodologically justified.
Definition of force
The study defines force as the product of mass and acceleration. The unit is the newton: 1 N = 1 kg · m/s². A force thus describes an action on a body that accelerates or decelerates it.
In cycling this force acts directly on pedal and crank and thereby indirectly generates propulsion.
Why not measure speed?
The resulting propulsion additionally depends on factors unrelated to the insole — such as gear ratio and tyre size. An evaluation via final speed would have measured these confounders as well. To ensure an objective evaluation, the study therefore restricts itself to pedal pressure and pressure distribution.
Measurement location: in the shoe, not at the pedal
Pressure was measured directly inside the cycling shoe. This reveals not only the sum of the transmitted force but also through which areas of the sole that force is introduced. It is precisely this spatial resolution that makes the stabilisation of force distribution visible.
Evaluated variables
- Absolute difference in pedal pressure with and without the additional insole (Figure 1).
- Deviation from the optimal 50/50 distribution of pressure moments between right and left foot (Figure 2).
- Spatial pressure distribution across the sole of the foot as a pressure image (Figure 3).