Visualization of Pedaling Technique Using Cleat-size Biaxial Load Cells

A visualization system for cycling pedaling technique is investigated in this paper. This system consists of the visualization of pedaling effectiveness and pedaling force vectors. Pedaling effectiveness is defined as the ratio of the tangential to total force applied to the pedals. New biaxial load cells were also developed to attach to the bottom of cycling shoes in place of plastic cleats. These load cells can be connected to the bicycle pedals to measure the magnitude and direction of pedaling forces of both pedals, respectively. The size of load cells is comparable with detachable plastic cleats (Shimano Corp). Therefore, cyclists were permitted to use their own bicycles for performance tests. For visualization of pedaling effectiveness, each force measured by the load cell was converted to coordinates respective to the tangential and radial directions of each crank. The crank angle was calculated from the signal of a magnetic transducer. The pedal angle was calculated using a link mechanism with the lower limbs: the length of the lower limbs, the length of the crank and the position of the greater trochanter were used as constant parameters for computational calculations. For visualization, the relationship between crank angle and force vectors was plotted on a computer, just after the performance tests. This information would be provided for coaches and cyclists in order to identify improvement points for pedaling technique.