· Title: Apparatus to measure the angular positioning of the cleat of clipless pedals

· Status: In progress

· Background: Passionate cyclists use clipless pedals because they allow efficient power transmission to the bicycle. A cleat fixed to the shoe connects the pedal to the shoe. Several model of cleats can provides a degree of freedom of the shoe (floating angle) around an axis perpendicular to the pedal surface. This floating allows a natural orientation of the feet while pedaling. A serious cyclist riding 5000 km a year will gives typically one million pedal strokes. In order to avoid overuse injury linked with the repetitive nature of pedaling, it is important that the cleat be positioned (oriented) correctly during its installation on the shoe. This orientation can depend on the pedaling technique, the cyclist morphology, etc. Before this project, there was no method or measurement technique that allowed in real condition of operation (that is on the road), the adequate measuring of the floating angle use by the cyclist.

· Main Objective: Develop a measurement technique and an instrument to measure the floating angle of a clipless pedal in real condition of operation (on the road).

· Description: A small magneto-resistive sensor is integrated in a commercial clipless pedal (LOOK KéO). The transducer has a very high resolution (0.07º) and is based on the measurement of the magnetic field orientation. Contrary to an encoder, this system does not require any absolute positioning. The transducer is connected to a WheatStone bridge. A data acquisition system (ISAAC model V7) allows to measure simultaneously the right and left pedal floating angle as well as a one per rev signal. At a sampling frequency of 1 kHz and with a memory card of 128 Mo, more than 5 h or recording is available. A small magnet is temporarily fixed to the cleat. Any movement of the shoe (and the cleat) changes the magnetic field orientation and is picked by the sensor. This instrument is not invasive and do not alter the natural pedaling pattern. It is then easy to measure if the floating angle range is adequately used by the cyclist. The modification of the orientation on the shoe is easily done with the help of a template. A cyclist that would prefer to use a cleat that offers not floating would probably be wise to first orient adequately its cleat with this system. This invention is patent pending. A research project studying the influence of the floating on the muscular activation is in progress.

· Partners: LOOK Cycle International.