In wheelchair racing, measuring pushrim kinetics such as propulsion forces and moments is paramount for improving performance and preventing injuries. However, there is currently no instrumented racing wheel that records 3D pushrim kinetics wirelessly and at a high sample rate, which is necessary for accurately analyzing wheelchair racing biomechanics. In this work, we present an instrumented wheel that measures 3D kinetics at 2500 Hz. Bidirectional wireless communication is used to interface the wheel through a smart phone. The wheel was tested with a world-class racing athlete who propelled at maximal acceleration and maximal speed on a training roller. During acceleration, the peak total force increased continuously from 186 N to 484 N while the peak tangential force was constant at 171 N ± 15 N. At higher speeds, a counterproductive tangential force was measured during the first 15% and the last 25% of the push phase, peaking at -78 N. This wheel may be of great value for both coaches and athletes to help with planning and validating training programs and adaptations to the wheelchair such as positioning. This wheel also has very high potential for further research on wheelchair racing biomechanics and on preventing shoulder pathologies associated with this sport.
Improving ride quality is a paramount concern for road cyclists who are subjected to road induced vibrations during long rides. It has been hypothesized that adding structural damping to the bicycle can decrease the vibration levels transmitted to the cyclist. The human body is most sensitive to vibrations in the frequency range of 0-60 Hz, and the amount of damping added by the cyclist when riding the bicycle is very large. This could potentially reduce the net benefit of small improvements provided by structural damping. This paper reveals the effects of structural damping modifications on the modal parameters of a bicycle frame and on the amount of vibrations transmitted to the cyclist due to road surface excitation. A bicycle frame originally designed with damping gel inserts was tested in three different configurations: (1) with its damping gel inserts, (2) with its damping gel inserts and additional damping material wrapped around the frame's tubing and (3) without its damping gel inserts. Three different metrics were used to assess the damping material effect on vibrations transmitted to the cyclist at the hands and buttocks: acceleration, transmitted force and power absorbed by the cyclist. This paper shows that in all configurations and measurements, added damping did not reduce the vibrations transmitted to the cyclist.
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