Bike shock absorption systems reduce the energy variation induced by terrain irregularities,
leading to a greater comfort. However, they may also induce an increase in energy
expenditure for the rider. More specifically, cross-country racers claim that rear
shock absorption systems generate significant energy loss. The energy losses caused
by such systems may be divided in terrain-induced or rider-induced. This study aims
at evaluating the rider-induced energy loss of modern suspended bicycles riding on
a flat surface. Twelve experienced competitive racers underwent three multistage gradational
tests (50 to 250 W) on a cross-country bicycle mounted on an electromagnetically braked
cycle ergometer. Three different tests were performed on a fully suspended bike, front
suspended and non-suspended bicycle, respectively. The suspension mode has no significant
effect on V˙O2. The relative difference of V˙O2 between the front-suspended or full-suspended bike and the rigid bike reaches a non
significant maximum of only 3 %. The claims of many competitors who still prefer front
shock absorption systems could be related to a possible significant energy loss that
could be present at powers superior to 250 W or when they stand on the pedals. It
could also be generated by terrain-induced energy loss.
Bicycle-shock-absorption-systems, mountain-bike-cross-country, energy-consumption.
