Most mountain bike cyclists have preferred dual suspension to front suspension, but the advantage of dual suspension has not been fully ascertained scientifically. Two suspension systems, dual and front suspension, are compared on shock absorption and leg muscle activity during downstairs ride. Eight experienced male mountain bike racers descended stairs on mountain bikes with front suspension (FS) and dual suspension (DS) formats. Peak acceleration and muscle activity in the leg were determined using accelerometers placed on the lumbar regions of the cyclists and immediately adjacent to the rear wheel axle bracket for the duration of the trial. Simultaneously, the activities of twelve major leg muscles were monitored using surface electromyography for bilateral leg activity of m. rectus femoris, m. biceps femoris, m. gluteus maximus, m. vastus lateralis, m. tibialis anterior and m. gastrocnemius. In the results, no significant differences were observed in peak acceleration between FS and DS at the rear wheel axle. However, peak acceleration using DS was significantly less than that observed with FS in the lumbar region of cyclists. Muscle activities for m. rectus femoris and m. biceps femoris on the back side of the leg were significantly lower using DS compared to FS. These results lead to the conclusion that DS systems absorb terrain-induced shock more effectively than FS systems, as well as reducing muscle activity in most leg muscles during downhill cycling. Cyclists could therefore achieve higher cycling performance using DS systems.