Bicycle suspension elements smooth the vibrations generated by irregularities in the road or trail surface. However, it is unknown whether the energy put into the suspension system exacts a metabolic or mechanical cost. Here, I investigated the effects of suspension systems on the energetics and mechanics of riding bicycles on smooth uphill surfaces in both the sitting and standing positions.

Chapter 1:​ Twelve male cyclists road at 3.35m/s up a motorized treadmill inclined to 7% grade. All subjects used the same road bike equipped with a steering tube front suspension system. Each subject completed six 5 minute trials separated by 5-minute rest periods, with the suspension system in rigid (locked) and compliant settings. I measured their metabolic rates from oxygen consumption and carbon dioxide production. I also measured their mechanical power outputs. In the sitting position, metabolic power averaged 13.10±0.54 (rigid) and 13.21±0.54 W/kg (compliant). Mechanical power averaged 2.83±0.06 W/kg in both conditions. During standing, metabolic power averaged 14.22±0.73 (rigid) and 14.17±0.81 W/kg (compliant). Mechanical power averaged 2.86±0.03 and 2.87±0.05 W/kg respectively. None of these differences were statistically significant.

Chapter 2:​ Eight male and four female mountain bikers rode at 2.77m/s up a motorized treadmill inclined to 7% grade. Subjects rode a dual-suspension mountain bike. Each subject completed six 5 minute trials separated by 5-minute rest periods, with the suspension set to firm and soft conditions. I measured their metabolic rates from oxygen consumption and carbon dioxide production. I also measured their mechanical power outputs. In the sitting position, metabolic power averaged 11.38±0.48 (firm) and 11.44±0.49 W/kg (soft). Mechanical power averaged 2.54±0.20 W/kg in both conditions. During standing, metabolic power averaged 12.46±0.62 (firm) and 12.63±0.90 W/kg (soft). Mechanical power averaged 2.57±0.21W/kg in both conditions. None of these differences were statistically significant.

In conclusion, suspension systems in both road and mountain bikes had no effect (p>0.10) on the metabolic or mechanical power required for bicycle riding on smooth uphill surfaces in either seated or standing positions.