Date of Award

Spring 1-1-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

First Advisor

Rodger Kram

Second Advisor

Thomas LaRocca

Third Advisor

Alena Grabowski

Abstract

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 rode 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.

Included in

Biomechanics Commons

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