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Measuring changes in aerodynamic/rolling resistances by cycle-mounted power meters
Allen C Lim1, Eric P Homestead, Andrew G Edwards
1Department of Integrative Physiology, University of Colorado, Boulder, CO, USA.
Medicine and Science in Sports and Exercise
|October 1, 2010
Summary
This study shows that bicycle power meters can detect changes in aerodynamic and rolling resistance from body position and tire pressure. These findings help cyclists optimize performance by understanding resistance factors.
Area of Science:
- Sports Science
- Biomechanics
- Cycling Performance
Background:
- Understanding aerodynamic and rolling resistance is crucial for optimizing cycling performance.
- Field-based measurements offer a practical approach to assess these resistances.
Purpose of the Study:
- To develop a protocol for isolating aerodynamic and rolling resistances from field-based power and velocity data during cycling.
- To validate the use of commercially available power meters for detecting resistance changes.
Main Methods:
- Assessed effects of body position (brake hoods vs. drops) and tire pressure (414 vs. 828 kPa) on resistances.
- Measured power-versus-speed relationships using bicycle-mounted power meters under controlled conditions.
- Calculated aerodynamic resistance (k) and rolling resistance (Rr) from the power and velocity data.
Main Results:
- Aerodynamic resistance was significantly higher when hands were on the brake hoods compared to the drops.
- Rolling resistance was significantly higher at lower tire pressure (60 psi) versus higher tire pressure (120 psi).
Conclusions:
- Commercially available power meters are sensitive enough to detect changes in aerodynamic and rolling resistance.
- Modest changes in body position and substantial changes in tire pressure significantly impact cycling resistance.
- The developed protocol effectively isolates aerodynamic and rolling resistances in field settings.
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