Graduation Date

Spring 2026

Document Type

Thesis

Program

Master of Science degree with a major in Kinesiology

Committee Chair Name

Sarah Landis

Committee Chair Affiliation

Cal Poly Humboldt Faculty or Staff

Second Committee Member Name

Justus Ortega

Second Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Third Committee Member Name

Rock Braithwaite

Third Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Keywords

Cycling, Bike fit, Saddle tilt, Upper body muscle activation, Gross efficiency, Uphill

Subject Categories

Kinesiology

Abstract

Cycling is a globally popular activity for transportation, health, and sport. Proper bike fit can improve performance and reduce injury risk, yet its influence on muscle activation and cycling energetics remains unclear. In particular, the impact of saddle tilt on cycling economy [gross efficiency (GE)] and upper-body muscle activation during uphill cycling is not well understood. On steep inclines, a saddle pointed upward may require greater upper-body muscle activation for stabilization and to prevent backward slippage. This study examined how saddle tilt affects cycling economy and upper-body muscle activation during climbing. We hypothesized that a leveled (downward-tilted) saddle would reduce upper-body muscle activation and improve GE.

Eighteen recreational cyclists completed two laboratory sessions: a VO₂max test to determine relative exercise intensity, and an experimental session with eight five-minute trials at varying grades (10 percent, 20 percent), intensities (50 percent, 70 percent VO₂max power), and saddle conditions (parallel, tilted). Indirect calorimetry measured oxygen consumption and carbon dioxide production to determine GE, and surface EMG assessed upper-body muscle activation.

The tilted saddle condition increased GE compared to the parallel saddle, with a more pronounced effect at the 20 percent grade, where GE improved by ~3 percent (tilted: 0.204 ± 0.020; parallel: 0.198 ± 0.011; mean difference = −0.006, 95% CI [−0.012, 0.000], p = 0.036). Global EMG was reduced by ~18 percent at a 20 percent grade (tilted: 4.09 ± 1.67; parallel: 4.97 ± 1.93; mean difference = 0.88, 95% CI [0.15, 1.61], p = 0.021).

These findings suggest that saddle tilt may modestly improve cycling economy on steeper slopes, potentially through reduced upper-body stabilization demands.

Citation Style

APA

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