Author(s): FUCHS, P.X., HUANG, H.C., LEE, Y.S., SHIANG, T.Y., Institution: NATIONAL TAIWAN NORMAL UNIVERSITY (03735202), Country: TAIWAN, Abstract-ID: 1070

INTRODUCTION:
Cycling is widely incorporated into rehabilitation and therapy regimes due to small joint loads and force impacts. Posture and pedaling strategy (e.g., resistance, cadence) play an important role in force distribution as they affect cycling mechanics. Previous research debated about posture-dependent pressure in wrists and hips, potentially causing inflammation and muscle strains. Additionally, pedaling strategies have been linked to risks of knee injuries. Therefore, the purpose of this study was to investigate the effects of posture and pedaling strategy on kinetics at the pedals, saddle, and handlebar.
METHODS:
Twenty healthy adults completed a cycling test on a training stand in three riding postures (standard, sports, comfort) and six pedaling strategies (three cadences: self-selected and self-selected±10 rotations/minute; two resistances: heavy and light) in randomized order. A corporate, strain gauge-based measurement system (50 Hz; Giant Manufacturing Co. Ltd., Taiwan) was integrated into the pedals, the saddle, and handlebar grips to collect vertical forces, force distribution among the five sensor locations, and vertical impulse during the downstroke phase. Fifteen consecutive stable pedaling cycles (i.e., cadence fluctuation<5 rotations/minute) during each condition were analyzed. Repeated measures two-way ANOVA examined differences between postures and pedaling strategies at a significance level of p<0.05.
RESULTS:
Peak forces differed between postures at both handlebar grips [F(2,18)=5.58–31.62, p<0.01] but not at the saddle and pedals [F(2,18)=0.29–1.86, p=0.19–0.66]. No differences between postures were found in force distribution at any of the sensor locations [F(2,18)=0.42–1.11, p=0.35–0.67]. Impulse differed between postures at both handlebar grips and the left pedal [F(2,18)=4.12–10.13, p<0.05] but not at the saddle and right pedal [F(2,18)=0.61–1.07, p=0.36–0.55]. Pedaling strategy affected peak forces, impulse, and force distribution across all sensor locations and postures [F(5,45)=2.73–399.09, p<0.05], with the highest values occurring at high cadence and heavy resistance.
CONCLUSION:
The observed effects of posture and pedaling strategy on kinetics should be interpreted in the context of individual needs. In a therapeutical context, patients with upper body (e.g., wrist) injuries may select the comfort posture to reduce peak forces and impulse at the handlebar, thereby avoiding overload-related risks in the upper extremities. In addition, light resistance contributed to reduced peak forces and impulse at all sensor locations, irrespective of posture. The findings can be consulted to optimize cycling protocols in various settings where peak forces, force distribution, and impulse play an important role.

Acknowledgment: This work is supported by "The Application of Cycling Science in Sports and Health" of the National Science and Technology Council in Taiwan, R.O.C. under the grant number "NSTC 112-2622-8-003-005-SP".