Changes in saddle setback and intensity affect comfort and lower limb kinematics in recreational cyclists

Cycling offers numerous health benefits. However, an improperly adjusted saddle setback can lead to discomfort and injury. There is limited evidence about the effect of intensity and sex when manipulating saddle setback. The present study analyzes how saddle setback, pedaling intensity and sex impact on comfort, perceived exertion, and lower limb kinematics in recreational cyclists. Thirty-four (N = 34) recreational cyclists (14 women and 20 men) were measured. Cyclists performed the same protocol on a cyclergometer under 3 different saddle setbacks (preferred, forward, backward) and 2 pedaling intensities (first and second ventilatory thresholds, VT1 and VT2). Perceived exertion was only significantly increased during VT2, compared to VT1 (p < 0.05) and comfort was lower at backward saddle setback compared to forward saddle setback and preferred condition (p < 0.05). Angular kinematics showed significant differences (p < 0.05), mainly influenced by saddle setback and intensity. A more rearward saddle position (+ 10%) resulted in greater extension across all joints, while higher intensities (VT2) led to reduced hip flexion and increased ankle dorsiflexion. The multiple linear regression analysis showed the existence of a relationship between the variables of the cyclist's height, saddle height, inseam length, and foot length. Therefore, a new equation for adjusting saddle setback was calculated from the present study. A greater saddle setback increases knee and ankle joint extension and reduces hip flexion-extension, especially at higher intensities, while also decreasing comfort without significantly affecting perceived exertion.