Effects of saddle-height setting methods and fatigue on lower-limb kinematics during indoor cycling in recreational cyclists

This study aimed to investigate the effects of different saddle height setting methods and fatigue on lower limb kinematics during indoor cycling in recreational cyclists. Twelve recreational male cyclists completed indoor cycling randomly using three saddle height setting methods—trochanteric length method (TLM), LeMond method (LMM) and knee angle method (KAM)—performed a fatigue protocol. Sagittal-plane ankle, knee and hip kinematic data were collected. Extracted ankle, knee and hip angles at top dead center (TDC), bottom dead center (BDC) and range of motion (ROM) for data analysis. A two-way repeated-measures ANOVA was conducted to examine the main effects of saddle height, fatigue and their interaction. This study found that saddle height setting methods significantly influenced ankle and knee kinematics. Compared with KAM and LMM, TLM resulted in greater ankle ( p = 0.01) and knee ( p = 0.01) ROM, as well as reduced knee flexion at TDC ( p = 0.01) and reduced knee extension at BDC ( p = 0.01). Fatigue significantly reduced ankle ( p = 0.02) and hip ( p = 0.01) angles at TDC but did not affect knee kinematics. A significant saddle height × fatigue interaction was observed only for hip range of motion ( p = 0.04), with a post-fatigue increase occurring exclusively under LMM condition. Saddle height setting methods substantially influence lower-limb kinematics during cycling, while fatigue induces joint-specific adaptations. Recreational cyclists should consider that different setting methods produce distinct effective heights that influence joint responses to fatigue.