Biomechanical Modeling of Gluteus Maximus Contribution to Pedal Torque

Resumo

This work presents a biomechanical model of a cyclist in the sagittal plane, simulating the motion of the leg and pedal based on a four-bar linkage mechanism. Inverse kinematics is used to determine the positions of the lower limb segments throughout the pedaling cycle, and the force calculations are performed using inverse dynamics. A system of linear equations is formulated to compute joint reaction forces and the crank torque from joint moments. The Gluteus Maximus muscle is modeled using real anatomical data such as physiological cross-sectional area (PCSA), specific muscle tension, muscle activation, and the behavior of the muscle’s moment arm over the femoral head. Muscle force is estimated using a Hill-type model, where muscle elongation is considered in order to represent the nonlinear behavior of the muscle–tendon unit. The resulting analysis allows the evaluation of the torque generated by the Gluteus Maximus during the pedaling cycle, enabling the identification of optimal activation positions and the instants where the activation will produce isometric contractions that do not contribute to the generation of crank torque. This analysis is especially important when designing the bicycle frame and its drivetrain to ensure efficient load transfer throughout the pedaling motion.