The Influence of the Shape of the Cam Pulley on Leg Extension Machines

Abstract

The optimal design of leg extension exercise machines is crucial in effectively targeting and activating the quadricep muscles during exercise. This research paper investigates the shape effectiveness of the cam pulley on leg extension machines on the tension in the user’s quadriceps. This study surveyed three subjects for anatomical measurements, collected data using two different selectorized leg extension machines, and calculated the force and torque. The results provide insights into the function of the non-circular shape of the cam pulley in designing leg extension machines. This keeps the force on the shin pad consistent by applying more force during certain periods throughout the course of leg extension. With this insight, a design of a leg extension machine accounting for the differences in each individual’s leg weight is proposed.