Biomechanical Model Running

*speed up*

A larger vertical ground reaction force creates greater friction force and greater total external force to push against. Greater external force to push against allows greater ankle plantar flexion muscle force, knee extension muscle force, and hip extension muscle force to be exerted. 

Greater ankle plantar flexion muscle force creates greater ankle plantar flexion joint torque and greater ankle plantar flexion angular velocity. Greater ankle plantar flexion angular velocity creates greater linear speed of the ankle and all joints superior to the ankle.

Greater knee extension muscle force creates greater knee extension joint torque and greater knee extension angular velocity. Greater knee extension angular velocity creates greater linear speed of the knee and all joints superior to the knee.

Greater hip extension muscle force creates greater hip extension joint torque and greater hip extension angular velocity. Greater hip extension angular velocity creates greater linear speed of the hip and all joints superior to the hip.


This coordinated increase in joint linear speeds is the result of modifying a factor that speeds the body up (vertical ground reaction force) and results in greater linear speed for the runner and a decrease in movement time.

to create a larger vertical ground reaction force you must run on the hardest surface available

A larger coefficient of friction creates greater friction force and greater total external force to push against. Greater external force to push against allows greater ankle plantar flexion muscle force, knee extension muscle force, and hip extension muscle force to be exerted.

Greater ankle plantar flexion muscle force creates greater ankle plantar flexion joint torque and greater ankle plantar flexion angular velocity. Greater ankle plantar flexion angular velocity creates greater linear speed of the ankle and all joints superior to the ankle.

Greater knee extension muscle force creates greater knee extension joint torque and greater knee extension angular velocity. Greater knee extension angular velocity creates greater linear speed of the knee and all joints superior to the knee.

Greater hip extension muscle force creates greater hip extension joint torque and greater hip extension angular velocity. Greater hip extension angular velocity creates greater linear speed of the hip and all joints superior to the hip.

This coordinated increase in joint linear speeds is the result of modifying a factor that speeds the body up (coefficient of friction) and results in greater linear speed for the runner and a decrease in movement time.