Overview of Running

Anatomy

Isolating the process of running to the lower extremities for the brevity of this page, the most important structures are the major bones of the legs and feet (Femur, Tibia, Fibula, Patella, Calcaneus, Tarsals, and Metatarsals). Together with the major movers of the lower extremity (Gluteus Maximus, Gluteus Medius, Quadriceps group, Biceps Femoris, Semitendinosus, Semimembranosus, Gastrocnemius, Soleus, and Anterior Tibialis) create the most important joints for running (Patellofemoral, Glenohumeral, Tibiofemoral, Talocrural, Subtalar, and Tarsometatarsal(s)). 

Biomechanics

Running is a series of controlled falls that are intermittently caught by a single leg, almost a series of hopping. Running occurs as a motion through the frontal plane about a medial-lateral axis. Each leg goes though two distinct phases while running stance and swing. When a foot is in the stance phase (planted to the ground) the joints about the ankle are taking a dorsally acting force and applying muscular action in the plantar direction, this activates the triceps surae. The knee is in a slightly flexed, but almost fully extended position, and from beginning to the end of the stance phase will extend, activating the quadriceps, producing patellar glide. The hip joint begins in a flexed position and extends through the stance phase activating the Biceps Femoris and Gluteal muscles. At the same time during the swing phase, the muscles are more relaxed and the joints are not experiencing any transfer of force. But, to cycle through and reach the next stance phase, the quadriceps will have to flex, bringing the hip joint into slight flexion. At the same time these muscles are pulling the knee closer to an extended position and the Anterior Tibialis dorsiflexes the ankle to prepare the leg for another strike at the ground.

This process repeats continuously 150-170 times per minute for an average runner.