Calcaneal Eversion: A Subtle, But Important Motion

by Chuck Wolf

The subtle, intricate actions of human movement are the individual links that compose the chain of human motion. Nothing is more important than the need for calcaneal eversion to set the entire chain reaction into motion by loading the muscles of the foot, calf, knee, leg, and hip. Without calcaneal eversion, inefficient motion occurs and overuse can soon follow.

In gait, the foot lands on the lateral aspect of the calcaneus as gravity and ground reaction forces cause the heel to turn laterally, or more accurately, eversion. Along with gravity, ground and reaction forces the eccentric control of the anterior tibialis, peroneals, and the extensors of the toes lower the foot to the ground. As the calcaneus everts, the subtalar joint abducts, the ankle dorsiflexes, and tibia internally rotates, thereby creating a tri-planar motion at the ankle. The anatomical structure of the ankle complex makes the ankle, which dorsiflexes and plantar flexes in the sagittal plane, a perfect complement to the subtalar joint which functions in the frontal and transverse planes. The posterior calf group, especially the posterior tibialis, lengthens to decelerate and control these actions. As the calcaneus everts during pronation of closed chain activities, the midtarsal joints invert, abduct, and dorsiflex in relation to the subtalar joint and rearfoot to allow proper absorption of forces through the foot. When the tibia moves over the foot, the soleus decelerates tibial motion in the sagittal plane and the gastrocnemius helps control tibial rotation in the transverse plane. The chain reactions that follow are knee flexion and abduction, hip flexion and internal rotation which absorb the forces of the body and gravity. The eccentric tri-plane actions of the calf, quadriceps, and hip musculature must load to control these forces before any effective actions can transpire.

Therefore, based upon these principles, in order to recruit the gluteals in three planes of motion, the foot must go through pronation which creates the eccentric loading of the entire chain. This stores energy and enhances the muscle’s ability to successfully supinate and accelerate propulsion and explosiveness. No matter what stage of life or activity that is pursued, the subtle calcaneal eversion sets the environment for efficient movement that is energy efficient and reduces risk of injury.

The fitness professional should become familiar with these functional actions, as inefficient actions of the foot, i.e. flat or high arched feet, can inhibit the foot’s ability to attain the proper loading and ultimately limit the person’s ability to have a strong propulsive unloading or supination.