When we are standing and weight is forward on the feet, there is a gentle stimulation of the inter-osseous reflex of the positive supportive response, which triggers leg extension and extension of the spine, a healthy outward response to gravity which keeps the body adaptable and ready for movement. Briefly, this response is stimulated when the muscles between the metatarsals are stretched by the weight of the body causing the forefoot to spread. When we extend ourselves forward to walk or to run, this reflex comes more strongly into effect, and the legs and spine extend actively in locomotion.

If, on the other hand, the body’s weight is placed on the heels – either as heel strike or after forefoot strike, one tends to see protective, retractive reflexes activated as a protective response against falling. In running, if a leg is naturally recovered from spinal and pelvic rotation the foot will move forwards with the ankle lightly extended and the toes dropped so that the forefoot is placed on the ground to take the weight of the leg, and then the body as it moves forward. When this is allowed, the extensor reflex will be increasingly engaged through foot contact, midstance, and into extension. If the body’s weight is placed on a heel at any point in this progress, extension of the trunk and leg will be lost, and other learned muscular actions, such as hamstring and gastrocnemius contraction, will be necessary for forward movement.