In our first post regarding pronation, we discussed how pronation affects static posture. Today we’ll discuss how pronation affects dynamic movement, particularly the lower extremities. As the foot pronates and the midfoot rotates medially (inward), the knee also rotates internally. This alone may not seem like a big deal when dealing strictly with posture, but the real damage is occurs during movement.
When people pronate they tend to stand with their feet pointed outwards due to their internally rotated knees. In order to stand in a way that takes stress off the knees, the feet must point outward: if the feet are parallel, the knees will be at an oblique angle towards the midline, which is uncomfortable for most people. Therefore, to keep the knees pointing straight forward, the toes must turn out.
As a result, people who pronate tend to roll around the ball of the foot instead of rolling through it when they walk. As seen in the video, the pronated foot begins to roll inward (during the mid-stance phase of the gait cycle) before the heel leaves the ground, whereas the corrected foot remains stable. As the foot remains stable at the ankle and midfoot, it can then move through the ball of the foot instead of rolling around it (during the heel-off phase of the gait cycle). Due to this change in gait a person can develop any combination of the following issues: bunions, plantar fasciitis, neuromas, Achilles tendonitis, lateral ankle pain, knee pain, IT band or piriformis syndrome, low back or neck pain and poor posture and balance.