When we land, our feet take an impact up to 3x of body weight. Our feet pronate naturally to cushion the impact.
Eversion and Invesion
- At initial ground contact, as the foot prepares for landing, it locks itself to take the shock of impact. Also known as Supination, the foot is not stable at this stage. Rearfoot is at an angle, called Inversion.
- The foot loosens up at mid-stance and arch touches the ground fully to stabilize the body. Known as pronation, at this position, rear-foot is at an angle called Eversion
- Foot locks itself (supinates) again to assist the body to propel forward. Rearfoot inverts to take off.
Excessive Eversion(Overpronation) and Running Injuries
Eversion angles of more than 18 degrees are correlated with higher occurence of foot injuries such as Achilles Tendonitis and Plantar Fasciitis. Excessive eversion also puts knee in awkward position during stance, often is the cause of Runner’s Knee (Patellofemoral Pain Syndrome)
What causes excessive eversion angles?
- Weak Inner-Calf Muscles (Tibilias Posterior) : Inner-calf muscles control the ankle movement and support the foot Arch. Weakness here causes excessive eversion of rearfoot.
- Feet with low arches (Flat feet) : Foot with low arches, and weak calf muscles causes excessive eversion.
- Lack of mobility in calf muscles & ankle joints :Tight calf-muscles and reduced ankle mobiilty interfere with foot pronation and cause excessive eversion of rearfoot
Runners often take the route of using stability or motion control shoes. But using such shoes can further complicate the issue. It is recommended that understand the underlying cause of excessive eversion and work on it accordingly.
Compiled by Team GeeksOnFeet for the love of running!
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