Overpronation is the excessive pronation of the foot. Pronation movement is part of the normal gait cycle.
Pronation occurs as weight is transferred from the heel to the forefoot and the foot rolls inwards. Pronation is a movement of the subtalar joint (the joint between the talus and calcaneus, talus is on the top so it is called subtalar joint) into eversion, dorsiflexion, and abduction resulting in sole being turned outwards, upwards and sideways.
Pronation helps to provide shock absorption at the foot. The opposite movement to pronation is supination. This is reverse movement consisting inversion, plantar flexion and adduction making the sole of the foot inwards, downwards and sideways.
People with overpronation of the foot during walking or running are susceptible to overuse injuries.
Overpronation can cause overuse type injuries, especially in runners. Overpronation during walking or running leads to increased internal rotation of the leg, knee, and thigh, the stresses on the muscles, tendons, and ligaments of the foot, leg including shin and knee.
Neutral Pronation, Overpronation or Underpronation
During normal gait, the forward movement displaces body’s mass puts the body in a forward-falling position. Then, the front foot hits the ground preventing the fall, followed by the rear leg as it swings forward, and the cycle repeats.
On hitting the ground, foot works to absorb and dissipate the shock of impact. The foot pronates to accommodate the ground surface contour. The ankle goes into dorsiflexion allowing the knee to move forward, and the body follows. Following this, the heel raises, and the foot supinates becoming a rigid lever that aids in the pushing action that eventually ends with the toe-off. Thus, first, the foot pronates after a ground strike and supinates in preparation for push off.
Foot pronation and supination are a help to minimize the forces that the body is subjected to during walking or running, and to create the lever that is needed for propulsion.
Neutral pronation occurs when the foot experiences a normal, healthy amount of pronation instead of overpronating or underpronating.
Neutral pronation is characterized by even distribution of the weight fairly evenly among all of the toes with a slight emphasis on the big toe and second toe.
In a person with foot overpronation, the push off is almost completely from the big toe and second toe. Due to this, the shock from the foot’s impact doesn’t spread evenly throughout the foot. In an attempt to stabilize the body, the ankle comes at an unnatural angle with the foot and the foot splays out abnormally. [watch video]
Causes of Overpronation
Following entities have been found to be associated with overpronation –
- Tibia vara>10 degrees
- Leg length discrepancy
- Ligamentous laxity
- Week/tight gastrocnemius and soleus muscles.
Effects of Overpronation
Overpronation leads to increased rotation of the tibia, which may result in the lower leg or knee problems. Overpronation is usually associated with many overuse injuries in running including medial tibial stress syndrome, or shin splints, and knee pain.
How to Check for Overpronation
- While standing, if you cannot see the inner arch and innermost part of the sole touches the floor, then your feet are overpronated.
- If your shoes wear out more on the inside of the sole, you might have overpronation.
- Wet your feet, walk and look at the footprints. A normal foot will leave a print of the heel, connected to the forefoot by a strip approximately half the width of the foot on the outside of the sole. If your feet are pronated there may be little distinction between the rear and forefoot.
The best way to determine if you overpronate is to visit an expert.
Correction of Overpronation
Shoes and Orthotics
If you overpronate, get a shoe with extra medial support. Many running shoes have a harder material on the inside of the midsole making shoe compress less under load and prevent it from rolling in or flattening.
Orthotic insoles is another option.
Pronation also decreases significantly when the highest number of eyelets in the shoe is used for lacing and the shoes are tied as tight as possible.
Certain methods of taping the foot and leg have also been shown to be effective in preventing overpronation.
Running barefoot can decrease pronation because running shoes have extra weight for cushioning at the heel of the shoe, causing the runner to heel-strike more, which in turn results in increased pronation during the step.