The most common type of ankle sprain is called an inversion sprain. This is where the foot is plantarflexed (toes pointing down) and your ankle then rolls so the bottom of your foot faces inward. The reason this type of sprain is the most common is due to the anatomy of the bones of the ankle, collectively called the ankle mortise.
The ankle moretise is comprised of 3 bones. These include the tibia, fibula, and talus. As the tibia and fibula extend down into the ankle they form a dome like shape that allows the talus to fit right inside the dome. The talus is a small bone located above your heel bone. The talus, along with the tibia and fibula allow the primary motion of dorsiflexion and plantarflexion and secondary motions of inversion and eversion.
The shape of the talus is the reason why most sprained ankles occur when the foot is plantarflexed and inverted. You can think of the talus as the shape of a triangle. When the foot is dorsiflexed, the wide side of the triangle is tucked into the ankle mortise which allows less 'wiggle' room and therefore more stability and strength. When the ankle is plantarflexed the point of the triangle is now the only part in the mortise which allows more motion, but less stability.
The fibula also plays a roll in the stability of the ankle. At the distal end (the side closer to the foot) of the tibia and fibula there are two malleoli. The outside malleolus extends down farther than the inside malleolus. The length of the outside (or fibular) malleolus restricts the ability to evert your ankle.
Both the shape of the talus and the length of the fibular malleolus create the reason why most all ankle sprains are due to when the foot is plantarflexed and inverted.
Exercises should be performed after the acute phase of injury is done. Depending on the severity of the ankle sprain, this can range from days to weeks. During the acute phase, make sure to follow the PRICE guidelines for injures:
When the swelling and pain begin to decrease, this is when exercises should be introduced. Early induction of exercise plays a few important roles:
1) The sooner you rehab and begin introducing the range of motion in the ankle, the less chance of developing painful and restrictive scar tissue and adhesion.
2) After any injury atrophy occurs causing muscles to shrink and become weaker. The sooner you begin your rehab the less atrophy will occur and improved strength and stability will follow.
3) Exercise and motion reduces pain. This is a neurological component where your bodies mechanoreceptors will inhibit the pain signal traveling up to your brain. This is the reason that after you bump your arm, you immediately rub it or put pressure on it.
Excersises should include both mobilty and strength training componnents. Mobility exercises can include imagining writing the alphabet with your toes or simply taking it through an active and passive motion. Strength training ideally will work all ranges of motion: dorsiflexion, plantarflexion, inversion, and eversion. This can be done with flexible rubber tubing or calf raises. Another great exercises are balance discs. Balance discs force us to activate our stabilizer muscles in order to keep our balance.
All exercises recommended here should initially be perormed and monitored by a trained professional. The rule of thumb for all therapeutic exercises is that if it causes sharp, or discomfortable pain, then you are doing more harm than good. If you experience dull, manageable pain you can continue with the exercises. All in all, make sure you listen to what your body is telling you. You should never try to 'push yourself' through exercises that don't feel good.
Dr. Aaron Lowe
5400 Watt Ave.
North Highlands, CA 95660