Every day in the United States, 23,000 people sprain their ankles. More than two-thirds of those folks will end up with CAI. There are several theories to help explain the mechanism behind chronic sprains.
Mechanical factors, such as the change in tissue tension around the ankle when a ligament is sprained, have always been part of the picture. But this is only one factor. Another is the loss of normal sensorimotor responses.
This refers to the ankle joint’s ability to receive and interpret neurologic information about sensation and movement. This is the neurologic side of ankle injury and instability. A decreased awareness of the foot and ankle position (especially with changes in the ground or surface we are walking on) contributes to repeated ankle sprains.
Using a rocker or wobble board is an effective way to help restore neural pathways and regain more normal proprioception (joint sense of position) and kinesthetic awareness (sense of movement through space).
It resensitizes the sensory and motor nerves. The effect is to increase messages to the motoneuron pool in the spinal cord. When there’s enough excitability in the motoneuron pool, messages are sent to contract the muscle(s). A lack of motoneuron pool excitability means the muscles don’t contract to protect the joint and accommodate to a change in position. This puts a strain on the ligaments that are already damaged an increases your risk of repeated injuries.
It takes a while to re-establish all of the proper neural pathways from joint to muscle and muscle to spinal cord then back to the muscle and joint. The rehab program usually starts with a less difficult activity such as rolling a ball under the foot or using the rocker board in a seated position. When the joint receptors have been retuned in this fashion, then the program adds strengthening of the muscles around the ankle.
Combining these two components of the rehab program allow you to progress to the more difficult upright standing balance activities. At first, the rocker board is used under the injured foot but while still standing on the other leg. Eventually, you will move to a one-legged stance (injured foot on the board) while holding onto a support. The final step is to balance one-legged without holding on.
If you have missed any of these steps, you must back up and start again. A physical therapist can assist you with this process. After testing your muscle strength, proprioception, and sensorimotor function, the therapist will know what level you should be at and how to move you through the program successfully.