When we are walking the range of movement available at the ankle joint is really important. Whenever we place the foot on the ground the body above has to move forward above that foot. That forward movement occurs at the ankle joint, therefore it ought to be clear that there ought to be nothing which stops that forward motion at the ankle. Disorders such as osteoarthritis within the ankle joint can impact that forward motion. Another frequent problem which can hinder that forward movement are tight calf muscles. They stop the leg moving the required range of motion above the foot. In the event that motion is restricted than a number of things may occur. Firstly, walking is quite a bit more difficult. It is more tiring as far more efforts are necessary to walk. Secondly, your body needs to obtain that motion from somewhere. When it is unable to get that movement at the ankle, then it might get it in the knee and when that occurs we then walk with a more flexed knee which is actually a difficult way to walk. If the body doesn’t compensate at the knee, then it gets the motion at the midfoot. If that happens then the arch of the foot flattens and that can lead to a variety of clinical disorders.
For these reasons, doctors prefer to look at the range of motion at the ankle joint as part of a biomechanical examination. There are several ways of doing this. One of the ways is a non-weightbearing examination with the foot and leg up in the air and the feet are just moved on the lower limb and the range of motion is assessed. Another, possibly better way, is to do what is known as a lunge test. This is a weightbearing measure of the ankle joint range of motion and in that position it is probably a better representation of the reality of the way that we walk.