The muscles that control the foot by and large originate in the lower leg. Yes, there are a few muscles originating on the bottom of the foot known as the intrinsic muscles of the foot, but the major motion of the foot begins in the lower leg.
The muscles directly in the back of the lower leg control the achilles tendon and that aids in movement of the ankle up and down. The muscles in the back and more to the inside of the leg also help move the ankle, but possibly more important they help to raise the arch of the foot at a certain point in the gait cycle.
The muscles on the outside of lower leg aim to dorsiflex the foot (bring it upwards) and to stabilize the great toe joint as the foot pushes off. Again these functions occur at specific intervals during gait.
Lastly the lower leg muscles in the front of the leg also bring the foot up as the foot moves forward in the gait cycle and then slows the speed at which the front part of the foot comes down after the heel hits the ground.
In some individuals who excessively pronate (feet over flatten during the gait cycle), the muscles of the lower leg may be forced to "over work" and this can lead to problems. This is because as I just mentioned the lower leg muscles all serve a specific purpose at a specific point in the gait cycle. If there more motion in the foot than "norma", the muscles controlling the foot function are forced to over function and this will lead to pain.
Then, there are individuals who supinate (feet stay fairly rigid during the gait cycle) and this causes pain in the legs primarily related to the fact that a supinated foot is a poor absorber of shock. Shock absorption along with forward ambulation are the two main functions of the feet. So, pain in the legs, even the joints of the knee and hip, in addition to the lower back may all be related to a foot issue.
In any complaints of pain originating from the lower back all the way down to the feet, the function of the feet in the gait cycle should be examined and ruled out as the source of the pain. If, however, it is noted there is a problem with a person's gait cycle that is leading to pain in the leg, an orthotic is usually the answer.
In this section I am going to discuss some of the conditions that may cause pain in the leg but is actually originating from abnormal foot function. The majority of these foot issues are known as biomechanical problems. In other words they are a result of the way the foot, ankle and leg function as a unit.
Sometimes these problems will not be evident in every day life, but will become a problem when there is a life style change such as participating in a sport, or a change in occupation where you go from a sedentary existence to having to do a lot of walking on a daily basis. At times these issues may be due to nothing more than wearing the wrong type of shoe for the task at hand, but if changing shoe style does not alleviate the pain, one needs to look beyond that for the cause.
One thing most of these conditions that I am going to discuss is the fact that the pain will be activity related. In general terms if the leg pain is its greatest when active and then either subsides completely or reduces a great deal when resting, there is a good chance the problem is a biomechanical problem and an orthotic may end up being very helpful.
how does an orthotic help leg pain?
If we can control the way a foot functions in the gait cycle we can better stabilize it and have it function in a more normal circumstance. If the foot is functioning in a more normal range of motion, this will lead to a reduction in the work the muscles of the lower leg have to undergo and a result they will not fatigue.
Aside from muscles being forced to over work, an abnormally functioning foot also creates issues at the ankle, knee and hip joint. Excessive pronation, for example can create an abnormal alignment of the ankle joint, knee joint and to a lesser extent the hip joint.
It is important to note that not only do the muscles of the lower leg control the function of the foot in gait, but those same muscles are designed to work in conjuction with the muscles of the upper leg (thigh) as well as the hip muscles and muscles of the lower back.
Thus by adding an orthotic we are able to create a better alignment all the way up the leg; better alignment means better foot and leg function.