Forefoot Varus and Overpronation

Working over the last several months to correct my own problems with ovepronation has been a learning experience. During each stage of this process I discovered new issues to target, the latest one being forefoot varus. Luckily, most of the problems, like ankle mobility and calf flexibility, are interrelated. Improvement in one area indirectly benefits all the others. I’ve been extremely satisfied with my progress up to this point and plan to continue working on arch strengthening and gait mechanics as long as I continue to see positive changes.

To start, here’s a comparison of my standing foot and ankle positioning at the start of this project and today:

June 4, 2012

Oct 12, 2012

The biggest change you can see from this angle is the alignment of the heels. In the before picture both heels are everted, or turned outward. You can also see how the Achilles tendon curves on its path from the heel up toward the calf.

In the recent photo my heels are a lot less everted and the Achilles lines up straight. Excessive eversion is one of the measurements used to determine if someone is overpronating and as you can tell from the before pictures, an excessively pronated, collapsed arch position was my default standing alignment. Essentially, flat feet.

Now that my heels (rearfoot) are in a more neutral position I’ve noticed a change in the positioning of the forefoot. Specifically, the inside part of the ball of my foot (the underside of the knuckle of the big toe) is not making as solid contact with the ground as it was before. When I walk, particularly in stiff-soled shoes, that the big toe often isn’t pressing very hard into the ground.

This is a concern because the foot is designed to function like a tripod. Having three solid points of contact allows the foot to be both more stable and more responsive. The reason my big toe is lifting up with the decrease in heel eversion is because of the altered way the forefoot is angled on the rearfoot, a positioning known as forefoot varus. Tackling this problems seems like the reasonable next step on the path toward better mechanics.

Alignment

Forefoot varus is the angling or inverted position of the bones in the front of the foot in relation to the heel. In an uncompensated forefoot varus deformity, this causes the bones on the inside edge of the foot to sit higher off the ground than the outside of the foot during weight bearing.

As I mentioned eariler, the preferred position of the foot is a tripod, so the body often compensates to make a third contact with the ground by way of everting the heel outward to bring the plane of the toes level with the ground. It is this compensatory mechanism for the varus forefoot that contributes to overpronation.

Some degree of forefoot varus is common. A study of healthy individuals published in the Journal of Orthopaedic and Sports Physical Therapy found out of 120 subjects, 87% had a varus forefoot-rearfoot relationship. Other studies have reported similar findings, for the most part, although some variability among percentages may be related to the different methods used to measure the varus angle.

Such a high prevalence raises the question whether this is abnormal. My answer is a tentative yes. That is because these studies do not tell us if the varus is something people acquire during their lifetime, or whether they are born with it. This is a question that should be asked when attempts are made to describe the characteristics of a normal foot because, as I’ve brought up in previous posts, we cannot discount the effect lifelong shoe wear has on the positioning and mechanics of the foot.

I think there is a good chance that footwear alters the shape of the foot so that what scientists are really examining in studies of so-called “normal” subjects are joints that have been influenced by shoes and not really indicative of how the foot would normally appear and function.

It’s well understood how forefoot varus causes overpronation, but it’s less clear the relationship between overpronation and injury. This is an area that requires more research, but I don’t see how the altered alignment and joint mechanics associated with overpronation could not be a risk factor, particularly for overuse type injuries. There is some evidence that forefoot varus is associated with both hip pain and patellofemoral syndrome. There is no downside to working on this issue and there’s the potential for a huge upside if it means warding off injuries and degenerative joint problems, so that’s enough incentive for me to explore the issue.

Gait

The picture to the left is another illustration of how a forefoot varus can lead to excessive pronation during the stance phase of the gait cycle. The dotted lines represent the position of the toes and the colored lines representing the angulation of the heel and forefoot. The everted heel position at mid stance looks very similar to my foot position in the before photo posted above.

A small amount of pronation is a part of the body’s natural shock absorption system. The amount of heel eversion that is considered excessive I’ve seen reported as anywhere between 8 and 15 degrees. At a certain point, too much pronation will not only pull the rest of the leg out of good alignment, but it will also limit the foot’s ability to function as an efficient and effective arch.

The two ends of the medial arch are the heel and the base of the big toe. Both rely on the strength of the muscles in the foot and around the ankle to hold them in position and prevent the arch from collapsing under the weight of the body. There are other things you can do to reduce the load on the arch, like increasing ankle dorsiflexion mobility, but I want to limit this discussion to correcting forefoot varus.

Can The Varus Angle Be Changed?

The forefoot varus angle is only going to respond to corrective exercises if muscle weakness and soft tissue tightness are the cause. Since I’m able to bring my foot into a level position with effort I know the problem is soft tissue related and not structural. I suspect the majority of cases are this way with the rare exceptions being instances where the bones themselves are in a position that block this movement.

I couldn’t find any information on what percentage are flexible vs rigid, and I think part of the reason is traditionally this problem has been treated with orthotics that build up the space underneath the foot to fill in that gap so there really hasn’t been much interest in seeing what could be done to fix the problem.

I’m not a big believer in orthotics and think the science behind them is flawed in several ways, especially when it comes to correcting overpronation. My main reason for creating this site was to show that exercises could be used as more reasonable and effective way to manage the problem, ultimately restoring the body’s own ability to control pronation.

The goal of an exercise for forefoot varus then is to strengthen the muscles that pull the base of the big toe down to the ground to stabilize the arch, while the heel is held in a stable position to prevent it from everting. This will involve some of the intrinsic muscles in the sole, like the flexor hallucis brevis, and a few of the calf muscles with tendons that influence the arch.

In some ways this is what the short foot exercise does. Breaking down that movement into separate components, though, seems to allow for better isolation of the muscles at work, so I’m hoping doing so leads to faster improvement.

The exercise I felt was the most effective, and the one I’ve decided to perform, involves first inverting (turning in) the heel slightly and then actively pressing the big toe down into the ground. The ball of the big toe (the metatarsalphalangeal joint) is what forms the tripod so it’s important to avoid curling or gripping with the toes as that would work different muscles and defeat the purpose of the exercise. Here’s a video demonstrating the movement:

Hopefully this gives you the general idea (I’ve just starting doing the exercise so don’t be too critical). After only a few repetitions this really starts to burn. I’m lifting the other four toes up while pressing the big toe down because I feel better isolation of the target muscle groups that way, though the exercise could also be done without lifting the rest of the toes. Also, from the same start position, toe abduction (moving the big toe away from the second toe) can be added to target the abductor hallucis, another important arch stabilizer muscle. Making firm ground pressure with the underside of the big toe is the basic concept of varus correction and ideally should also be practiced during normal walking so that the strength gains achieved by doing the exercises will translate over into better gait mechanics.

You might also like:

What is Pronation? Arch Strengthening to Control Overpronation Intrinsic Foot Muscle Strengthening For Overpronation And Pes Planus Basic Foot Maintenance