Walking on the outside of the foot, known as excessive supination or underpronation, occurs when the foot rolls outward too much during the walking or running cycle. While a small degree of supination is natural, an exaggerated outward roll means the foot is not properly absorbing impact. This dysfunctional movement shifts the body’s weight, concentrating stress on the lateral side of the foot and up the kinetic chain. Addressing this issue involves external supports and active physical re-training to correct alignment.
Identifying Excessive Supination and Its Causes
Excessive supination is defined by a prolonged outward roll of the foot, where the majority of the weight is borne by the outer edge. This differs from normal gait, which involves a brief period of supination at toe-off. The primary concern is that excessive supination limits the foot’s natural ability to pronate, which is the necessary inward roll that acts as the body’s shock absorber upon landing.
One common underlying reason for this gait pattern is inherited foot structure, particularly having naturally high, rigid arches, sometimes called pes cavus. This high arch shape makes the foot less flexible and less capable of collapsing slightly to absorb impact, predisposing the person to supination. Structural imbalances can also contribute, such as differences in leg lengths or a previous ankle injury that altered the walking pattern.
Muscular factors play a significant role in perpetuating the outward roll. A tightness in the calf muscles or the Achilles tendon can restrict the ankle’s range of motion, forcing the foot to land and remain on its outer edge. Conversely, weakness in certain lower leg muscles, particularly the peroneal muscles, which control the foot’s ability to turn inward (eversion), can prevent the foot from properly transitioning into pronation. These muscular imbalances, combined with the structural limitations of a high arch, establish a cycle of improper alignment.
External Solutions: Footwear, Insoles, and Bracing
The immediate and most accessible intervention for managing excessive supination involves external supports that passively manage foot positioning. Proper footwear selection is the most important step; people who supinate should seek out neutral, well-cushioned shoes. These shoes are designed to maximize shock absorption throughout the midsole to compensate for the foot’s limited natural shock absorption.
It is important to avoid stability or motion-control shoes, as these are designed to prevent excessive inward rolling (overpronation) and would only exacerbate the outward roll of a supinator. The ideal shoe for supination should also offer a wide toe box and extra cushioning in the heel area to better accommodate the high arch and absorb the concentrated impact on the lateral heel. Look for shoes with a soft, flexible midsole that encourages the foot to roll inward slightly.
Orthotic insoles or arch supports are another effective external solution, working by distributing pressure more evenly across the sole of the foot. For supinators, orthotics should focus on providing cushioning and flexible support, rather than rigid correction, to encourage the foot to utilize its full surface area. Custom-made orthotics can match the contours of a high arch, providing targeted support and improving alignment. Temporary ankle bracing or athletic taping can provide mechanical stability in acute situations, such as recovering from an ankle sprain, but this is not a long-term solution for correcting the gait pattern.
Targeted Exercises for Gait Correction
Active intervention through targeted exercises is necessary to create lasting change in the gait pattern by strengthening and stretching specific muscle groups. Since excessive supination is often linked to tightness in the calf and Achilles tendon, regular stretching of these structures is important. Calf stretches, performed with the back leg straight and the heel firmly on the ground, help to restore the ankle’s dorsiflexion mobility, which is the movement needed to flatten the foot.
Strengthening exercises must focus on the muscles responsible for controlling the inward roll of the foot, particularly the tibialis anterior and tibialis posterior muscles. Simple drills like “pen lifts,” where the toes are used to grasp a small object, help to improve the fine motor control and strength of the foot intrinsic muscles. Resistance band exercises that involve pulling the foot inward (inversion) can directly engage the tibialis posterior, which is an important stabilizer during the stance phase of walking.
Balance and single-leg stability drills are also highly effective for improving overall foot and ankle control. Practicing a single-leg stance forces the foot and lower leg muscles to stabilize the body, retraining the ankle to resist the tendency to roll outward. When focusing on walking itself, a technique known as mindful gait retraining can be implemented; this involves consciously trying to land closer to the midfoot rather than the heel, aiming for a flatter foot strike and a shorter stride.
Injuries Associated with Walking on the Outside of the Foot
The lack of proper shock absorption caused by excessive supination increases the risk of various lower body injuries. When the foot fails to roll inward, ground reaction forces are not dispersed effectively, leading to a concentrated impact that travels up the leg. This repeated stress can cause stress fractures in the metatarsals (the long bones in the foot) or lead to shin splints along the lateral side of the lower leg.
The constant outward positioning of the foot creates lateral instability, making the ankle highly susceptible to sprains when walking on uneven surfaces. The strain on the foot’s connective tissues can also lead to conditions like plantar fasciitis, which is inflammation of the thick band of tissue across the bottom of the foot. Misalignment starting at the foot often extends upward, resulting in pain in the knee, hip, and lower back as the body compensates for the altered mechanics.