Gait mechanics rely heavily on the structure of the foot, which acts as the body’s foundation. Understanding the relationship between foot structure and movement patterns is important for maintaining overall foot health and preventing related injuries. When the foot’s natural arch is compromised, it can disrupt the entire alignment of the lower body, leading to issues that extend beyond the feet themselves.
Defining the Key Concepts
The term “flat feet,” medically known as pes planus, describes a condition where the foot’s medial arch is either collapsed or absent, causing the entire sole to make contact with the ground when standing. This physical characteristic can be present from birth or can develop later in life due to injury, age, or weakening tendons. Flat feet are defined by this static shape of the foot.
Pronation is the normal, dynamic motion of the foot that occurs during walking or running. This is a natural, necessary movement where the foot rolls slightly inward and the arch lowers to absorb the shock of impact and adapt to uneven surfaces. The foot then transitions to a more rigid structure for push-off.
When this inward rolling motion is too much, it is called overpronation. Overpronation means the foot rolls inward excessively and for too long during the gait cycle. The opposite motion, underpronation, or supination, is when the foot does not roll inward enough, causing the impact to be concentrated on the outer edge of the foot.
The Direct Answer: Flat Feet and Overpronation
Flat feet lead to the dynamic condition known as overpronation, which is an excessive inward rolling of the foot. When the medial arch is low or collapsed, the foot lacks the structural support needed to stabilize the heel and distribute pressure efficiently. This lack of arch integrity means the foot rolls inward past its neutral point during the weight-bearing phase of walking.
The biomechanical mechanism involves the arch collapse, which causes the heel bone to turn outward (valgus). This excessive inward tilt places strain on the ligaments and tendons that maintain the arch’s structure. Underpronation, in contrast, is associated with a high, rigid arch that does not adequately flatten for shock absorption.
The Impact of Excessive Pronation
Flat feet contribute to overpronation, and this excessive inward motion results in a chain of musculoskeletal issues affecting the entire lower extremity. The prolonged inward roll causes the lower leg and tibia to rotate internally. This rotation places compensatory strain on the knee, hip, and lower back joints, disrupting the body’s natural alignment.
Common symptoms arising from this misalignment include chronic heel pain, often due to plantar fasciitis. Overpronation also contributes to shin splints and Achilles tendonitis, due to the twisting stress placed on the tendon. The excessive inward force can also lead to the formation of bunions.
Managing Foot Biomechanics
The goal of managing flat feet and resulting overpronation is to mitigate excessive inward motion and restore functional foot mechanics. Custom orthotics and over-the-counter arch inserts are common strategies that provide support to the medial arch. These devices prevent the arch from collapsing excessively during the gait cycle, controlling overpronation.
Specific strengthening exercises are beneficial for improving the foot’s internal support system. Exercises targeting the intrinsic foot muscles and the tibialis posterior muscle are particularly helpful, as this muscle is a primary dynamic stabilizer of the arch. Actions like the “towel scrunch” or “tripod push” help build strength to resist collapse. Appropriately selected footwear, specifically motion control shoes, is designed to limit the degree of inward rolling.