The idea that walking without shoes can permanently increase the size of an adult’s foot is a common question. Many wonder if the foot’s structure, composed of 26 bones, can lengthen or widen simply by changing footwear habits. This perception often arises when people transition away from restrictive modern shoes to a barefoot lifestyle. Understanding the underlying anatomy and physiology of foot growth is necessary to provide a clear answer.
Does Barefoot Walking Increase Foot Size
Walking barefoot does not increase the actual skeletal size of a fully developed adult foot. True bone growth is determined by growth plates, or epiphyseal plates, located near the ends of the long bones. These plates are composed of cartilage that multiplies and calcifies, lengthening the bone during childhood and adolescence.
Once a person reaches skeletal maturity, typically in the mid-to-late teens, these growth plates fuse completely, and the bones can no longer lengthen. Since the adult foot’s bone structure is fixed, no amount of walking can induce further growth or add new bony mass. The confusion about size often stems from temporary functional changes or the perception of greater width.
Defining Factors of Adult Foot Size
The primary determinant of foot size and shape is genetics, which establishes the blueprint for the skeletal structure, including bone length and overall foot proportions. Children inherit traits that dictate their maximum foot length and width before the growth plates close. This genetic influence is why foot size is often correlated with height and ancestry.
While skeletal growth ceases in adulthood, the size of the foot can still change due to non-skeletal factors. Significant changes in body mass, such as substantial weight gain, place increased pressure on the foot structure. This chronic pressure can cause the ligaments and tendons to stretch, resulting in a flattening of the arch and a measurable increase in foot length and width.
Pregnancy is another factor that can cause a permanent, non-skeletal increase in foot size. Hormonal changes, specifically the release of relaxin, cause ligaments throughout the body to become lax. This laxity, combined with added body weight, contributes to the arch falling and the foot splaying out, often resulting in a lasting increase of up to one full shoe size. These instances represent a change in the functional shape of the foot, not a renewal of bone growth.
Functional Adaptations of the Foot
Toe Splay and Width
The perception that feet get bigger when walking barefoot is largely due to the unconstricted nature of the foot’s soft tissues. Traditional, narrow-toed shoes compress the forefoot and toes over time, forcing a narrower shape. When transitioning to a barefoot lifestyle, the toes are allowed to spread out to their natural, anatomical position, a process known as toe splay. This natural spreading results in a measurable increase in foot width, particularly across the ball of the foot. Studies show that barefoot individuals consistently possess wider feet, which is a functional adaptation that enhances stability.
Muscle Strengthening
Barefoot walking also activates and strengthens the intrinsic foot muscles, which are the small muscles located entirely within the foot, such as the abductor hallucis. Without the passive support of a shoe, these muscles must work harder to stabilize the arch and control foot movement, similar to a workout. Research has shown that walking in minimalist footwear, which mimics the barefoot condition, can increase the size and strength of these intrinsic foot muscles. This localized muscle hypertrophy, or increase in muscle cross-sectional area, contributes to a more robust, wider-looking foot without adding to the length of the bones.