Foot movement during walking and running involves complex biomechanics, often using terms like “supination” and “underpronation.” These terms can be confusing and are sometimes used interchangeably. This article clarifies their specific meanings and relationship within human movement.
Understanding Supination
Supination refers to an outward rolling motion of a body part, specifically applying to the foot. In the foot, supination involves outward rotation, shifting weight predominantly to the outer edge. This action elevates the arch, creating a more rigid structure. This motion is a natural component of the gait cycle, occurring as the foot prepares to push off the ground and helping create a stable lever for propulsion and efficient forward movement. While a degree of supination is normal, issues can arise if this motion becomes excessive or occurs at inappropriate times.
Understanding Underpronation
Underpronation describes a specific pattern of foot mechanics during walking or running. It is characterized by insufficient or absent inward rolling of the foot, known as pronation, during the gait cycle. During normal gait, pronation is the natural inward roll that helps absorb shock and distribute impact evenly across the foot. When underpronation occurs, the foot remains in a relatively rigid, supinated position for too long, or rolls excessively outward. This means the foot does not adequately flatten or adapt to the ground, leading to reduced shock absorption, and impact forces are then transmitted more directly up the leg, potentially affecting the ankles, knees, hips, and lower back.
The Relationship Between Supination and Underpronation
While often used synonymously, supination and underpronation represent distinct but related concepts in foot mechanics. Supination is a specific motion of the foot, involving an outward roll and elevation of the arch. It is a natural and essential part of the foot’s function during the gait cycle, particularly as the foot transitions from absorbing impact to propelling the body forward. Underpronation, conversely, is a descriptive term for a gait pattern where the foot either exhibits too much supination or insufficient pronation. It signifies that the foot stays excessively in a supinated state, or fails to pronate adequately, throughout phases of walking or running where pronation would normally occur for shock absorption.
Therefore, underpronation is effectively the result of the foot remaining in a supinated position for too long, or to an excessive degree, during the weight-bearing phases of movement. Consider supination as a verb describing an action, and underpronation as a characteristic or state of gait. A foot that underpronates does so because it performs the supination motion excessively or fails to perform the necessary pronation. This distinction highlights that while supination is a natural movement, underpronation is a functional pattern that can lead to reduced shock absorption and uneven distribution of forces across the foot and lower limb.
Identifying Your Foot’s Movement and Its Significance
Understanding your foot’s movement pattern, such as whether you underpronate, can be helpful for selecting appropriate footwear. One common method to get an idea of your foot arch type is the “wet test.” Wet your foot and step onto paper or cardboard, then observe the footprint. If your footprint shows very little contact in the middle, with only the heel and ball of your foot visible, this may suggest a high arch, often associated with underpronation.
Another indicator is examining wear patterns on old shoes. If you underpronate, you will typically notice excessive wear along the outer edge of the sole, particularly from the heel towards the little toe area. Placing your shoes on a flat surface might also reveal an outward tilt. While these methods offer general insights, they are not diagnostic tools. Recognizing these patterns can help in choosing footwear with adequate cushioning for comfort and support during daily activities and exercise.