Unstable Ground? How Surface Affects Your Walk
"Decoding the science of gait: Understanding how different surfaces change your walking style and what it means for your balance."
In South Korea, rising life expectancy and a focus on quality of life have boosted participation in physical activities like walking. People are increasingly choosing outdoor options, leading to the development of pedestrian paths with varied surfaces, from soft urethane to natural trails with uneven terrain.
The surfaces we walk on daily are rarely uniform, presenting challenges to our balance and stability. Changes in surface characteristics can disrupt our kinesthetic awareness – our sense of how our body is moving – and introduce mechanical perturbations. Our bodies compensate with biomechanical adjustments, like altering step length or width, to prevent falls.
While we intuitively adapt to different surfaces, understanding how these adjustments work can inform strategies for injury prevention and footwear design. This article dives into research quantifying how different surfaces – level, soft, and destabilizing – affect lower limb movement, center of mass, and center of pressure during walking.
Decoding the Impact: How Surfaces Change Your Gait
To understand how different surfaces affect our walking patterns, researchers in South Korea conducted a study analyzing the gait of 31 women as they walked across three different surfaces: a level surface (control), a soft urethane mat, and a destabilizing rock surface. Using motion capture technology, they measured various factors, including walking speed, stride length, foot angles, and center of mass (COM) movement.
- Walking Speed and Stride Length: Walking on the uneven rock surface resulted in a 23% slower walking speed and a 28% shorter stride length compared to the control and soft surfaces. This suggests a cautious approach to maintain stability.
- Center of Mass (COM): The height of the COM was lower on the uneven surface, potentially indicating a strategy to increase stability. The range of COM movement, particularly in the medial-lateral (side-to-side) direction, was also greater on the uneven surface, highlighting the increased effort required to maintain balance.
- Foot Progression Angle: On the uneven surface, the foot was more externally rotated (toes pointing outward) during the second double limb support phase – the brief period when both feet are on the ground. This suggests a change in ankle strategy to improve stability after the initial heel strike.
- Heel Contact Angle: The angle at which the heel strikes the ground was significantly lower on the uneven surface compared to the other two surfaces.
- Center of Pressure (COP): The COP trajectory, representing the path of pressure under the foot, was shorter in the anterior-posterior direction on the uneven surface. This indicates an effort to minimize movement and maintain a stable base of support.
Staying Steady: Implications and Applications
This research highlights the challenges our bodies face when navigating uneven terrain. By understanding how gait changes on different surfaces, we can develop strategies to minimize the risk of falls and injuries. For example, individuals with balance issues or those recovering from injuries may benefit from targeted exercises to improve ankle stability and coordination.
The findings also have implications for footwear design. Manufacturers should consider the impact of outsole design, lacing techniques, and ankle support features on stability, particularly for shoes intended for outdoor use. Features that reduce ankle rotation and provide better ground contact can enhance safety and comfort on uneven surfaces.
Ultimately, being mindful of the surfaces we walk on and adapting our gait accordingly can contribute to safer and more confident movement in our daily lives.