Various running surfaces can stress the body and feet in different ways, working different muscles or joints, requiring different positions and postures and causing different aches. The biomechanics of running changes depending on whether the surface is hard or soft, level or sloping. Runners therefore have to modify style and energy to match environment.
Many runners prefer natural atmospheres and take to the forest trails, grassy parks or dirt roads when running. Grass, dirt and sand provide uneven surfaces for runners, which allows the body to work the full range of muscles, joints and tendons for a more challenging and comprehensive workout. However, these uneven surfaces require extreme focus and awareness to prevent falls, ankle twists and injuries.
Natural surfaces are often softer and reduce the strain on joints, doctors claim.
Concrete and asphalt surfaces, especially when newly formed, offer runners a smooth, although hard surface. Old hard surfaces, however, can have cracks, holes and worn spots that offer as hazardous surprises. The hardness also tends to be rough on knees and feet.
Concrete is the hardest surface, and physicians at the Women’s Sports Medicine Center in New York City recommend avoiding concrete completely. If runners choose to jog on concrete, they should have shoes with the maximum level of cushioning and support in order to avoid landing with too much force. Sport medicine doctors warn that forceful landings on concrete can be strong enough to shatter blood cells and reduce the amount of oxygen that the blood can carry to organs. Furthermore, the hardness of the surface can make runners vulnerable to shin splints.
While asphalt is not as risky as concrete, it too can aggravate shins and cause stress fractures. Asphalt roads should be used with caution as they can meander and expose runners to dangerous turns and traffic, as well as toxic fumes from vehicles.
Tarmac and rubber are better choices than concrete and asphalt because they are less taxing to joints. Even though these are considered hard surfaces, doctors say runners instinctively adjust their leg stiffness to avoid harsh collisions with these surfaces.
Ultimately the type of surface that is right for you is a personal preference and depends on your level of comfort and personality. However, these medical reports may offer some persuasion.
An April 2012 report by the University of Hong Kong’s Department of Sports Science and Physical Education found that running on natural surfaces, particularly grass, resulted in less pressure on the plantar fascia, which is ligament on the underside of the foot that often gets inflamed and leads to a painful condition known as plantar fasciitis.
Grass and dirt trails get the highest endorsements from experts, provided runners choose ones without a lot of scattered rocks, debris and disruptive tree roots.
University of Michigan experiments found that runners had to flex their knees six degrees more when running on the treadmill compared to other surfaces; ankles had to be flexed more as well. In addition, treadmill runners ran with greater force and used unnatural body formation. These differences were attributed to the treadmill’s moving belt.
Researchers found that the heart rate gets more elevated and the level of fatigue is greater on the treadmill than on non-moving surfaces.
While many doctors advocate running on natural surfaces, one physiologist, Hirofumi Tanaka, from the University of Texas, disagrees. He cites the irregular surface of dirt and other soft surfaces as too hazardous and insists runners would fare better or smooth and hard surfaces.
Since most runners get bored sticking to one surface, there is no harm in varying surface as long as concrete is used rarely and running shoes are in good shape. Switching surfaces teaches the body to adapt and avoid injuries due to repetition.