Are Sneakers More Dangerous Than Stilettos For Our Feet?

By Margarita Nahapetyan

Running shoes, decked out with most up-to-date cushioning, motion control and arch support technologies are not as beneficial to our feet and joints as we might think, reports a new study on joint health. In fact, running shoes can actually put more strain on our knees than a pair of high heels, and may be doing more harm to some of the joints than if we were running barefoot.

According to Dr. D. Casey Kerrigan, a professor of physical medicine and rehabilitation at the University of Virginia, running shoes are made with elevated heels, and though these heels are less extreme than those of high-heel shoes, Dr. Kerrigan was inspired to investigate and measure the damage sneakers can do to our joints.

The study enrolled 68 participants - 37 women and 31 men - who were asked to run recreationally, at least 15 miles (24 km) a week. All of them were equipped with markers on their knees, hips and ankles, as they had to run on a treadmill either barefoot or with a typical running shoe. As the subjects ran, cameras picked up these markers, allowing the investigators to see how the joints of the runners moved.

The specialized treadmill enabled the experts to analyze the impact placed on joints with every step made by the participants, and they were especially interested in measuring the torque (twisting of joints) around the knees, which is associated with osteoarthritis. Osteoarthritis is the breakdown of cartilage in the joints, which can result in bone rubbing on bone, causing strong pain.

The results of the experiment revealed that there was a 36 to 38 per cent increase in torque when the runners wore sneakers as opposed to running without any shoes. This number is usually much higher when compared to the torque increase when women wear stilettos, which typically increases between 20 per cent to 26 per cent. Disproportionately large increases were observed in specific areas: an average 54 per cent increase in the hip internal rotation torque, a 36 per cent increase in knee flexion torque, and a 38 per cent increase in knee varus torque were seen when the participants wore sneakers but not when they ran barefoot.

While exercise is without any doubt beneficial for overall health, running and walking put stresses on the joints that, in turn, may predispose people to developing osteoarthritis in those areas, said Dr. Kerrigan. Her advice to walkers and runners is to try minimizing forces on their joints in order to prevent this damage. And one again, although currently available running shoes are made with good support and protect the foot, the increased stress on the knee, hip, and ankle joints is a concern, as it is a risk factor for osteoarthritis. The study's authors assume that the increased stress is likely the result of an elevated heel and additional material under the medial arch, which are characteristic of modern running shoes.

The experts' recommendation for those who are overpronators is to buy running shoes with a Straight shape, for those who are underpronator - to go with a running shoe with a Curved shape, and finally, the recommendation for Normal/Neutral pronators would be to choose a running shoe with a Semi-Curved shape.

The findings were published in the December, 2009 issue of the PM&R, the journal of AmericanAcademy of Physical Medicine and Rehabilitation.