Though running regularly has many proven health benefits, it can actually increase the stress on joints on the legs. The December 2009 issue of PM&R: The Journal of Injury, Function and Rehabilitation, saw a study published where researchers compared the effects on knee, hip and ankle joint motions of running barefoot versus running in modern running shoes; it was noted that running shoes exerted more stress.
Sixty-eight healthy young adults, of which 37 were women, who run in the basic available running shoes were selected for the study. The participants did not have any history of musculoskeletal injury and ran atleast 15 miles every week. Running shoes with neutral classification and design characters was provided. Then, using a treadmill and motion analysis system, each participant was observed running barefoot and then with the shoes on. Observations were noted at each runner’s comfortable running pace after a warm-up period.
It was observed that joint torques increased at the hip, knee and ankle with running shoes compared to running barefoot. Very large disproportionate increases were observed in the hip internal rotation torque and in the knee flexion and knee varus torques. About 54 percent increase in the hip internal rotation torque, 36 percent increase in knee flexion torque, and 38 percent increase in knee varus torque were measured when running in running shoes compared with barefoot.
The findings clearly state that though the modern-day running shoes’ design gives good support and protection to the feet, they do have a negative effect I.e. increased stress on the three lower extremity joints.
This effect is most likely to be cause by an elevated heel and increased material under the medial arch – both characteristic of today’s running shoes.
Lead author D. Casey Kerrigan, MD, JKM Technologies LLC, Charlottesville, VA, and co-investigators state, also wrote that remarkably, the effect of running shoes on knee joint torques during running (36-38 percent increase) that the authors observed here is even greater than the effect that was reported earlier of high-heeled shoes during walking (20-26 percent increase). Considering that lower extremity joint loading is of a significantly greater magnitude during running than is experienced during walking, the current findings indeed represent substantial biomechanical changes.
He also concluded by mentioning that reducing joint torques with footwear completely to that of barefoot running, while providing meaningful footwear functions, especially compliance, should be the goal of new footwear designs.
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