The news media is picking up the results of a new study showing that running shoes are worse on your knees than running barefoot. The stories also mention that even high-heeled shoes are better (though, in all fairness, this is a bit of comparing apples to oranges).
The Daily Telegraph also has a story. In this article is it made clear that the study showed that running in running shoes is worse than walking in high heels.
The lead author of the study, Dr. D. Casey Kerrigan, has been doing these sorts of studies for a long time. “Knee osteoarthritis and high-heeled shoes” and “Women’s shoes and knee osteoarthritis” are the two studies she was involved with that showed the effect of high heels on walking.
The new study, The Effect of Running Shoes on Lower Extremity Joint Torques”, shows that knee varus torques and knee flexion torques are about 40% higher in running shoes than barefoot, and hip internal (or medial) rotation torques are about 50% higher. It was published in the journal of The American Academy of Physical Medicine and Rehabilitation: PM&R, Volume 1, Issue 12, Pages 1058-1063 (December 2009).
The knee varus torque refers to the left/right forces on the knee as you run or walk. The knee flexion torque refers to the front back motion. These sorts of stresses on the knee bones and cartilage are implicated in osteoarthritis of the knee. The hip medial rotation refers to rotation of the thigh about the hip.
The study itself ends with a rather odd sentence:
The use of athletic footwear in running as a means to protect the foot from acute injury and the potentially debilitating effect of switching to barefoot running on foot health excludes such an alternative.
Huh? This statement appears to be without foundation, and just perpetuates the usual fears about going barefoot. I’m not even sure what they mean by “acute injury”, but I can guess that they mean something like stepping on glass. That is extremely rare, and even more rarely “acute”. In fact, most of the “acute” foot injuries are bloody blisters, caused by shoes, not going barefoot. It is also not clear what they are thinking about barefoot running having a “potentially debilitating effect” on “foot health”. What is telling, though, is that this statement does not have any citations associated with it (as they did with their other remarks that actually were based upon other studies).
Oh, and the recommendation of the study? Come up with new footwear designs. That is, after all, what Kerrigan’s company, JKM Technologies, does. I’m sure that didn’t affect the results of the study, but it does show a certain blindness towards a possibly more effective (and cheaper) solution: running barefoot.