I just finished reading a report of a research study from the December 2009 issue of PM&R: The journal of injury, function and rehabilitation.  The title of the report gave the conclusion of the study...Running in Shoes Stresses Hips, Knees and Ankles More Than Running Barefoot.  Now, you see why I had to read this one...

That is a pretty powerful statement and it seemed to me a little counter-intuitive.  The researchers observed the runners on a treadmill, both with shoes on and barefoot, with a motion analysis system.  They measured the joint torque at the hip, knee and ankle (joint torque is the amount of twisting about an axis that goes on at a joint.)

The researchers concluded from the joint torques that running with shoes on produced approximately 35% higher torques.  They explained that this is likely caused by an elevated keep and extra material in the medial arch.  

That's when my common sense approach kicked in!  I know when I run barefoot, I land differently, more gingerly and with more bend in my hip, knee and ankle.  Bending as you land is an eccentric movement and allows the body to absorb shock.  When I run in shoes, I know there is cushion and protection.  I am not worried about stepping on pebbles or absorbing shock.  I am more rigid in my landing when I wear shoes because I expect my expensive shoes to absorb shock, protect my foot and help support it.

With the extra bend in your joints, you can see that more of the force is in the up and down motion.  However, running forces are a forward and backward motion.  So, while research often leaves us with conclusions and 'take-aways,' it behooves us to look and listen critically at how the study was done and the inferences that are made from the results.  The reality for each of us is probably somewhere in the middle.  Since we are all very different, we need to take those results, apply them to our own circumstances and test the results on ourselves to make them relevant.

Be well read.  Ask lots of questions.  Have a healthy degree of skepticism.  Use common sense.