The surface on which you walk and run CAN have an effect on how your body holds up to the exercise. To make your life as injury-free as possible, here's a chart which rates different surfaces on how accommodating they are to walking or running.
Surfaces are rated from ten (best) to one (awful):
Wood chips 9
Cinder track 7.5
In the article in which this chart appears, the writer states that we should all "get off the concrete. It's approximately ten times as hard as asphalt, and is easily the worst possible running surface."
Find some asphalt instead to walk on or visit your local high school track where the surface is more joint-friendly.
By Teresa K. Flatley
(This chart came from an article posted several years ago on the Cool Running website. For more information about running, visit www.coolrunning.com.