. >> kevin stone once a clinic in san francisco and is an expert in knee repair. he says padded running shoes encourage runners to land on the heel and roll forward. although the initial impact is padded but the force of the heel striking the pavement transmits more stress than a barefoot landing. >> it goes right through your knee and hip and back in a very bad way. as opposed to you landing on the ball of your foot or mid foot, at the they land in the mid foot or in the forefoot, muscles and tendons absorb the force and work like a ab absorber. >> recent studies including one at harvard generally support the safety and mechanics of barefoot running but they point out some of the risks. >> in the had a harvard study they found that barefoot runners that land on the heels create a collision force nearly three times their body weight, far more damaging if they wore shoes. diane phillips says her first run using the gloves were a learning experience. >> the next day, i couldn't walk. my calves were very tight. >> still her husband and her are converts and logged hun