INVEST in a good pair of running shoes! Running any random shoe is fine until you get yourself a shoe made for running, then you will understand what I'm talking about. I have a pair of Nikes that I use only to lift in. Sometimes I decide to run for my cardio after lifting and I have on my "lifting" shoes and the next day my shins feel it. Running shoes DO MAKE A DIFFERENCE! I am very fond of BROOKS running shoes. They have many different styles to fit your needs (neutral, guidance, support, control, lightweight, trail etc.) I particularly need a shoe with more neutral support and the GHOST line have never let me down. They last too!!! I can't ever throw them out either when they have reached their limit. They become my lawn mowing shoes, grocery shopping, softball, outdoor shoes etc….. I am currently running in the Ghost 6's. I have loved the 6's so much that I needed a second pair. Each year I buy the newest make of Ghosts. I hope they continue to make them clear through infinity and beyond!!!