I'm 45 y/o and weigh ~ 20 pounds more than I'd like. I have scoliosis and a slight leg length discrepancy that is helped w/an orthotic in one sneak. I've been concerned about the impact of jogging on my spine and my knees, so I've been using the treadmill. I've found the C25K program to be a really excellent blend of easing me into jogging and challenging me to improve. The program really does go slowly enough that I haven't had any serious joint issues at all. And I'm quite happy to progress slowly! I call it wogginhg (walk/jog). I hope to eventually try jogging outdoors, but it will really depend on how my spine does. So far, so good. I recommend the C25K to anyone who has an interest in jogging!