I run 3 miles on my short days and 7 miles on my long days. I climb stairs or do elliptical as a break from running, and I do some weights for my knees to add strength. I mostly run on treadmill at the gym to reduce the stress on my knees and legs, and watch TV to keep from getting bored as I run. Treadmills are bouncy, so they're considered the softest possible surface. I would happily switch to a dirt or gravel path (the next softest surface) and run outdoors, but there's nothing nearby. I don't do asphalt or concrete if I can avoid them--too hard on my knees as I get older.
@Shin splints: I used to have a semi-permanent case of those. But I eventually got rid of them many years ago by paying attention to my equipment and technique:
--Shoes have different levels of cushioning. Get the ones with the most bounce and cushioning; and get 2 pairs and alternate between them if you run a lot so that the shoes have time to dry out and recover between runs--they'll last longer. Throw out shoes when they start to lose their bounce.
--Do a lot of vigorous calf and knee stretches to loosen up before and after the run.
--Steer toward running on the softest surfaces possible. Never run on sidewalks--concrete is the worst.
--As you start running a lot, lean a little futher back and lengthen your stride so that you land on your heel (rather than landing flat on your foot or on the ball of your foot), and then roll forward and step off the ball of your foot. It leads to a lower, faster, smoother, rolling gait with less shocks and bouncing around.
--Of these measures, the stretches beforehand and lengthening my stride seemed to do the most to get rid of the shin splints. The rest are just about reducing the general level of impact for the entire leg.
I'm suddenly seeing a lot of people doing wind sprints on the treadmills at the gym lately. I don't know if that's a new thing, or if it's just a seasonal crowd coming in to get in better shape for the coming good weather. I don't know whether sprints would be good or bad for shin splints. I've used sprinting to work on a longer stride. The longer stride works better at faster running speeds; if you try to do a slow jog with a long stride, you get kind of a weird loping stride.
