Back in my teens and 20's it felt like I could run forever, but my distance running never developed any speed. I often ran 7 miles at a time in training, and sometimes more than 10 miles a day. But always at roughly the pace I'll be using when I need a walker.I had a terrible gate running for distance. Had a good sprinters stride. I have a very good friend who looks like a gazelle and could run all day. He really helped me out. The farthest I have ever ran was a 10K and finished way back in the pack.