That's flat-out flying. I'm
That's flat-out flying.
I'm guessing from your gender and age that you're probably pretty lightweight, which both decreases your damaging impact on each landing and makes it easier for you to go faster as you have less weight to carry. In order to run that fast, you're having to keep a mighty long stride, though. That usually means that your leading foot is landing way out in front of you and on your heel with your knee locked (or close to it). If that's the case, then 30 years from now when you're my age you'll have worn your hip and/or knee cartilege totally out on one or both legs.
I used to run shod at that pace up until a year ago, but I can't maintain it barefoot, as the braking friction on foot impact and the forefoot/toe friction on push-off/launch of each stride would shred the healthily-toughened skin on the soles of my feet. And again, the long-term effects of that long stride have left me with no cartilege in my right hip, which is what turned me toward BFR.
If you can maintain that speed healthily and nothing hurts, and you're doing so with good, healthy form (landing on your midfoot first, directly under your center of gravity), then keep flying like an eagle past all of us old worn-out guys. Check this site out for much more detail on good, healthy form that will keep you fit and let you stay that way for all of life.
Phil