I couldn't do it for a 400. Again I'm no spring chicken, I'm almost 50. I ran a 1:09 400m and I've run a 5:50 mile. Doing some workouts trying to run a faster 400 I've done strides where I hit low to mid 3 minute pace but I couldn't sustain that for a full lap. So I can hit 16 (maybe 17 or 18 mph) but certainly couldn't sustain it for more than the backstretch of a track. Strava doesn't have any step data that I can find. Fun thing about Strava is the segments and the 400m at the local track. For a while I was 4th fastest but every year a few more kids pick me off. Now I'm probably 13th or 14th.