20 mph is fast now? That is a completely pedestrian speed. Fast humans can run in the upper 20s and dogs can run in the mid 40s.
Huh? You're clearly not a runner. Upper 20's is bullexcrement.
Really fast runners out on a MUP might be managing 5 or 6 minutes/mile, which is 10-12mph. Current world record for the mile is 3:43.13, or 16.14mph. Current 400 meter world record is 43.18 seconds, or 20.7mph. 100 meter world record is 9.58 seconds, or 23.5mph.
If you know someone managing upper 20's they need to be heading to Brazil this summer.