Oh..ok, I've never seen that before. The tread sled isn't motorized, it isn't really a treadmill.
The tread sled is the thing in your clip? Yes I figured it wasnt and just relies on the athletes push power....
We can do the same with the treadmill, but mostly do overspeed training, flat or incline...
Seen some crazy improvements on 40 times and track athletes etc...