Your finest hour.

[communistworkethic]

Indeed dujon - a top marathon runner is going at 20kph (13mph), just try try running at that speed down the gym on a treadmill, it's a touch difficult for a few hundred yards let alone 2 hours.

Why is it so difficult on a treadmill to get up those speeds though?

For example, I often do 2km on the treadmill just a warmup before weights, and I do it in about 7mins30sec, which feels like a pretty fast pace to me, but on a track that's a crap time.

firstly, calibration, they're rarely going the pace you think. PLus the action of the belt and the difference in impact as you hit the thing is very different to running on a road, you should always have at least 1% incline on a treadmill to even some of that out.

Secondly, you just don't run as fast as you think you can.