The kind of HIIT I'm doing is only 10-20s bursts, to stay within ATP-PCr energy metabolism (little lactic acid production). A short sprint followed by 2 minutes

The kind of HIIT I'm doing is only 10-20s bursts, to stay within ATP-PCr energy metabolism (little lactic acid production). A short sprint followed by 2 minutes rest. That's hard to achieve with a treadmill. https://en.wikipedia.org/wiki/Bioenergetic_systems#ATP%E2%80%93CP:_the_phosphagen_system https://en.wikipedia.org/wiki/Bioenergetic_systems#ATP%E2%80...