I hate them. I love them. But they work.

A Baseline Workout is an effort that is repeated regularly during a training cycle and for which thegoal is to match or improve upon all past performances [ these were described in detail in the first guide, so if you want all the nitty gritty, please refer to that, as this page is just a summary ]. Baseline workouts are CRITICAL for both assessing your fitness gains and ensuring that you have benchmarks that push at least some of your sessions to near max-effort levels.

When I'm really getting after it and trying to maximize improvement in a given discipline (such as running), at least 2/3 of my weekly efforts are repeated baseline workouts. A steady diet of Baseline workouts, when extended over a period of weeks and months, are incredibly demanding but also incredibly effective as they force you to work nearer and nearer your actual potential, maximizing the 'return on investment' of your effort. This is the hallmark of HIIT, but again, true HIIT is not easy nor is it necessarily even accessible for any given workout or even at all without the use of baseline workouts and objective feedback (see one hour series guide #1).

Suffice to say, your running program will use a number of Baseline workout, so get ready!