When doing HIIT, should one be aiming for maximal effort, or maximal effort that can be supported over the time period?

Question

I've been trying to get more exercise and, short attention span and lack of time that I generally have, I've been doing some HIIT workouts such as the 7-minute workout. I know that the "7-minute workout" is really intended to be repeated 2-3 times in a row. However, I also know that I can generally barely manage to get through the 7 minutes with my current level of effort, with my legs being rubbery enough at the end that it's a relief to end with planks.

So, my question is, if I'm aiming to do 3 sessions worth, should I push myself hard and resign myself to the fact that, at least at first, those second and third sessions will involve me slowing down as my endurance wears do, or should I be pacing myself so that I'm exhausted at the end of the 3, but I'm keeping a consistent level of effort?

Answer 1

You're basically describing threshold and interval type workouts, which are the staple of many movement type sports (Running, swimming, cycling, etc).

Threshold workouts are done at a slightly submaximal (or slower than a race pace) level, on short rest. These are designed to increase the amount of time you can spend at a certain level of exertion. Interval workouts are pretty much fullout, faster than your race pace level of exertion, with long rest between each interval.

One isn't really "better" than the other, each serves a purpose. You could alternate them to be able to build both systems to where you want. Ideally you'd always be playing "catch up", but getting better all the time.

One thing to think about, if you start getting to the point where you are tired on the maximal days, rather than slog it out at a slower pace, it might be better to just quit for the day. One of the cycling bibles (Training and Racing with a powermeter by Hunter Allen and Andrew Coggan, PhD) suggests that on interval type training days, if you are supposed to do X amount of work in Y time, but you only get to X-3 before you start failing to make your time, any more work won't be as productive as it might be and the extra rest would be more beneficial. Conversely, if you get to X and can still make it for X+z times before you fail to meet Y, keep on going. That way you don't overtire yourself on a "bad" day, and you take full advantage of your great days.