Wait for it. This is an unstructured workout. I KNOW. Ordinarily I’m all about structure and it is for this reason that you are unlikely to find me going for a run to ‘see what happens’. But removing some structure can do some great things for you. A few months ago I was doing intervals based on heart rate and because of that I had no idea what my pace was during the interval which is unusual for me. And because of that I ended up going way faster than I would have thought possible. Sometimes if we have an idea of a pace in our head that we are going to aim for, we just aren’t going to go faster than that. And if we happen to be slower than that for whatever reason, we tend to feel like we didn’t do well. But in fact, regardless of the pace if the effort was there the workout has given you what you need.
So the idea of this is to go out for an easy run (make sure you are warmed up first) and at varying points run 1:00 fast and then recover for a bit (but give yourself at least 2:00 before doing another one), and then go again until you’ve done eight intervals at a faster pace.
The beauty of this run is you can treat those fast intervals as REALLY fast, or you can treat them as just a bit faster than your easy pace – so it can be a pretty cruisey run or a really hard workout depending on what you feel like doing.