I just had a quick google as I fancy something different to my 20 minute run post boxing tomorrow.
The video tutorial recommended a 2:1 ratio. His example was 1 minute skipping followed by 30 seconds rest for a maximum of 20 minutes.
I thought it should have been something really intense like beasting it on the rower or a flat out sprint and a ration of something like 20 seconds effort and 40/60 seconds rest. However this is just what I assumed. He also said HIIT can be performed with jumping jacks, body-builders, rock climbers and high step ups.
Maybe Wanton could clarify for us as I'm guessing he's a PT.