I would like to initiate a discussion about peoples application and results with variant intensity interval training. I have read with great interest the different approaches, but one that constantly intrigues me is the camp that espouses a 75-80 or 85% “max” that includes a formula that uses someones age as a guideline. I can’t for the life of me find any merit in this formula as opposed to a performace based interval. The most recent that I have seen is a GXP, by master trainer, (self appointed or not I don’t know) Richard Winett. the Tabata material has been discussed, and variations or slight changes have been recommended, I believe varying for the by the book 20 second sprint and 10 second back off to a 15 second sprint with a 45 second back off.