I know what HR I need to hit for VO2 (sadly do not yet own a power meter). My problem is in finding the right length of interval, and recovery. I've gotten two different answers so far: one, a ~5 min interval with equal recovery; a 1 min interval with equal recovery.

This is the first time for me to do these intervals too -- bear that in mind. I've done plenty of LT 2x20's etc. and races, group rides, but never have tried VO2 before.

I guess another question would be when to start? I have my first race in three weeks; however, I don't want to peak until early May (then again in early August). Is it too soon to start the VO2 training?

Thanks for the help.