It might be those specific workouts. I could do things like Warlow or Three Sisters where the interval was 9 minutes and where the ‘over’ was one minute. But if I tried the 12-minute variety, I’d get smoked. The solution? Substitute the 9-minute variety for the workouts you are having trouble with. Then move to the 12-minute variety once the legs and heart are up to it.
Remember: the end of any given over/under set is going to hurt. We only come back for another because of the generous rest interval…
I’m working my way up to Carson these days and am looking forward to revisiting these over/unders in a month or so.