In the last two months, I’ve added two workouts to my menu. Both are well suited to the winter weather and the extensive travel I’ve been doing.
First, I’ve been doing a 20 minute body-weight circuit in which I do 10 reps consisting of 30 seconds each of squats, pushups, lunges and jumping jacks. Each circuit then is 2 minutes. It’s a continuous, high intensity effort that pushes both strength and cardiovascular fitness.
Second, I’ve been doing 20 minutes of 8 second all out sprint with 12 seconds of rest on my indoor bicycle trainer. Using a high level of resistance, it’s similar in effect, but cycling specific.
I’m convinced, based on the work specificity that these efforts will push VO2 max and power. I can’t help but wonder how effective endurance builders they will be based on the specificity principle. While with warm up and cool down, a high intensity workout lasts nearly an hour.
As adaptation to a 20 minute workout is achieved, the question becomes whether to push intensity within the 20 minutes or to keep intensity constant and increase duration.
20 minutes is a convenient and achievable duration for high intensity workouts. By using intervals that allow rest (either as a circuit that rotates muscles or as intermittent sprints) sustaining a high level of cardiovascular effort can be combined with high power output. But I think that continuous power output, what Joe Friel calls “muscular endurance” is different from the VO2 max related abilities to clear lactate during short, high intensity efforts.
Yesterday I tried adding another workout on the bicycle trainer- a steady effort for 20 minutes at highest sustainable heart rate, about 90% of my 12 minute maximum effort on the Cooper Test. It felt about as hard as the 8 second sprint workout. I’m going to try to extend that effort from 20 out to 40 minutes for a full 60 minute workout.