Interval Training Research
Here’s something off the beaten track that I found while looking at some exercise physiology journal articles on interval training. There’s apparently been some very convincing and very specific research into optimal interval training methods in the last five years, and the results are surprising. There was an article recently published in the Journal of Applied Physiology titled “Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans” that was particularly shocking, at least to me.
The tested workout schedule in the study consisted of 4-7 thirty second intervals of maximum effort with four minutes of rest in-between each repetition. Every other day. For two weeks. That’s only about fifteen minutes of exercise—in total, over a two-week period.
I know, if you’ve done interval training before, you’re laughing. That seems like such an incredibly small amount of work, with such a huge rest interval, that it seems like a waste of time. Particularly when you consider that was the entire workout. The volunteers for this weren’t hardcore athletes, but they were “recreationally active” (worked out two to three times a week).
The exercise performed was on a stationary bike against load. Remember, absolutely maximum effort for thirty seconds with four minutes rest between repetitions.
After two weeks, endurance time to fatigue doubled (cycling at 80% V02 max).
What the? How did that happen?
Here’s their best guess:
The maximal activity of citrate synthase increased by 38% after training. Resting muscle glycogen concentration increased by 26% after training… We can only speculate on potential mechanisms responsible for the dramatic improvement in cycle endurance capacity, but it is plausible that a training-induced increase in mitochondrial potential, as measured by citrate synthase maximal activity, improved respiratory control sensitivity during exercise.
Crazy stuff. I used to do interval workouts on a track (when I was much younger) and felt like I wasn’t workout out hard enough if I didn’t need to puke at some point. Now I find out I could have been running for thirty freaking seconds at a time with FOUR-MINUTE rest intervals.
Damn it, science. Fifteen years too late for me.
It would be tough to do this in a running program (hello, blown hammy), but I think cycling and swimming would probably work fine. I haven’t actually incorporated it into my own swimming program (I think swimming that little for two weeks would drive me crazy), but it definitely has me thinking, and I’ve incorporated some very fast, short intervals into my workouts, and I’m swimming faster as a result.