high intensity interval training

So one of the thing Crossfit really emphasizes is high intensity interval training. For example one of their classic workouts is the “Tabata protocol“: eight rounds of 20 seconds of intense exercise followed by 10 seconds of rest. Typically it is done with such things as situps, squats, pushups and pullups. It is only a four-minute workout (well, 3:50), but the key is to do it all out and really wipe yourself out by the end. It takes its name from a study by Japanese scientist Dr. Izumi Tabata, who found that intervals of exactly that type on a spinning bike (five days a week for six weeks) produced better training than constant-state training for an hour over the same timeframe.

That’s worth repeating: an intense four-minute workout was proven better than a moderate hour-long workout.

Anyway, as a runner, intervals are nothing new. But I was also taught about tempo runs, intense ~30 minute runs that are also supposed to be good training.

I did a little research on the web. Here‘s one meta-study that compared high-intensity various training schedules. Like is a hard 1×20 min. run better than 5×3 min.? Interval training at 2-10 minutes seemed to be better than training at shorter intervals, and much better than training at longer intervals. Here’s another study that seemed to indicate that a 5×2 min. hard runs, interspersed with equal periods of light jogging, were better than 10×1 min. workouts or a 1×20 min. hard run.

So maybe tempo runs are just hocus and we should all be doing intervals instead for our hard runs? I know when I’ve done tempo runs by myself — it is just plain hard to keep that intensity, concentration and focus for a full 30 minutes. Any kind of distraction — say, rounding a corner — usually makes me break my rhythm and drop my heart rate a little bit. (From what I’ve read, tempo runs are supposed to be at 85% of max heart rate, hard for me to maintain without someone else pushing me). Anyway, I think I’m going to drop “tempo runs” and just do intervals and races.