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What are intervals? Why do them?

December 29, 2011

Most of my non-athlete friends have little sense of what my workouts are like. For example, my workout yesterday was 4 x (6 x 40″ hard, 30″ easy), 8′ rest on the erg. But what does that mean? To break that down, I started with an easy warmup. Then I did a 40 second all-out sprint, followed by 30 seconds of very easy rowing, followed by another 40 second sprint, and another 30 seconds of easy rowing, for a total of six sprints. After my sixth sprint, I took 8 minutes of rest. I rowed easy for some of this rest, but also just sat and recovered. After the eight minutes, I did another set of six sprints with 30 second rests between each. And then another eight minutes of rest. For a total of four sets of six sprints. (For those who don’t know, the erg is a rowing machine, a fantastic all body workout. Done right, it’s actually about 70% leg muscle, followed by core and back, and only a little arm. See for more information.)

“Interval training” is the general name for this sort of workout. Intervals might include multiple sets, like this workout, or might just include a single set (like the eight 500 meter sprints I did on Monday). Intervals always include short, maximum work efforts, and rest periods. So why train like this?

Increased maximum power: This sort of training lets me increase how much power I can output when I’m working at my cardio limits. In a long endurance race, like the Ironman, I can’t put maximum effort into every movement like in interval training. But the higher my maximum power output is, the more power I can put into my racing in an endurance event.

Increased cardio fitness and efficiency: This gives me a hard cardio workout, which is good for general cardio health. But more specifically, this workout develops my recovery ability and efficiency. The faster I can recover from max intensity efforts, the better I will do at the hard/easy rep cycle. This sort of workout encourages my body to improve its ability to recover quickly between reps. That recovery ability will help me in an endurance race, even if I’m not doing the same sort of all-out sprints. This also encourages my body to provide energy more efficiently, so that it doesn’t reach maximum quite as quickly.

Afterburn!: This is also great for just burning calories. This workout took 50 minutes (not counting warmup and cooldown). If I just got on the erg and rowed at a consistent, moderate intensity for 50 minutes, I would burn more calories during the workout. But the intervals also provide an after burn effect. My body keeps burning calories at a higher rate for 8 to 12 hours after this sort of intense work effort. But that after burn effect only comes with high intensity work, not with a long moderate effort.

325 days till Ironman Arizona.


From → erg, training

  1. Nice post. I am a huge fan of interval workouts for all the reasons you mentioned above… plus, I think the endorphins are better after tough intervals than after a longer, moderate paced workout.

  2. hey! do you row for real or do you just use the erg to train?

    • jbkosbie permalink

      Yeah, rowing is my sport even though I’m taking a break from on the water this year to do the Ironman. I rowed in undergrad (graduated 2006), took a couple years off, then got back into it with a local club team. And I have an erg at home — sometimes I think that’s a good thing, and sometimes I think it’s the worse idea in the world.

      • oh that’s awesome! i row in college too but got injured this year (my senior, ugh) and i’m out for the year 😦 where did you row? and i have an erg at home too…its a love hate thing as well haha

      • jbkosbie permalink

        I rowed at Brandeis, in Boston. I row with Lincoln Park Boat Club, in Chicago, now.

  3. oh no way thats awesome! when i was a freshman at lehigh, i rowed with a girl who rowed for lincoln park juniors….i row at fordham now and rowed at nyac a couple summers ago…i love how small the rowing world is haha

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