This article was originally posted by Ryan at the original HillRunner.com Blogs.
HIIT is all the rage right now. Improve your aerobic fitness in 10 minutes or less of high intensity work by greater amounts than you can in 60 minutes of moderate aerobic running.
Sound like an infomercial to you? That’s because, in part, it is. However, there is some truth to what you hear that runners should keep in mind.
What is HIIT?
First, we should define what HIIT is so we know what we’re talking about.
A common definition I see offered is 4 repeats of 30 seconds with 4 minutes of recovery in between.
All definitions I’ve seen fit roughly this concept. A relatively small number (always less than 10 from what I’ve seen) of repeats of a short duration (I’ve seen anything from 8 seconds to 1 minute, usually 30 seconds or less) with varying recoveries.
What are the benefits of HIIT?
Claims are that these short but very intense workouts improve your "aerobic fitness" (usually measured as VO2max) even more than a 60 minute easy or moderate effort.
Note that VO2max is very important. It’s your measure of maximal oxygen utilization. Obviously, the more oxygen our bodies are able to utilize, the better off we are.
You’re running roughly at your VO2max when you run all out for 15 minutes so, for most runners, it’s between 2 mile and 5K race pace. VO2max is a limiting factor in running performance and is considered one of the critical physiological markers for runners in all long distance events.
What are the drawbacks of HIIT?
It sounds like we all should be doing HIIT, right? If it is the best route to improving our maximal oxygen utilization, doesn’t that sound like something we want to be doing? Well, maybe we should do it but not exclusively. There are two things to keep in mind.
First, HIIT training is good for VO2max but it may not be the best.
I’ve not yet seen a study comparing HIIT training to longer repeats of 2-5 minutes in trained athletes. Most people who know running will tell you that these longer repeats will be more effective in improving a well trained runner’s VO2max than repeats of less than 1 minute.
Second, VO2max isn’t everything for the distance runner.
Other factors such as lactate threshold, ability to burn fat effectively, even basic fatigue resistance of your muscles play a big role in endurance events.
But there are benefits so should I be doing some HIIT training?
Yes. Can you believe it? I’m saying you should be doing this hyped up fad workout!
But here’s the good news. You might already be doing it!
Do you do strides? If not, you should. If so, you’re already doing it. Most of us do strides ranging from 15 to 40 seconds so these fall roughly in line most with HIIT training suggestions.
Here’s some good news to go along with the potential VO2max benefits. Strides are also great for improving your form and running efficiency. That makes you a better runner, whether you’re focusing on the mile or the marathon.
So what’s the bottom line?
The bottom line is do some of these workouts. Whether you want to call them strides or HIIT training or just short repeats, I don’t care. Just make sure you’re getting the benefit of this useful workout.