Monday, January 12, 2015

The Benefits Of High-Intensity Interval Training

The Real Reason To Do Interval Training

It gets cold where I live. But even when the forecast is for below-zero weather, I'd still rather go outside than run on a treadmill.
That should give you an idea of how much I dislike that particular piece of workout equipment. Nevertheless, when I decided to take up interval training, I found myself doing the hamster imitation because I find treadmills good for one thing: high-intensity interval training, or HIIT.

In an earlier article, I busted the myth that HIIT burns a lot more calories than regular aerobic exercise done at a steady pace. Ironically, while researching that column, I began doing HIIT for the first time in many years.

It wasn't to burn extra calories. The reason I was using HIIT was to train for a personal best in a 10K race. I wanted to run one in under 40 minutes and cross that off my fitness bucket list. Unfortunately, things didn’t quite work out that way.

Intervals can be run outside, of course. But one benefit of a treadmill is that it makes it easy to track the speed changes inherent in HIIT. It’s also not advisable to do speed drills on slippery surfaces, which is what Canadian winter is all about.

In my earlier article I showed how the vast majority of calories burned due to exercise come off during the actual workout and that the caloric "after-burn" due to HIIT is quite minimal. So if fat loss is your goal, then you want to maximize your aerobic "work."

This is interesting because my personal experience is that I can't do as much work engaging in HIIT compared with running at a steady pace.

If I'm not trying to do anything fancy, I can sustain a 7.5 mile per hour pace for about two hours and not be a bag of ass the next day. By comparison, when I do interval training at the oft-recommended 1-to-1-work-to-rest ratio, I can cycle back and forth between running at a 10 mph pace for one minute, followed by one minute at 5 mph, for an hour at most. That's followed by bitching and moaning.

Let's do the math. Running at 7.5 mph equals — duh — 7.5 miles run in an hour. And the above HIIT ratio involves 30 minutes at 10 mph and 30 minutes at 5 mph, so the distance covered works out as the same: 7.5 miles in an hour. Well, it’s actually a bit less than that because HIIT requires a slower speed warm-up and cool-down.

But the biggest problem is, after that hour, I’m totally done for. At a steady pace of 7.5 mph, I can keep going, but using HIIT, I’m in pain. This is from all that additional impact taking a toll, and also why most trainers recommend HIIT only be done twice a week.

So it’s not a miracle calorie burner, but how well does it work for improving speed?

To get the facts, I got in touch with James Fell, a senior lecturer who coordinates the Exercise Science Program at the University of Tasmania. And, yes, I did find him by Googling myself. Don't pretend like you've never done it.

Fell (the one in Tasmania) has authored a number of published studies on interval training and athletic performance. Via email, he explained that "high-intensity interval training does improve endurance performance. There are many studies to confirm this, ranging from the relatively untrained up to highly trained athletes." Fell also told me that the Scandinavians invented the concept in the 1930s with fartlek training but that today the approach is much more scientific.

Fell sent me graphs showing that intense exercise in short bursts followed by suitable recovery periods allows for greater total work to be completed compared with going at top speed until you're wiped. This larger volume of work allows for a greater training stimulus.

The effects of interval training on athletes, Fell reports, are "increases in the lactate threshold, maximal oxygen consumption and maximal aerobic speed or power. At the cellular level there are changes in mitochondrial number and function, enzyme activity, energy stores in the muscle cells" and a bunch of other stuff that all boils down to being able to kick a lot more butt on race day.

How much more? Fell co-authored a 2009 study in the International Journal of Sport Physiology and Performance that analyzed 10 well-trained male and female rowers. Half practiced HIIT for four weeks and half did traditional training. At the end of the experiment, the athletes in the HIIT group improved their 2,000-meter race time by 8.2 seconds, compared with a 2.3-second improvement for those in the control group. That extra 5.9-second improvement in a competitive race that lasts around seven minutes can be the difference between first place and the middle of the pack.

A year later, a research review in the Scandinavian Journal of Medicine and Science in Sports reported that incorporating HIIT into a training program could improve the exercise performance of well-trained adults by 2% to 4% in less than one month.

Interval training can also be good for people who don't engage in any anaerobic exercises that require short bursts of strength and power, such as weightlifting. I spend a lot of time lifting weights, so I'm already getting plenty of anaerobic exercise, but if all you ever do is aerobic activity, then HIIT would allow you to train the larger "fast-twitch" muscle fibers that can increase muscle mass and improve your physique.

If you need convincing, remember that your typical sprinter looks like the Old Spice guy, whereas most marathoners resemble Sheldon from The Big Bang Theory. It's important to note, however, that HIIT won't build as much muscle as intense weightlifting.

If you decide to give it a try, keep in mind that the National Strength and Conditioning Association (to which I belong) says that interval training is not for the out-of-shape and should be used sparingly because of its punishing intensity.

I can vouch for that. But you do get used to it.

The Benefits Of High-Intensity Interval Training



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