Monday, February 23, 2009
If you have ever read Popular Mechanics, or Discover, or any other remotely "sciencey" magazine, then you have probably come across the full paged ads for the Range of Motion (ROM) machine. I'll admit, I have wanted to try one for years! From what I can tell, the ROM has two major components - a rowing machine (the side of the machine with the seat) and a stepper (the portion behind the seat). The ROM ads are interesting for several reasons; the machine looks different from any piece of fitness equipment I have ever seen, the machine costs a lot of money (over $14,000 USD), and most importantly, they claim that you can get fit by exercising just 4 minutes a day! Forget about long hours in the gym, forget about active transportation, 4 minutes is all you need!
Ok, well, maybe not. From what I can tell, a typical workout on the ROM involves 4 minutes of exercising as hard as possible. The makers of the ROM claim that this can result not only in improved cardiovascular fitness, but also in reduced fat mass. As you might guess, I am pretty skeptical about a product that claims that you only need 4 minutes of high intensity exercise to stay fit. However, I was surprised to find that there is a reasonably large amount of evidence suggesting that high intensity training (typically done in several 20-30 second bouts of near-maximal cycling) has been reported to result in dramatic increases in cardiovascular fitness and even insulin sensitivity in lean, healthy individuals. There is some evidence that high intensity training may increase overall metabolism throughout a 24-hour period, but again this has never been demonstrated in obese individuals.
I did come across a very interesting paper from a recent issue of the journal Circuluation, which suggests that exercising at a very high intensity may be more beneficial than low intensity training in reducing both body fat and metabolic risk in individuals with the metabolic syndrome (a pre-cursor to both diabetes and heart disease). However, this study did 4 separate 4-minute intervals within a 40 minute workout - far more than the 4 minutes prescribed by the ROM. In fact, one of the key studies cited by the makers of the ROM as proving that this type of high intensity training increases metabolism included 30-minute aerobic sessions as well high intensity sessions taking much longer than 4 minutes (the warm-up alone took 5 minutes), making it difficult to extend these results to a single 4-minute continuous high-intensity burst on the ROM.
Despite these limitations, it is possible that high intensity training, and machines like the ROM, may be of benefit to some individuals. As I mentioned earlier, high intensity exercise has been linked to increased fitness and insulin sensitivity. In fact, high intensity training (in conjunction with longer aerobic training) has been used by elite athletes for decades precisely because it elicits adaptations that are not achieved through long aerobic sessions alone. Further, high intensity training may inhibit post-workout caloric intake (I can't stomach food for an hour or two following an intense workout), and it may even result in increased energy expenditure post workout. However, there are also risks - as Peter mentioned in an earlier post, jumping straight from a sedentary lifestyle into high intensity training may be a recipe for disaster. And to date, there is little evidence suggesting that performing such short bouts of exercise alone can reduce body fat levels in obese individuals. And let's not forget - it costs fourteen thousand dollars! Think of how many rowing/stepping machines you could buy with that amount of money. Or gym memberships. Or high quality food. Or personal trainers. In fact, you could finance most of a Kinesiology degree with that much money!
I am personally very interested in the way that exercise intensity influences health and fitness. In fact, I am currently overseeing a study which examines the influence of exercise intensity on health risk in overweight men. However, I am far from convinced that high intensity sprint training is the best way for most people to get fit. In the end, the greatest health benefit of the ROM may be due to its pricetag - if you spend $14,000 USD for a piece of exercise equipment, wouldn't you think twice before skipping your next workout?
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