"Shugart: Good point. I'm going to throw out some very general questions now and let you guys duke it out. Here we go. What's better for the average guy wanting to be lean and muscular? HIIT (high intensity interval training) or long bouts of jogging at one pace (low-intensity)?
Staley: Clearly the former. There's really no debate on that. And you don't need a university degree or advanced physiology textbooks to understand why this is so: when you expose your body to repeated long-duration excursions, your body wants to weigh less in order to become more efficient at doing what you're asking it to do. And the easiest way for your body to weigh less is to catabolize muscle (which of course, weighs more than fat).
Shugart: What do you think, Coach Snippy?
Alessi: If they're a qualified HIIT trainee, that is, under the age of 35, without a pre-existing heart condition or family history and have at least six months prior training experience, then it becomes a simple energy game (calories in, calories out). For that, HIIT burns more calories in less time.
Shugart: HIIT or jogging, Thib?
Thibaudeau: Well, the only thing you have to do is compare the physique of a sprinter to that of a marathoner. Which one is leaner and more muscular? The sprinter of course! In fact, sprinters, as a group, have a better body than 95% of all the people spending hour after hour in the gym. This is all the more impressive considering that most sprinters will strength train three, maybe four times per week using only basic movements such as the bench press, squat, the Olympic lifts and hamstring work.
Of course, one could argue that the top sprinters are genetically gifted for leanness, strength and muscle. However, put the same guys on a hefty regimen of long distance running and chances are the quality of their physiques will vastly decrease.
This is not to say that low-intensity aerobic work is to be avoided. However, it shouldn't be abused. Let's face it, as T-men we like to shout high and loud that aerobic work isn't manly. But the fact is that aerobic work does offer several benefits, including the shift toward a better lipid profile, a lowered risk of cardiovascular diseases and hypertension, as well as fat loss. So aerobic work isn't the Devil; however, it's not the fastest route towards a muscular and lean physique.
In my opinion, long sprints, 200-400m (even 800m) with short rest intervals are best when it comes to losing fat while minimizing the potential for muscle loss. Most people wanting a great physique should engage in this type of activity. Furthermore, a recent study concluded that 400m running actually involves the aerobic energy system and lead to improvement in max VO2 similar to long, slow-pace aerobic work.
That being said, slow-pace aerobic work isn't to be discounted as it offers several health benefits. I know that health is always something that bores the athletes to no end, but good health is important: you can't improve if you're in the hospital can you?
Shugart: Good point. Lonnie?
Dr. Lowery: The way you posed that question makes for a difficult "right" answer. In short, either approach will work for an average guy wanting a little of each (some leanness and muscularity). Again, I prefer 100% specific, usually heavy, weight training sessions of 45 to 60 minutes for the muscle building, and then either 20 to 30 minutes of treadmill or 45 to 60 minutes of straight treadmill separated from the resistance exercise by at least four hours.
The treadmill session is scarcely even a workout, per se, for any intensity-crazed bodybuilder. Burning fat can be done at intensities that are low enough as to not interfere terribly with muscle recovery (e.g. a non-panting ten-second heart rate in the low 20's for a college-age male).
I respect the different approaches (HIIT vs. slow-and-steady) as equally valid but I'm old school in that I believe the crossover effect (burning fat at lower intensities and shifting to mostly muscle glycogen use at high intensities) can be manipulated to the bodybuilder's advantage. Slow-and-steady is a more direct and specific method for reducing subcutaneous body fat without interfering with muscle building efforts. "
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-Again, steady state cardio/aerobics, has it's place. It is pretty widely accepted in the strength and conditioning field that sprints, intervals, however you want to word it, are more effective at burning fat and maintaining muscle.