A close look at P90X

I didn't actually ever plan to do a close look at for an exercise program. Mostly because there's really no scientific studies done on specific programs – nor do they usually really need it. Getting up and moving is the goal and unless the program fails to elevate heart rate, as “Wii Fit” did, it's probably an okay exercise program.

But P90X was studied by the American Counsel on Exercise in conjunction with the University of Wisconsin. ACE selected some of the P90X program videos to determine the energy cost and exercise intensity they provided.

Muscle confusion was the part I thought was just made up; a term to make something sell better. It didn't make the P90X program, or any other program using these terms, less viable as exercise programs, but I didn't buy the hype. It turned out what they call muscle confusion is called 'daily undulating periodization' scientifically which is the idea that changing up workouts regularly gives the body no time to adapt and become efficient at the exercise. No body efficiency or muscle memory? No plateaus. The body is constantly burning fat and building muscle just as efficiently as the first day you started.

So I'll just sit here with egg on my face because I had no idea this was a scientifically proven phenomenon! Also, bravo to whoever came up with the term 'muscle confusion'. It's much more layman friendly than 'daily undulating periodization'.

But how did the videos fare when tested in a lab?

“Plyometrics workout proved to be the biggest calorie burner, while the Chest, Shoulders & Triceps routine burned the fewest number of calories.” This is not really surprising seeing as the Plyo exercise is a heavy duty aerobic workout while the Chest, Shoulders and Triceps workout is a weight lifting circuit. That it got the study participants' heart rates up into their target heart rate zone (about 129) by itself is pretty impressive.

“Researchers noted that given these results, the P90X workouts that were tested (and, therefore, most likely all of the P90X workouts) meet or exceed established fitness industry standards for losing weight and improving cardiorespiratory fitness.”

And how about the calorie burn?

Though the P90X Web site does not promise specific calorie-burn numbers, postings on online message boards and Web sites suggest that P90X can burn over 1,000 calories per hour. Porcari warns would-be exercisers to “take those calorie-burn claims with a grain of salt,” he says. “When you look at the average caloric expenditure for P90X, it’s actually very comparable to jogging.”

Beachbody actually does advise a calorie burn range in the P90X Extreme HomeFitness Nutritional Plan book that comes with the P90X kit. It's a bit of a missed opportunity that they went to the website, and the very inaccurate forums to take numbers from users instead of Beachbody itself. The supplemental nutrition books says, “we have calculated... 600 calories per day for the P90X program.”

And considering how variable the calories burned during a jog are – based on how fast you were going – it's not really saying much to say it's comparable to a jog. Is that a slow jog? Fast jog? Extra fast jog just short of a run?

It would have been nice to see if they agreed with the 600 calorie burn the Nutritional Plan book stated.