Monday, May 14, 2012

Man or Woman, Trunk or Leg Fat - Adding a Full Body Strength Workout to Your Aerobics Will Burn the Fat Off!

Image 1: "Get up and move!"
Doing cardio is better than doing nothing. In the end, aerobic training does yet rarely produce those changes in body composition most "dieters" have in mind, when they embark on their daily jogging regimen and combine those with the latest and greatest diet fad they read about in magazines or on the Internet. If these people just added a few strength workouts to the equations, though, their bodies would begin to change; and what's even more exciting, according to a soon to be published study from the Pamukkale University in Denizli, Turkey, they will do that in the absence of any dietary changes and in exactly those problem areas, men and women usually hate the most about themselves: The trunk, for men, and the legs, for women (Sanal. 2012).

"Dieting"? Why, if working out alone elicits favorable changes in body composition?

The 92 healthy, yet sedentary and overweight men and women in the study were randomly assigned to either aerobics only (AE) or the combined aerobic + resistance exercise (ARE) regimen. Dropout rates (N=12 and N=11) were identical between the two 12-week interventions, which involved
  • AE: 3x per week 15 min @50-80% maximum heart rate in the 1st, 4x per week 20-30min in the 2nd and 5x per week 30-45min in the 3rd month aerobic training on the cycle ergometer
  • AER: Same as AE but additionally 2x per week full-body workouts with 2 min rest between sets and 3-6 sets of 10 repetitions @50% of their 1RM in the first 6 weeks, and 2-3 sets of 10 repetitions @75-80% of the 1RM during the second 6-week phase of the study
With the resistance protocol simply being added on top of the initially light aerobic workouts, it is quite clear that aside from the fundamental beneficial effects of strength training, the subjects in the AER group would capitalize on the overall higher workload, as well. After all, it is not very likely that the formerly sedentary study participants suddenly lead a more active life outside of their scientifically prescribed duties.
Figure 1: Relative changes in BMI, waist circumeference and hip circumference during the 12-week study period (calculated based on Sanal. 2012)
Against that background it may be initially counter-intuitive that the resistance aerobics + resistance training group did not lose more weight than their lazier peers (cf. figure 1), if you look at the data in figure 2, however, it becomes obvious why doing aerobics only really is not worth it, if your goal is to look better and get healthier, which both depend mainly on reducing your body fat levels, and not your body weight!
Figure 2: Relative changes in fat (FM) and fat free mass (FFM) in the course of the 12-week study period (DEXA data; calculated based on Sanal. 2012)
The dual-energy X-ray absorptiometry (DEXA; very precise method to measure the exact body composition) data confirms what every good trainer will be telling his clients, when they complain about "not losing weight" - the highly desirable changes in body composition are oftentimes not detectable with regular scales; and as this example shows, sometimes not even with my favorite tool, the measurement tape!

Men are different women, too, and strength training works for both!

And though this may sound like yet another prejudice, my personal experience tells me that women are usually much much more focused on the non-significant figures on the scale. Against that background I feel that the detailed analysis of sex difference with respect to the relative loss in body fat and increases in lean mass are of paramount importance, because they confirm: It does not matter if you are a man or a woman. If you want to look better, you got to lift weights!
Figure 3: Additional changes in body composition in aerobic + resistance training vs. aerobic only group (data calculated based on Sanal. 2012)
And while the added bonus of resistance training may be overall larger in men, than in women. It should be noted that the decrease in fat which was present in both groups, happened to be prominent in exactly those body parts which are usually held to contain sex-specific fat depots, i.e. the pot-bellied trunks of obese men and the "they are too fat for my skinny jeans" legs of chubby women.

Get going, don't stop eating, damnit!

Image 2: Some of you may remember my previous blogpost on the superior effect of HIIT vs. classic "cardio" on appetite and energy intake in obese boys. This is also why the SBSG Fat Loss Workout relies on both LISS and HIIT training.
Aside from the sex-specificity, this study provides an even more substantial argument in favor of exercise and against the "exercise just makes you hungry" hypothesis than the previously cited study (cf. "Dr. Oz Was Right, Taubes Wrong"). The question should thus no longer be "Shall I add exercise to my diet?", but rather which diet is most appropriate to propel the exercise-induced changes in body composition I am striving for.

In view of the fact that the study participants in this study, simply continued on their regular dietary regimen, you can only speculate how profound the changes would have been if the same 5x per week aerobic + 2x strength training regimen had been combined with a revised, not even necessarily energy deficient whole foods diet!?