|This article is not supposed to encourage the use of exercise as a means to eat more junk. After all a psychotherapeutic / psychiatric ward is the only place this form of exercise addiction is going to get you.|
Yet even if you don't train to burn calories, it can be very useful in all these contexts to have at least an estimate of how much energy you're spending during the workouts. What for? Well, to know roughly how much more you'd had to eat to stay in an energy and how much more would be too much so that fat gain would be the inevitable consequence.
Speaking of energy balance(s), you should also be aware that your body will adapt to chronically reduced energy intakes. In other words: If you have been dieting for say 8 weeks, it is not unlikely that you are spending slightly, but statistically significantly less energy for the same workout (15 reps 70% of 15 RM, 2 s:1 s cadence; 45 s per exercise; only 15 s of "rest" = moving to the next exercise | running during the CE was performed at 70% | the total duration of one lap of the circuit was 7 min and 45 s, for the total time the subjects actually worked out (not how long they were in the gym, it was 3x 7:45 = 23 min and 15 s | see Figure 1).
|Figure 1: Overview of the standardized circuit resistance training protocols in Benito, et al. 2016.|
- the combined resistance + endurance training regimen (CE, exercises see Figure 1, bottom), with 13kcal per minute (8.4 kcal/min in women), was by far the most energetically demanding (is also had the highest fat/glucose oxidation ratio, meaning more workout fuel came from fat - not necessarily body fat, though - in CE) and that
- free weight (FW) training, with 10.4kcal/minute (6.4 kcal/min in women), was more demanding than machine-based circuit training (CM), with only 8.9 kcal/minute (5.4 kcal/min in women).
I guess this won't really get you excited... well, rightly so. After all, many of you may not be happy with health and weight loss as their primary goals and will thus pass on combined training, anyway. And still, there is something in this study that is actually quite intriguing - even for those who don't do cardio because they're afraid it will hurt their gains (which is bogus, if it's not done excessively) - and this "something" is the fact that the increased energy expenditure in the combined training group (CE) did not go hand in hand with increased ratings of perceived and objective markers of exertion.
On the contrary combining weights + cardio (CE), produced significantly (both statistically, as well as practically) lower lactate concentrations and significant reductions in the subjects' subjective rating of their individually perceived exertion (RPE, Figure 3). Or, as the authors' have it: "[A] combination of resistance exercises and running produces VO2 above 50% VO2max, the highest EE, and the lowest perception of effort" (Benito. 2016). This is interesting and in a way counter-intuitive as one may expect that the most energetically demanding workout would leave the subjects with the highest perceived and objective markers of exertion.
- Benito, Pedro J., et al. "Cardiovascular Fitness and Energy Expenditure Response during a Combined Aerobic and Circuit Weight Training Protocol." PLOS ONE 11.11 (2016): e0164349.