Of course, there’s the other alternative.
HIIT (High-Intensity Interval Training) isn’t really in the same category as traditional “cardio.” If you do it right with extreme intensity, it’s very complimentary to hard resistance training.
While it can be highly effective for fat loss and improved muscularity, the devil is in the details. When deciding which version of cardio to use, the body’s natural physiological adaptations need to be taken into account.
Consider again how the “middle zone” cardio we talked about above (specifically in reference to our Bodybuilder B) is lousy for muscle gains. Adaptation is a response to stress, and biology will always seek efficiency and, consequently, minimization of stress. As such, the adaptation to this middle zone cardio is less muscle and more body fat.
In contrast, consider something like sprinting. Sprinting is the cardio version of maximal strength training. However, in this case we’re not moving weight, we’re moving our bodies. This essentially makes sprinting a “relative strength” activity, in that it’s the amount of force – in this case, propelling the body through linear space – we can exert in relation to our body size or weight.
Of course, we’re only as fast as we are strong, and the stronger we are, the faster we can be. And that strength, of course, comes from muscle. Even further though, sprinting is an expression of power output; it’s mass x acceleration. The more efficiently we can alter our physiology and replace fat with muscle, the greater the force output and thus, the faster our potential speed.
Consider then, if sprinting is the stress, and the imposed demands are maximal speed that’s compounded by mass relative to our ability to accelerate, what will make us more efficient/faster at sprinting? Getting stronger, of course, and sprinting itself can be anabolic.
As far as loss of fat, it’s the extraneous, unwanted, unneeded tissue that impedes acceleration. That’s why sprinters are lean. Sprinters have the lowest body-fat percentages relative to any other athlete. And I guarantee none of them train in a calorie deficit to look like that.
Their body composition and muscularity is the result of the natural biological adaptation that’s taken place in response to their imposed demand/stress, which, in this case, is maximal efficiency at maximal force output.
The body’s adaptation to middle ground cardiovascular exercise, however, is the opposite of weight training. In lifting weights, maximal strength often requires maximal bodyweight with higher body fat levels, but in cardio, maximal speed requires minimal bodyweight relative to the amount of muscle needed to reach top speed. In this case, however, minimal still equates to a lot of muscle, otherwise you won’t ever reach your speed potential.
Too much sprinting, however, can quickly burn you out, just as too much maximal lifting can. The dosage is hugely important.
These are the takeaway lessons:
- Lifters should augment resistance training with HIIT.
- Sprint-based cardio can equate to lower body fat levels.
- Don’t think of HIIT as calorie-burning cardio, but rather muscle-building cardio.
I’ve laid out two paths for you. The first – walking – will gradually get you cut without impeding further muscular gains, and the second – HIIT – will get you cut while building muscle. The choice is yours. Just avoid the middle ground.
Note: Alexander Cortes contributed to this article.