If you’ve ever spoken to a bodybuilder, they’ll tell you just how physically taxing posing at a competition can be. All of the personal theatrics and hot lights aside, the effort required to hop on stage, repeatedly flex your muscles in front of the judges by locking them rigidly in place while shifting them around so that they can be admired from all angles is exhausting, especially if you’re called back for additional rounds of flexing.
In that context, it’s more than fair to refer to flexing as a legitimate workout considering the number of boxes it checks — it’s a full-body exercise, the muscles are reasonably challenged and there’s plenty of blood sent coursing through the anatomy.
Can I, too, build muscles merely by flexing them?
Sort of. But on a 1-to-10 muscle-building efficiency scale, flexing ranks very close to the bottom.
Interestingly, despite everything I said above, the best evidence of flexing as a muscle-builder are seen in untrained individuals. Case in point: In a 2013 study, individuals who had no prior involvement in any sort of weight-training programs were subjected to three flexing-based workouts per week for 12 weeks. On average, they experienced modest gains in muscle size and thickness compared with the control group, which performed no form of resistance training at all.
But in all reality, this isn’t actually that surprising. What the study fails to provide is a comparison between the training results of individuals who simply flexed their muscles against the results of people who trained diligently in the weight room over the course of the same three months. Ordinarily, people who have never trained with weights or other methods of resistance before will accumulate new muscle at a respectable rate of one pound per month once they commence such training practices.
Therefore, it’s highly likely that noticeable muscle increases would have been more pronounced following prescribed resistance training, and also accompanied by improved output on most strength measurements as well.
Why doesn’t flexing work to build muscle as effectively as resistance exercises?
I know that it would be a dream scenario to build muscle just by participating in a self-reverential gun show every afternoon in the mirror. Yet, the problem here is twofold.
First, even if you were attempting a Charles Atlas’ Dynamic Tension form of exercise, it’s impossible to self-apply the external tension necessary to create significant hypertrophy in your muscles that can approach that of other forms of resistance training. And that’s a best-case scenario in which you could forcibly work one muscle against another to create the resistance, like using your left hand to forcibly restrain your right hand as you attempt to raise it into a bicep contraction. The problem is, very few areas of the body can be similarly restrained in such a way.
Moreover, the act of flexing usually causes the inferior equivalent of an isometric hold. As with all isometric exercises, the contraction of the muscle in a single place means that strength is only being gained in that position. So what we’re describing is essentially the difference between a plank and a crunch — the plank builds strength in the abdominals and other muscles that are responsible for locking the body into place, but only in the position of flexion. Meanwhile, the crunch is building strength in the abdominals throughout their full range of motion.
Keep in mind, too, that meaningful muscle is built as a result of being repaired following a workout, not during a workout, and serious growth requires the constant micro tearing and rebuilding of muscle fibers as they’re being forced to adapt to increasingly heavier training loads.
So what you’re saying is, flexing really does nothing for me?
Not consistently. You’re certainly not going to turn into Ronnie Coleman, Phil Heath or Mamdouh Elssbiay just by assuming enough double-bicep poses in the mirror. If you could, none of these Mr. Olympia winners would expend all of the grueling effort to sling around vast amounts of iron in the gym, day in and day out.
In the absence of any other forms of training, flexing can yield minor strength and muscle gains. But you’re much better off spending your time doing push-ups, dips, squats, deadlifts and all of the muscle-building movements that humans have truly been perfecting since the 1800s. That way, when you eventually decide to flex in the mirror, it’s as a first-rate post-workout celebration, not as a second-rate muscle-building dodge.