If the Bar Ain't Bendin', You're Just Pretendin'!
This hyper-machismo statement basically just means you need to lift heavy. On the surface it might seem correct. If you lift heavier and heavier weights you'll grow bigger and bigger muscles.
And to some extent that's true. Progressive overload is effective at stimulating gains. If your main goal is to get stronger, then you don't have a choice: to be able to lift big weights you must lift big weights! But...
Here's Where the Expression Falls Short
What about gaining muscle? Does hypertrophy require the use of heavy weights? The answer is no.
A study done by Cameron et al. found that if you go to failure you can stimulate the same amount of muscle growth with a light weight as you can with a heavy weight (30% vs. 80% of 1RM). The lighter group didn't have the same strength gains, but they had the same muscle mass gain. Several studies on occlusion training also found similar results.
I've experienced this myself. Because of shoulder issues I haven't been able to press heavy weights for four years now. I used to bench press 405 to 445 pretty much every workout. Now I'm forced to use lighter weights, more isolation work, longer time under tension, go to failure and beyond, etc.
But my upper body is just as good as it was. You might say that I simply maintained the muscle I'd built from the heavy lifting. That's not 100% correct because at one point I lost a ton of muscle because of kidney issues. I stopped training for months and lost 30 pounds of muscle. I've regained it all.
Sure, you can claim it's because of muscle memory. Maybe. But you still have to put in the work to regain the muscle tissue. Ineffective training would not allow you to regain all the muscle.
Maximal weights can actually be an inferior method for building muscle mass. I'm talking about using weights that you can lift for 1 to 3 reps per set. Look at Olympic lifters. Even those who can hoist 400-500 pounds overhead don't look really muscular (except for a few exceptions). A lot of powerlifters (those who don't use higher rep assistance work) also look a lot less muscular than they should considering their strength levels.
There's no doubt that heavy weights can build muscle. And progressive overload works. But to be effective at building muscle we're talking about becoming progressively stronger with 4-6 reps, not 1, 2 or 3.
But of course if your main goal is to get strong, then yeah, you'll need to lift big weights. When the muscle is gained through lighter methods, the strength gains aren't immediate because there will be few neurological improvements. Both muscle mass and neurological efficiency are important for strength gains. Remember this:
- Muscle mass = your strength potential
- Neurological efficiency = how well you can use that potential
Having a lot of muscle is like having a factory with lots of employees. On paper it should make the factory more productive. But if the employees are lazy, or if they don't work together well, the factory won't live up to its potential and a smaller, better run factory will out-produce them. It's the foreman's job to make sure the employees work to their full potential.
Same thing with strength. If you have lots of muscle but you aren't good at making it work (muscle fiber recruitment), do quality and productive work (fiber firing rate) and work together (inter and intramuscular coordination), you won't be able to produce a lot of strength. That's the job of the nervous system to make the best use of your muscles.
To improve your nervous system's capacity to direct your muscles to produce a lot of strength you must practice lifting heavy weights. That's why adding muscle via lighter training can make you stronger, but you first must learn to use that muscle by doing a phase of heavy lifting.
You can definitely build a muscular physique without moving monster poundages. But if your main goal is to be strong you'll need to include a decent amount of heavy work. Getting progressively stronger in the 4-6 rep range will work well to get you both strong and muscular.
By the Way...
If you're going to take the expression literally, then realize that different bars have different flex. Some bars (Olympic lifting bars) will bend with as little as 265 pounds; others will require 500 pounds to have a noticeable bend. If you're bench pressing with an elite powerlifting bar you could press 400 pounds and not see a bend. Does that mean you're pretending?