One of the biggest misconceptions that has been around for decades is that in order to gain muscle mass and gain weight you "must" do certain exercises.
9 times out of 10 those recommended are "the big compound movements", like bench presses, squats, and military presses.
Most advise to stick to these "basic" movements if you are looking to build muscle fast, and to avoid so called "shaping" exercises, such as crossovers, flyes, laterals, and leg extensions.
Some competitive bodybuilders don't use shaping movements until the final few weeks of their contest preparation.
The misconception behind this rational is that big, compound movements are for building mass, and shaping exercises are for defining a muscle.
Wow, that couldn't be further from the truth!
Just take a step back and look at the whole picture for a second.
Do you really think that a muscle has any idea whatsoever if you are doing a "compound" movement or a "shaping" movement?
The only thing muscle fibers recognize is resistance, stress, and tension, regardless if that's coming from bench presses or flyes...regardless if it's coming from free weights or cables...regardless if it's coming from a compound or a shaping exercise.
The whole idea that isolation / shaping exercises are only good for defining a muscle and not for building size is one of the biggest myths around.
Regardless of what specific exercise you are performing, if you are providing enough tension the muscle is only going to do 1of 2 things, stay the same or grow...not define itself.
Any weight exercise works the muscle fibers which, when done properly, will build it.
So, yes, flyes will help your pecs grow.
Yes, side laterals will make your shoulders bigger.
Yes, leg extensions will add size to your quads.
If you are taking your muscles to their limit with the correct bodybuilding workout technique, the muscle is going to grow, period.
Competitive bodybuilders think that shaping exercises help bring out more definition or "striations" in their muscles, when in fact what's bringing that out is the fact that they are dieting any body fat that's covering up that muscular definition.
It has nothing to do with the exercise.
Let's get one thing straight: weight lifting exercises build muscle...period.
Definition, shape, striations, etc., comes from a proper bodybuilding diet that will burn body fat.
Also, it's easier to get a deep muscular pump with isolation exercises.
Isolation exercises work the muscle in such a way that no compound exercise can because it "isolates" the intended muscle you are working more.
So, include both types of exercises in your workout program for the ultimate development.
