Not Isolating Muscles
If you are a beginner bodybuilder, your first instinct might be to workout as hard as possible and cover as many muscles as possible. But there is a difference between compound exercises and isolated exercises.
Compound exercises workout many muscles – but when you do this, the strongest muscles do most of the work and the weakest perform the least. So if you only do compound exercises, you will never really see high quality muscle gain.
You need to isolate specific muscles in order to maximize muscle gain in the naturally weaker areas. That’s the point of bodybuilding – to create a perfectly sculpted physique. Sometimes that means stimulating very specific muscles that would accidentally get ignored with the wider range workouts.
