Here are three workout elements beginners should not waste their time on:
Machines And Cables For Back
Stay away from this part of your gym on back day! Nothing is going to give you more width and thickness than the raw basics: chin-ups, deadlifts, barbell rows and dumbbell rows. Work them hard and your back will grow, period.
Pec Decks And Cable Crossovers
Just do presses and dips for your chest until you have some good thickness, at which point you can start doing dumbbell flyes. Leave that other shit alone until you are more advanced, maybe about two years of training under your belt.
Leg Extensions
For big quads, do deep squats and add in some heavy leg presses every once in a while. You don’t need to worry about isolating your quads or trying to get more separation until you actually have the size there in the first place.