pretty much what he said is troof.
most people don't know to rest. when you work out, your muscle
tissue tears, releasing amino acids. when you rest, the acids then
layer over your muscles as a healing process, which builds more
muscle over time. if you work out too often, its almost like a wasted
attempt, because you're not giving the acids time to restructure the
muscle, and you're then constantly tearing the tissue without giving
it time to build itself up.
hence the reason i only train every other day, and i don't dedicate
myself to weekends because i'm usually too busy to get to the gym
anyways.
also, if you don't switch up your workouts, you DO reach a plateau.
this is because your body learns the movements and habits, and
eventually has a lesser reaction to the workout. there are millions
of different ways to lift weights, but i favor full body lifts.
this is pretty much what my routine consists of:
each gym day, i'll hit two full body lifts:
-Squats
-Shoulder Press
-Dead Lift
-Chin up/ Pull up
there's more but i forget them...
i'll do my two full body workouts, and then for the rest of the time
i'm there, i'll focus on a category of workouts. ie: pulls, pushes, etc.
in between each set, i rest 30-60 seconds. its important to rest.
flexibility is also just as important as working out. you don't
necessarily HAVE to be flexible, but it looks kinda funny when you
get really built, but don't have the flexibility to put your arms down
by your sides... i'm not suggesting yoga, which is actually pretty
damn good for you, but i spend a few minutes warming up and
capping my gym days with lots of stretches.