Muscles dont know weight, they only know failure.
Well, you can quickly reach failure doing ultra slow curls with 10lb dumbells but it will
never cause the adaptation that heavier weights would. Muscles know
tension.
Doesn't matter if it's isolation or compound movements, the higher the tension the better.
If we take the bench press. If you do wide grip benches, somewhat fast motion with quick reversal of motion in the stretched out position, the tension on the pectoralis will be huge. it would be very hard to duplicate with a pec deck. Wonder why no one tears pecs on pec decks? The tension is too low.
BUT... the heavier the load the greater the injury risk. If there was no injury risk, hypothetically, the heavier the better.
Every pro instinctively knows this, even if they claim the contrary. How many of them use TOO MUCH weight to even do the exercises correctly? ALL OF THEM, pretty much.
Milos was always preaching how load doesn't matter. Then how come he did those 900lb hacks and 6 plate squats when he could have achieved the same with 225lbs?
