If you’re natural, the bigger you wish to get, you must train ever more intensely to get the same results. For example, you can wildly swing 200 lb cheat curls and give your lower back a great workout, or you can use 115lbs, put your back to the wall, where you can’t cheat, elbows down and back near the wall, start with the bar 4 inches away from your thighs, slowly curl up, and without your elbows going forward and working your front delts, squeeze and hold at the top for 4 seconds, and lower back to the starting position, but never all the way down, and go to failure on the set. Now that is intensity!!!! That’s how you grow.