When i first started working out, i a adopted what i think is currently called a brow split. And every day of the week i was training a a given muscle group. Onceye, has the science a moved past that? Yes. When you're on lots of anibolic steroids, your body can handle much more volume than you could if you were all natural. So they broke the body, art, the body up into body parts so that they could work out for an hour. That's one reason why they went to body part splits. We can measure the muscle building signal that we see in the body through something called muscle protein synthesis. It peaks at 24 to forty eight hours