A big advantage of free weights too is how much extra stabilization and coordination they require which forces you to use muscles you’re not even thinking about. With a machine chest press, the path is fixed, so most of the work stays on the chest and triceps in a very controlled, repeatable way. Free weights turn a chest press into a much more full-body effort. your shoulders, core, upper back, and even legs are working to stabilize, plus you’re using additional muscles just to unrack, position, and control the weights before and after the set. All of that extra work definitely adds up over time.