You mean lose right? You don't shag your back at all if you have good form - in fact it's even better at strength and core development if you can lock your core. It makes it even more imperative for getting the form right though, that I agree with. Which then means strength and gains are much more achievable as your hitting the shoulders in a much more isolated fashion. You don't have to explain what compound and isolation exercises are mate I'm well aware - but thanksFor a beginner as I said, using a smith machine is quite a good way to start off - though if you're trying heavy weights as CW suggested it's not bad either, but that's about all the smith machine is good for, I don't feel much benefit from it personally though. I know enough about heavy deadlifts (
) and other compound exercises that work the shoulders, but I like to "attack" my shoulders from time to time in a very isolated way. Hence doing unsupported DB shoulder presses. I don't do them exclusively, I do them from time to time to perfect my technique and work on the stabilising muscles. You'd only screw your back up if you're one of those idiots that arches his back and pushes with the wrong part of your body. Lock out your core and you'll find a lot of strength is released when it comes to that sort of exercise. Same with squats and deadlifts - strong core = strong lift.
Isolation should only be used as a periphery exercise, the main exercises should be compound. You still havent answered why you dont use a back rest? For a strong core? Do sit ups or squats not a shoulder exercise.
