Well, if youre just getting back into it then for your first 2 weeks use what youre comfortable with. But if you are more seasoned then kill it baby. Use all the weight that you can on everything. What I think that thing is, is some kind of friction device. It add friction at the top part of the rep. Your bod does not know if its real weight or not. But it is more difficult to keep pushing against the resistance toward the top when using the device so that is all good.
Really all it is for is to make the top part harder for your muscles to work against. And since that is where your muscles are the strongest this provides you with a more efficient workout.
Really all it is for is to make the top part harder for your muscles to work against. And since that is where your muscles are the strongest this provides you with a more efficient workout.