Like hazbin said,its easy to move the dumbells back to your knees when you finish,the weight of the dumbell then pulls you up off the bench.Obviously you have to finish the set with the d/bells in the top position.All my d/bells are what i`ve made myself and welded and i train at home in the garage,so i didn`t like to have to drop the weights now and then,in case the d/bells broke.So i made myself 2 short benches that fit at the side of the regular bench at a 45%angle and if i can`t complete the rep and end up in the bottom position i just lower them to the short benches.Then i made myself a table out of 5 inch solid oak with the top at shoulder height to do d/bell shoulder presses,i lift the d/bells on,sit down on the seat,tip the bells back and they are in position.When i finish i just lean forward and put the d/bells back on the table top.