One major problem with this machine, is that it exhibits vertical movement at its back end when you are involved in a serious workout - especially with some elevation and resistance. This is accompanied by an audible "thump" Noise. You can see some of vertical movement. At first, I thought this could be due to the floor being uneven. Adjusted the floor levellers behind but the noise and vertical movement persists.The only fix I have been able to come up with is to stack a couple of weights on the back end of the machine. This more or less solves the movement issue but there is still some odd noise associated with a heavy workout. All mechanical connections are well-torqued and the machine is only a month old.