Couldn't agree more. I have a spinal tumor that has damaged my back very badly and also equates to leg disfunction. I exercise extreme care with all of my setup. A very solid drum stool is essential to good posture. Even a small amount of movement in the stool base promotes the body to compensate using the lower back. From a RSI point of view, that's really bad news. Look at Collins video's and you'll see he's bent over quite badly most of the time. This commonly causes uneaven compression of the discs and sometimes leads to the disc protuding into the centre of the spine, disturbing the leg nerves. Extremely painful. I know because I suffer from that too. Especially younger players, beware. You may think you're indestructible, I know I did, but your not.