[andromeda1111]

The exercise you are describing are called "Hack Squats" and they place a tremendous amount of force directly on top of the spine - basically compression, this exercise is one that I did for a very long time and ended up really screwing up my spine, there is actually only a few leg press machines that I have found that are safer on the spine. One is designed by Cybex and it is called the "Squat Press". the other is called the "Classic Leg Press" also by Cybex and Nautilus has a new leg press that I like, I have used these and own one of them - the squat press is a leg press that simulates a squat, I place a foam pad directly in my lower back area.

Being that the hack squats cause spinal compression, this can affect the cervical area, you also must have very strong upper back muscle in order to perform this exercise safely.

I do not believe that your weight-lifting days are over, you just need to do the right exercises on the right equipment. Being able to workout safely with a spine issue is all about perfect ergonomics... and these must be applied to correctly designed exercise machines, not all of them are...AND knowing how to properly contract the right muscles at the RIGHT TIME. Any questions feel free to email me, I would be happy to help you.
Andro1111