i see a lot of people doing squats or leg press and they just LOAD ON THE WEIGHTS like its a competition to see how much they can stack on the ends. (many of them only ever get partial reps too)
is it not better to pre-exhaust your legs a bit, by leg extensions or similar, and THEN go do the big exercises of squats or leg press.
you'd need less weight and your back, bones and joints would be less stressed too but still you'd be burning those leg muscles.
H - 185cm (6'1") W - 85 kg (188 lbs) Age - 38
I definitely pre-exhaust my quads before I train my quads. I usually do a lot of leg extensions with incredibly strict form and/or leg pressing.