As an old and current weightlifter (35 years of it), I'm going to advise you guys to work on core stengthening as well as your arms and legs, etc. The core exercises protect your back from damage. And, I also suggest that for squats, you move to the machines. As a result, I squat (seated and pushing up at about a 45 degree angle) 300 lbs without putting any needless stress on my back.