Stats- 35 y/o 6'1" 210lbs training 8 yrs train alone
When I squat I have a tendency to lean forward on the eccentric phase of the lift which involves my lower back and I have an old back injury. (broke on a dirt bike @ 16) and my back gets very tight and sometimes have to lay on the gym floor. If i have a spotter that berely keeps me pulled back on my heels, instead of 315 for 1 or 2 reps it is 315 for 6-8 ( I know I am a weakling, but....)
I have used plates under my heels, but I really do not feel any difference. Any advice? I do not want to stop the squat and would like to get my form correct so that I can increase the poundage. 405 was always my goal.
It might be time to more or less refine your technique and switch to box squats, try starting with an 18" box, but when you perform the exercise just don't "touch and go"...as you go down use a tempo of about 5-0-1 when you come down to the box, sit completly down and and roll you're hips foward as you come up, this will not only help with your strength but will also re-teach you the correct form in performing the exercise and by rolling (pelvic tilt forward) your hips with increase the strength in your low back and hip flexors.
Start with a light weight you can handle for 6-8 sets of reps from 5-3 with rests of 2-3mins. As you get stronger (about 2-4 weeks of 2 sessions per) lower your weight as you lower the box. By the end of this strength cycle you should be much stronger with damn near perfect form!