My best deadlift is 2.5x my bodyweight (180kg at 70kg). But recently deadlifting has caused me some lower back pain / soreness. So I decided to strip the weight down to 50kg to concentrate on technique, and focus on lifting using my glutes and squeeze them as hard as possible. But this didnt help, and I still had 3 days of soreness after lifting.
Im pretty certain my technique is almost perfect at such a low weight, so do you think the problem is inactive glutes and tight hamstrings and hip flexors? (I definetly have some anterior pelvic tilt). Like I said I tried my hardest to squeeze my glutes, but in the bottom position I squeezed them as hard as I could and felt no contraction at all.
Also when concentrating on technique and working hard to keep my shoulders over the bar I really felt my middle back working hard. I have a poor head forward posture. Any thoughts on this?