-
I'd suggest dropping the weight to something where you're not worrying about the last couple of reps. Work on depth and form , and then slowly increase the load. Doesn't have to be 5kg or 2.5kg every week .
It also helps to try a figure out where any weaknesses or flexibility issues are, so you can build up that particular area with accessory movements . I had to spend time building delts and triceps to get through a bench plateau .
Belts can help with bracing and stability too if you're not wearing one already.
-
Crack on with the program, failure is part of a program like stronglifts. As long as you're still hitting depth, not going as low is fine. I use the safeties for all my working squat sets. I know how to dump the bar without them, but it's nicer not to have to.
I will say that I think the ways to circumvent stalling in stronglifts/starting strength is one of the drawbacks. Comparatively a program like greyskull LP where you drop the weight, but do amrap sets still (so you are still pushing yourself even with a lighter weight), and increase faster if you get 10+ reps on the amrap, or GZCLP where you reduce reps + increase sets (with amrap still), but keep same / increasing weight, are better ways to deal with it IMO.
re: belt / shoes etc being necessary, it's about what you want to use. you never have to use them if you don't want to, but there's not some weight where they become an acceptable tool, they always are. I like using my belt on some lighter sets partly to practice bracing into it properly. If you've not use a belt before, give it a try and see how you like it.
After writing this I did see that you said you've been doing 3*12 for twenty years, if you have been lifting for a long time (even without doing 5*5) then the amount you will be able to reap from a program designed for beginnners is limited, as Bainbridge says it may be worth looking into intermediate programs if you repeatedly stall.
I started StrongLifts a month ago, progression has been fine but I’m starting to struggle with squats which have always been my weakness. The last two increments have been so heavy. I can still complete but I’m starting to use the safety bars and I don’t go as deep as I used to and I’m afraid I might injure myself.
I’d like to drop the weights a bit and I might as well do so now before an injury but can anyone tell me how much weight StrongLifts takes off after a couple of incompletes?