Great little tool for Barbell curls, not nessessary at all but it keeps you from cheating.
Arm Blaster Board.
Those work fine, until they break as you’re in the middle of a heavy 8-rep set, and you have about 1/19th of a second to do all you can to not throw your back out as the strap breaks and the support falls away.
As for doing “strict” curls…if your elbows leave your ribs, before your forearm touches your bicep, you’re using the front delts for assistance. Whether that’s “acceptable” or not is up to you, based on why you’re doing the exercise in the first place.[/quote]
I found that using the arm blaster for a month if your form isn’t so good teaches you to curl better when you stop using it.