I can squat 405 ass to grass and over 450 parrallel(not much more raw). so this trainer comes up to me and tells me if i put on 495 bend my knees slighlty and count to 15 bc ill work my muscles fibers better with "Static training" so i do that and its easy. He says go up 25 pounds i go to 585 instead and do that for 15 seconds and that was easy and he told me that all i need for squats and that will bring my parallel squat up a lot. so has any one tried this method and found it even worth while? It's kind felt wierd on my knee but thats about it.
A few coaches on here have talked about something like this. Walking out with a supramaximal weight "fires up" your CNS and makes your real 1RM feel lighter.
I think isometrics are a great training tool, just do them in bottom position rather than the top.
Supramaximal holds can be used as a potentiating tool, but if you are trying to gain muscular strength (rather than just fire up your nervous system), try sets of 5-10 second isometrics at slightly below parallel. I found they had great carryover to my oly squat.