Back up again...
After doing JM's again this week, I'm still not sure of the form. Did some searching, and found this description:
Lie on a bench - this is very important.
Take a close grip with the beginnings of the knurlings.
Take the bar at arms length like the start of a close grip bench.
Put the elbows out at a 45 degree angle - this is VERY important - must be 45 no more and no less.
At this angle you take the shoulders out of the movement and it also allows a greater weight to be used.
As the bar descends to the chin or throat, keep the elbows following a line of 45 degrees from the body. Note: the elbows must not drop below the rib cage. They must remain up towards the heavens or the ceiling for those that train indoors.
When you get it right the bar will stop as the forearm rests on the bicep. IF your elbows are up and you get it right, the bar will sort of hang there above your face as your bicep(resting on forearm) and the tricep tendon supports the weight. He noted that it may help to keep the wrist "cocked" at the bottom (ie flexors contracted)
After that just press straight up in the same path as you descended...Well, not YOU but the bar.
Jason W. Burnell
STRENGTH ONLINE:
http://www.deepsquatter.com/strength/