I have used the thumbless grip for a long time on bench, OP and squats. I think there are quite a few benefits to doing so.
1) the freedom of shoulder range. After I tore my pec/labrum, it almost became essential to use a thumbless. When you hook the thumb around the bar, it locks the shoulder into a restricted position. This may be okay for those who’ve never suffered shoulder injury, but for those who need a little leeway, it’s a game changer.
2) the thumbless grip also allows me to load the bar further down the palm, at the base of where the thumb would be. I find this position allows for better wrist alignment and support above the forearm and the bar is more centered over the joint.
The main drawbacks I hear are...
1) “you cannot squeeze the bar as tightly.” This may be true, but I’ve never found this to be a limit in my strength on the lift. You are still squeezing the bar immensely without the thumb. I find the better shoulder and wrist position makes up for this. When doing a OAP, we still squeeze the floor, even with an open palm.
2)” the bar may slip out and cause injury.” Never (knock on wood) have I lost the bar, even on pressed that I missed. I usually am forced to do my OH presses sans rack, meaning I clean the weight first. My fingers have become strong enough to clean my press weights with a thumbless grip.
As far as pressing with no thumb, it is also mentioned in PTTP Professional as a viable option. Jim Wendler and Christian Thibaudeau both also advocate its use as well.
Here’s CT’s article
This type of grip eliminates shoulder and triceps pain in heavy benchers. And yes, it's safe if you're not an idiot. Here's how to do it.
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