I started using hook grip last week. I can secure my thumb with most with all my fingers except my pinky. After training my thumbs felt tight so I googled some things about stretching the thumb to get as much surface area when using the hook grip. Hope this helps some. I use this stretch everyday now. I can now get my pinky locked in over my thumb now with a deadlift bar.
Unable to Hook Grip
Unable to Hook Grip
