Since four fingers are stronger than one and the thumb acts as an obstacle for the bar to roll the barbell is secure and a lift is rarely missed because of weak grip. This technique is also used by some powerlifters during heavy deadlifts in order to avoid biceps tears and uneven lifting.
However, does the hook grip actually develop forearm and grip strength?
Since the lifter is gripping the bar during the execution of any Olympic lift, the forearms are heavily involved in any exercise done with the hook grip.
The hook grip, however, does not require much strength and in consequence your forearms do not receive as much stimulation for growth and strength increase.
That’s why you should never rely on the hook grip for every set you do.
There’s absolutely no need to do your warm-up deadlift sets with a hook grip. Let the forearm get some work.
While the hook grip acts as a ‘human lifting strap’ it still hurts a lot. That’s because the bar is constantly pressing at the thumb and digs hard into it. Some lifters have even pulled their nails off during heavy lifts done with the hook grip.
The pain usually goes away after a certain period of adaptation but it’s never the most comfortable experience.
A good thing to do would be to use chalk and wrap your thumb with athletic tape to protect the skin and provide some cushioning.