First things first, if you’re training with barbells than you should know that the hook grip is different in kettlebell training, I mention this because I’ve had this “that’s not a hook grip” plenty of times. In CrossFit the hook grip is with the thumb over the bar and the fingers closing the grip over the thumb. In kettlebell training there is the Hook Grip and Closed Hook Grip (AKA C Grip) and the thumb is over the index finger or both the index and middle finger.
Why the thumb is between the bar and fingers instead of the thumb over the fingers still puzzles me? Perhaps the first is a slightly stronger grip, but also a lot more uncomfortable grip.
If you’re training CrossFit or with kettlebells you’ve probably been told to have a hook grip when snatching (CF) or deadlifting (CF), when doing single arm swings (KB) or other movements that involve the down phase of the swing (snatch, swing clean etc.), but I’m a big believer in explaining the ‘why’, if you can’t tell me the ‘why’, I probably won’t remember, and I believe a lot of people are like that —unless they just follow blindly—, hence the reason why it’s important to know and explain the ‘why’.
The hook grip is to not only get a better firmer grip on the bar or handle but also to relieve some tension on your forearms, if you are experiencing finger cramps, tight forearms, muscle soreness or other issues in your forearms, try switching to a hook grip. This is especially the case when just starting out with training and your forearms and fingers still need to be conditioned.
The muscles of the forearms close the fingers into a fist or closed grip and keeping them closed while holding weight (barbell or kettlebell) creates a constant tension on the muscles, when not conditioned or doing high volume reps this can turn into injury. A closed hook grip or just hook grip for crossfitters relieves some of the tension from the forearms, further more, it involves the index finger more in the grip, usually the index finger doesn’t play a big role in the grip, you’ll notice this when looking at the calluses on your palms.
Displayed above are the forearm flexors, they are located on the palm side of your forearm, you use these muscles when you curl, grip or hold things.
I have created an awesome PDF with all kettlebell training grips explained, you can download it for free.