In a good CrossFit program, you will find a substantial volume of cleans and snatches. These movements boast impressive merits in terms of their effect on overall athleticism. The olympic lifts require athletes to develop speed, balance, flexibility, accuracy, strength, power, coordination, and agility. That covers 8 of the 10 general physical skills in which we seek to improve our competence. Look and you will see that no high level weightlifter lifts without the use of a hook grip!
Why is that? Why does trapping your thumb between your first two fingers and the barbell matter? The answer is SPIN! The barbell is designed to spin as you transition from the pulling phase of the movement to the catching phase. This spinning of the shaft allows the weights to not spin, and thus allows a much faster and safer transition from pull to catch. Turns out that this spin also causes the bar to want to roll through any weak point in your grip. By wrapping the fingers over the thumb, you are able to create a closed loop that essentially eliminates these weak points. Because the grip is MUCH more secure, greater weights can be lifted. By creating a more secure hold, you open up the potential to transfer more force into the bar. Driving harder and faster is how you lift more weight!
Is that all? Does using a hook grip just mean that I can lift more? No. The hook grip also allows you to lift better. One of the most prevalent faults in these lifts is the early arm bend. When simply squeezing the bar with a normal grip, it can be extremely difficult to allow your arm to remain straight. You get a feeling that to keep the grip you must bend the elbow. When you “close the loop”, it opens up the potential to keep your elbows straight through the extension phases of the lifts where the real power is created. More focus being put on the “long arms” means better lifting. Eventually better lifting, increases in speed, power and improved timing will lead to heavier lifts. But more importantly, better lifting is, well, BETTER!
The hook grip can be difficult to get started on, but there is no adequate substitute! You have to just do it! It will improve with time and practice. Check out what Greg Everett (a highly experienced and qualified weightlifting coach) has to say about learning the hook grip.