Here’s a great (NSFW) video about grip strength:

An outstanding excerpt from the related article:

Here is an old video of us hitting heavy support grip holds for time on the GRex.

Support grip is one component of grip strength. The others are crush, pinch, wrist postures and hand health.

Grip strength is the forgotten element of functional training and is essential since the hands are involved in all athletic and strength training endeavor (including building muscle or losing fat).

In fact the hands are the end point of the kinetic chain, so they must be developed if we hope to transfer the power created and accumulated from our bodies and express it through our hands.

I cannot stress how important the bolded part is! Having a crushing grip will carry over well into almost all sports for that specific reason. It makes your force application technique better in the baseball/golf swing, the drive from a lineman/flanker, and the slap shot from a hockey player.