[EnterTheirMinds]

I do a few things for grip strength. First, take a dumbell and put however much weight on it. I use around 30-50 pounds (in total, not on each side). Have your arm so the underarm is facing up and simply use only your wrist to move the weight up and down. Do it slowly. Second, using also the dumbell, turn your hand so your forearm is now up and do the same thing. Do it slowly. Third, take something like a brick or a dumbell and hold it. Ideally, hold it out so it's inline with the shoulders or hold it so it's straight out. That way, you can exercise something else also. Fourth, pushups on fingers or knuckles. Fifth, take a dumbell and only put weights on one side. Hold this next to your side and only use your wrist to move it. The longer the bar, the harder it is with the same weight.

In judo and grappling, you need strong wrists and grips.

I found the person at my dojo with the strongest grip is the oldest, around 60 years old or so. He's a mechanic for a factory (i think paper factory) and has an incredibly strong grip.

Also, a way that may have not been thought of - serving food. Yes, you can get nice tips but also have to carry so many plates (and sucks when they're heavy) all day long, ideally in both hands. Carrying around one heavy plate isn't so bad but doing it for hours, especially while moving around makes it harder.