Judo,
It depends on the position you are playing. if you are on the line, look into filipino martial arts or Kali. They have some of the best hand drills known. Called “Hubud”, there are literally hundreds of different hand drills. If you are defensive back, perhaps judo, but only for the grip. Judo is predicated on very specific energy, usually when you are already in the grip, then you throw or trip. I not sure you would want to do that. So, if you had a specific position, then you could find a martial art specific to the nature.

Hope that helped.

Stacy

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