Grip strength is essential in MMA. Grapplers need a very powerful grip but standard barbells and dumbbells are too skinny to help them develop the strength in their hands and wrists. Fat Gripz, however, are different. The thicker diameter is much closer to the size of a person's wrist which makes them perfect from developing grip strength for grappling.
It goes without saying that extreme power in the hands, wrists and forearms is a necessity for success in arm wrestling competition. Many top arm wrestlers including Mens World Champion, Geoff "The Haleraiser" Hale and Womens World Champion, Sarah Bäckman, use Fat Gripz.