There are many different moves in arm wrestling.
The three most common are: Hook, Toproll, i Press.
Arm wrestling is really a leverage sport. These moves all create different types of leverage, helping you to beat your opponent.
Because different moves work for different individuals, it is important that you figure out which move provides you with the best leverage advantage and therefore best chance of victory.
The hook is the most common move in arm wrestling. You are probably familiar with the hook, because it is the move that is used when arm wrestling is portrayed in bars and elsewhere on TV.
It is considered an "inside" move, meaning you are trying to beat your opponent's arm instead of his hand (as you do in a toproll). To be successful in a hook, you should be stronger than or at least equal to the strength level of your opponent. If you believe that you are not as strong as him or her, try toprolling instead.
The toproll is a great move to beat your less experienced friends with. You are trying to put tremendous pressure on your opponent's fingers, causing his hand to open up and allowing you to gain leverage.
If you do it quick enough, he will have no idea what happened!
The press is one of the purest power moves in arm wrestling. If you are confident that you have superior upper body power (especially chest and triceps) to your opponent and are at least equal in bicep and forearm strength, this is a good move to perform.
The press is also a good move to use in a long tournament. Unlike the hook and toproll, which rely most heavily upon the biceps and forearms, the primary muscles used in the hook are the triceps, shoulders, and chest. Thus, a good way to give your bi's and forearms a rest during a long tournament is to throw in a press when you can.
10.03.2010. 
See video The Hook technique
