When two characters arm-wrestle, the result is determined by each character making dice rolls using his/her ST + Combat (Arm-wrestling). Each round (i.e. set of dice rolls), the character with the higher dice roll result gains an advantage in the arm-wrestle equal to the difference between his/her dice roll result and that of his/her opponent. This is added to his/her total advantage (if he/she is in the lead) or deducted from the opponent's total advantage (if they are leading).
When the total advantage obtained reaches 10 points, the character with the advantage wins.
For example, Cogan the barbarian is arm-wrestling Ben Ruben. Cogan has a ST of +4 and Combat score of 6 1/2 (with no specialism in Arm-wrestling), giving him a basic value of 10 1/2 for arm-wrestling. Ben Ruben has a ST of -1/2 and a Combat score of 5 (again with no specialism in Arm-wrestling), giving him a basic value of 4 1/2. Cogan chooses to roll 3D + 1 1/2, Ben Ruben 2D - 1 1/2. On the first round, Cogan rolls a 1, 2 and 3 making a result of 7 1/2. Ben Ruben rolls a 6 and a 5, making a result of 9 1/2. Ben Ruben takes a 2 point advantage. On the second round, Cogan rolls a 4, 5 and a 6, making a result of 16 1/2. Ben Ruben rolls a 3 and a 5, making a result of 6 1/2. Cogan turns Ben Ruben's 2 point advantage into a 8 point advantage to Cogan. On the third round, Cogan rolls a 3, 4 and 3, making a result of 11 1/2. Ben Ruben rolls a 2 and 3, making a result of 3 1/2. This takes Cogan's advantage to 16 points - Ben Ruben's arm hits the table with a loud thunk!