Armwrestling is a strength sport with 160 countries affiliated to the World Armwrestling Federation. It is contested between two opponents who aim to lower the opponent's hand to the finishing pad by externally rotating the opponent's shoulder and extending the elbow. The specific movement requires a lot of strength and power, mainly from the upper limb, which is in dispute. In this study, we evaluated with an isokinetic dynamometer the balance of concentric forces that perform internal and external shoulder rotation. The results showed significant differences in the ratio between internal and external shoulder rotators in the power tests where the mean found was 57% (p=0.001) against 66% of the recommended value for the power of external rotators compared to internal rotators. There was no significant difference in the strength test, and the mean was 58% (p=0.064) against 64% of the recommended value for the strength of external rotators to internal rotators. We conclude that the arm wrestlers studied developed significant differences with more strength and power for the internal rotators compared to the external shoulder rotators. This imbalance can cause injuries to the tested joints and muscles involved in these movements