In this research elbow flexion has been analysed and the moment of muscles and the reaction force exerted on the elbow is calculated in the range of motion. The moment of muscles indicate the performance of movement and the reaction force of the joint is believed to be one of the most important causes of damage, something which hasn’t been studied thoroughly enough in previous researches. To that end, we use ADAMS software which is one of the most powerful ones available in dynamics analyses. The results indicate that the maximum torque of the arm occurs at 96 degrees and it decreases in the beginning and the end of flexion. The reaction force of the elbow in the beginning of motion is at maximum amount and then decreases to 107 degrees, and from that point on it increases up to the end of the motion. These results indicate that the optimum range of elbow flexion occurs in the mid-range of flexion, approximately at 58-140 degrees.
