An isokinetic contraction is a type of contraction in which the muscle contracts at a certain speed. During this contraction, the muscle produces maximum force at any point of the movement and the contraction rate is kept constant. Isokinetic contraction is usually performed with isokinetic test systems. The isokinetic force, on the other hand, is the maximum force produced by the muscle during isokinetic contractions. This force is measured at the angular velocity at which the muscle moves and at a certain level of resistance. Isokinetic strength is used to evaluate muscle strength and performance and helps to monitor the muscle performance of athletes or individuals in the rehabilitation process. There are some important advantages of isokinetic contraction and isokinetic force. It can also be used to determine the ratios and balances between muscle groups. Isokinetic contraction provides maximum tension during contraction by loading the muscles equally at every point of the joint motion angle. Isokinetic test systems are advantageous in terms of safety. The devices used during the test apply resistance compatible with the force produced by the person during the movement, which prevents the tester from encountering more force than the muscles can withstand. This minimizes the risk of possible injury during testing. isokinetic contraction and isokinetic strength are important tools used to evaluate and monitor the performance of muscles. In this context, isokinetic contraction and isokinetic force are discussed in the relevant section.