Isokinetic exercise is a dynamic muscle workout performed at a constant speed using robotic or hydraulic equipment that adapts resistance to muscle tension, allowing the muscle to work at maximum load throughout the movement. The Biodex® system, used in this study, enables the evaluation of muscle strength and the development of rehabilitation protocols that focus on reinforcing specific muscles from early post-operative phases, complementing traditional physiotherapy. Isokinetic testing is valuable for assessing muscle function and imbalances following shoulder instability surgery, aiding in tracking rehabilitation progress. Literature on isokinetic evaluation in shoulder pathology is limited; however, key studies between 2000 and 2025, including research involving 111 patients, demonstrate the significance of muscle strengthening after surgery. This chapter reviews the application of isokinetic testing in shoulder rehabilitation, supported by data from the authors’ institution, highlighting its effectiveness in improving recovery times and reducing sports absence in patients with unstable shoulders.