## 4 Discussion  
The present study aimed to investigate the biomechanical differences between healthy and injured first-division softball players in a common throwing movement performed in an ecological environment by means of wearable inertial sensors. The most important finding of the present study was that the shoulder-injured players showed a lower ROM in the shoulder, elbow, and trunk joints than the healthy ones during a common throw. These findings suggest that, even after recovery and return to play, athletes may continue to exhibit conservative biomechanical strategies to protect themselves against re-injury or they may display a reduced ROM due to structural impairments or sensations of pain. Considering whether these changes in the ROM are protective adaptations [18] or if they could potentially predispose athletes to other injuries in the future due to compensatory mechanisms [3,16] is crucial for rehabilitation, post-rehabilitation, and training programs. The kinematic results of the present study show a consistent lower ROM across all joints' movements analyzed, with the exceptions of shoulder abduction-adduction (during the pickup phase), trunk flexion/extension (during the pass phase), and trunk external-internal rotation (during both phases). However, these differences were not statistically significant. In the pass phase, injured players showed a significantly lower ROM in all the shoulder's movements. However, contrary to our expectations, the players did not demonstrate differences in trunk or elbow kinematics, which are typically compensatory movements that can help maintain a high level of performance when throwing [6]. This lack of compensatory activity suggests that the reduced shoulder ROM directly impacts throwing mechanics, potentially hindering the performance rather than adapting to maintain it [28]. Reduced joint ROM can be attributed to several factors, among which pain is notably significant. Pain in the shoulder is a well-recognized factor that can lead to a decreased ROM [29]. However, in this study, softball players did not report experiencing pain in their upper-limb joints before or during the trials, suggesting that the observed biomechanical changes were not influenced by acute discomfort, but may instead reflect other adaptations. These results may underscore the persistent impact of shoulder injuries on throwing kinematics. [PERSON] et al. (2002) observed that athletes often exhibit altered shoulder mechanics post-injury, which may not fully return to pre-injury patterns even after perceived recovery. Similarly, [PERSON] et al. [18] found that high-school and collegiate baseball pitchers who had undergone an ulnar collateral ligament reconstruction showed significantly lower degrees of elbow extension compared to the healthy controls. However, they did not find a reduced ROM in injured baseball pitchers from before to after ulnar collateral ligament reconstruction [18]. This raises the question of whether players exhibiting a reduced ROM might be more susceptible to injuries during a throwing movement, independent from previous injuries. Shoulder ROM is essential for preventing injuries in athletes, particularly in sports involving overhead movements [3]. A restricted shoulder ROM has been associated with an increased incidence of shoulder injuries [30]. For example, in baseball pitchers, inadequate shoulder external rotation is associated with a higher risk of shoulder injury and the need for surgery [31]. Furthermore, generalized ligamentous laxity has been identified as a predisposing factor for shoulder injuries in athletes, emphasizing the importance of maintaining a proper ROM to prevent such injuries [32]. To the best of our knowledge, this was the first study to investigate the differences between healthy and injured position softball players throw. Most research has traditionally focused on pitchers' pitch [18], given the higher incidence of shoulder injuries in such a population.