The present study investigates shoulder joint injuries among handball players and examines their influence on athletic performance from a sports training perspective. Shoulder injuries represent one of the most frequent musculoskeletal problems in handball due to the repetitive overhead movements, physical contact, and high-intensity demands of the sport. The research aimed to identify the most common shoulder injuries experienced by handball players, evaluate the role of physical preparation and warm-up in injury prevention, and determine how these injuries affect technical and physical performance. A descriptive-analytical research design was adopted, and data were collected through a structured questionnaire administered to senior handball players from clubs in Bouira Province, Algeria. The questionnaire focused on three principal dimensions: physical preparation, warm-up practices, and relaxation techniques. The findings indicate that inadequate physical conditioning and insufficient warm-up significantly increase the risk of shoulder injuries, leading to reduced athletic performance. Conversely, appropriate physical training, scientifically planned conditioning programs, and effective warm-up and recovery strategies contribute substantially to injury prevention and performance enhancement. The study concludes that strengthening the shoulder joint musculature and ligaments through evidence-based training methods should be an essential component of handball preparation programs. Implementing preventive training strategies can improve player health, minimize injury occurrence, and optimize long-term athletic performance.