Swimming and Shooting in Water Polo Players: Associations Between Shoulder Muscle Activation and Shoulder Pain

This cross-sectional study aimed to compare shoulder muscle activation patterns during front-crawl swimming and overhead throwing between water polo players with unilateral shoulder pain and matched asymptomatic players using surface electromyography analysis. A total of 16 water polo players were recruited and divided into 2 groups: athletes with unilateral shoulder pain (pain, n = 8) and asymptomatic controls (control, n = 8). Surface electromyography analysis highlighted activation of 9 muscles of the shoulder complex during the overhead shot task and front-crawl stroke task. During the overhead shot task, water polo players with shoulder pain showed lower activation of the serratus anterior (F1,14 = 6.767, P = .021, η2p = .326) and upper trapezius (F1,14 = 7.864, P = .014, η2p = .360) compared with controls. Lower activation of serratus anterior (F1,14 = 20.005, P = .001, η2p = .588) and upper trapezius (F1,14 = 18.287, P = .001, η2p = .354) was found in the pain group compared with controls, even during the front-crawl stroke task. Overall, these findings suggest water polo players with shoulder pain could present a reduced activation of scapular stabilizers during sport-specific tasks, which may contribute to altered scapulothoracic kinematics and increased shoulder injury risk.