['Shoulder activity level may be a risk factor for shoulder instability, an indication for surgical intervention, and a risk factor for failure of operative stabilization.', 'Patients undergoing shoulder stabilization surgery have a higher activity level compared with sex- and age-matched healthy controls.', 'Cross-sectional study.', 'Level 2.', 'Patients undergoing shoulder stabilization surgery aged 18 to 50 years were prospectively enrolled. As part of data collection, patients completed a previously validated shoulder activity scale, which generates a score reporting frequency of activity ranging from 0 (least active) to 20 (most active). The activity level of these patients was compared with sex- and age-matched norms for a healthy population with no history of shoulder disorders.', 'A total of 409 subjects (343 male, 66 female) undergoing shoulder instability surgery completed the activity scale. Seventy-seven percent of patients had higher shoulder activity level than sex- and age-matched controls. Seventy-nine percent aged 18 to 30 years had a higher shoulder activity level than controls, with an identical distribution for men (79%) and women (79%). Among patients aged 31 to 50 years, 70% had higher activity than controls. However, men were more likely to have a higher activity level than controls (72%) versus women (59%). In patients aged 18 to 30 years, median activity level for instability patients was 14 in men compared with 10 in controls, and 13 in women compared with 8 in controls. In patients aged 31 to 50 years, median activity level was 13 in men compared with 10 in controls and 10 in women compared with 8 in controls.'] Do patients Undergoing Shoulder Stabilization Surgery Have Elevated Shoulder Activity Compared With Sex- and Age-Matched Healthy Controls?