Purpose: The purpose of this study was to provide an epidemiological profile of injuries sustained by participants in fitness activities in Victoria, Australia, based on hospital admissions and emergency department (ED) presentations and to identify the most common types, causes, and sites of these injuries. Method: Hospital-treated fitness activity-related injury cases were identified from International Classification of Disease activity codes (for admissions) and from text narratives of injury events (for ED presentations) from 2003 to 2010, inclusive. Cases were categorized as being associated with aerobics/group exercise (n=252), resistance/weight training (n=830) or "other equipment" (motorized and general gym equipment; n=1,156). Participation information was taken from the Exercise, Recreation and Sport Survey. Results: Overall, 2,238 cases were identified and 11.6% of all patients with ED presentations were subsequently hospitalized. Those participants with aerobics cases were generally female (76.6%) and aged 25 to 34 years old (35.3%), with injuries to the lower limbs (59.1%) and due to falls (57.9%). Resistance-training injuries increased significantly during the 8-year period (by 215.7%; 95% CI [133.5, 326.9]) and generally occurred in male participants (78.0%), in people aged 15 to 24 years old (36.4%), and with injuries to the upper limbs (45.1%) caused by being hit, struck, or crushed by weights or fellow exercisers (71.4%). The "other equipment" cases were equally distributed by gender; they occurred most commonly in people aged 15 to 24 years old (27.8%), with injuries to the lower limbs (41.5%) and due to falls (57.6%). Across all categories, dislocations, sprains, and strains were the most common injury types. Conclusions: Fitness activity-related injury prevention strategies should be targeted at different subgroups according to the type of fitness activity being undertaken.