The goal of this study was to generate national estimates of injuries associated with mechanical home exercise equipment, and to describe these injuries across all ages. Emergency department (ED)-treated injuries associated with mechanical home exercise equipment were identified from 2007 to 2011 from the National Electronic Injury Surveillance System. Text narratives provided exercise equipment type (treadmill, elliptical, stationary bicycle, unspecified/other exercise machine). Approximately 70 302 (95% CI 59 086 to 81 519) mechanical exercise equipment-related injuries presented to US EDs nationally during 2007–2011, of which 66% were attributed to treadmills. Most injuries among children (≤4 years) were lacerations (34%) or soft tissue injuries (48%); among adults (≥25 years) injuries were often sprains/strains (30%). Injured older adults (≥65 years) had greater odds of being admitted, held for observation, or transferred to another hospital, compared with younger ages (OR: 2.58; 95% CI 1.45 to 4.60). Mechanical exercise equipment is a common cause of injury across ages. Injury awareness and prevention are important complements to active lifestyles.