van den Berg-Emons RJ, Bussmann JB, Stam HI. Accelerometry-based activity spectrum in persons with chronic physical conditions. Arch Phys Med Rehabil 2010;91: 1856-61. Objectives: (1) To give an overview of the impact of a variety of chronic physical conditions on accelerometry-based levels of everyday physical activity and to identify high-risk conditions; and (2) to compare these objectively assessed activity levels with the levels estimated by rehabilitation physicians. Interventions: Not applicable. Design: Cross-sectional study. Setting: Participant's home environment. Participants: Patients (n=461) with 18 chronic physical (sub)conditions and able-bodied subjects (n=96). Main Outcome Measures: We summarized data on the level of everyday physical activity as objectively measured with an accelerometry-based activity monitor. Thirty-one rehabilitation physicians filled in a questionnaire designed to obtain their estimates of the level of physical activity in patients with the various conditions. Results: Only 4 of the studied conditions had normal activity levels (>= 90% of the able-bodied level). Persons with transtibial amputation (vascular), spinal cord injury, and myelomeningocele (wheelchair dependent) had the lowest levels of activity, less than 40% of the able-bodied level. In general, rehabilitation physicians were aware of the inactive lifestyles, but considerably underestimated the magnitude of inactivity in the high-risk conditions. Conclusions: This is the first study to provide an objectively assessed activity spectrum in a variety of chronic physical conditions. We hope this study will increase the awareness of health professionals as to which chronic physical conditions are at increased risk for an inactive lifestyle, and will contribute to adaptation of patient management accordingly.