Dimensions of mobility: Defining the complexity and difficulty associated with community mobility

Mobility, the ability to move independently, is critical to maintaining ind ependence and quality of life. Among older adults, mobility disability resu lts when an individual cannot meet the demands of the environment. Current approaches to defining mobility rely on distance and time measures, or deco mpose mobility into subtasks (e.g., climbing, sit to stand), but provide li mited understanding of mobility in the elderly. In this paper, a new concep tual framework identifies the critical environmental factors, or dimensions , that operationally define mobility within a given community, such as ambi ent conditions (light levels, weather conditions) and terrain characteristi cs (stairs, curbs). Our premise is that the environment and the individual conjointly determine mobility disability. Mobility in the elderly is define d not by the number of tasks a person can or cannot perform, but by the ran ge of environmental contexts in which tasks can be safely carried out: the more disabled, the more restrictive the dimensions.