Mobility Decline in Old Age

Merja Rantakokko; Minna Mänty; Taina Rantanen


Exerc Sport Sci Rev. 2013;41(1):19-25. 

In This Article

Progression of Mobility Decline in Theory

A widely recognized theoretical model explaining mobility decline in epidemiological studies is the disablement process model by Nagi,[17] later expanded by Verbrugge and Jette,[36] which shows the disablement process pathway from pathology to disability. Pathology, referring to physiological abnormalities, such as chronic diseases or injury, and also to physiological changes with advancing age, affects specific body systems and may result in impairments such as decreased muscle strength and balance or sensory impairments. These impairments usually lead to functional limitations, which in turn finally may cause disability. In the disablement model, mobility usually is considered to belong in the category of functional limitations. Disability refers to a situation where individual capabilities are not sufficient to meet the requirements posed by the living environment. The disablement process model outlines intraindividual and extraindividual factors that can either reduce or increase functional limitations. Whereas the main pathway emphasizes the physiological process, intraindividual factors focus on lifestyle and behavioral changes, psychosocial attributes and coping, and activity accommodations. Extraindividual factors include factors such as the built and physical and social environment. In addition, different predisposing risk factors, such as certain demographic, social, lifestyle, and behavioral characteristics of an individual, may have a direct or indirect effect on the development of functional limitations.

Environmental gerontology studies the relationship between aging people and their physical and social environment and how these relationships shape health, functioning, and quality of life in old age. The widely accepted ecological model of aging, also known as the "competence-press model",[9] describes the person-environment relationship. Among older people, environmental factors, such as hills or long distances to services, may operate as barriers to mobility or as an opportunity to maintain mobility. The effect of environmental factors on mobility depends on the interaction between the environment and the individual and is called person-environment fit. If individual competence and the demands of the environment are in balance, a person is able to function optimally. When this balance is lost and person-environment misfit occurs, difficulties emerge.[9]

There are similarities between the ecological model of aging and the disablement process model. The person-environment perspective of the disablement process model emphasizes that the environment and the individual are of equal importance in the disability process. The environment is seen on the "demand" side and the person on the "(cap)ability" side of the model, as in the ecological model of aging. Both theories emphasize that disability occurs when there is a misfit between the environment and the individual. In both models, a challenging environment is seen as either a threat or as an opportunity to maintain functional capacity.

Although these two theories share a similar content, there are a few differences between them. The disablement process model shows the pathway from pathology to disability, seeking to outline the underlying physiological changes and contributing factors, whereas the ecological model of aging shows the interplay between the individual and the environment from a general perspective and sees the relationship as a dynamic process, explaining the mechanisms behind the interaction. The ecological model of aging has a strong psychological emphasis, whereas the disablement process model emphasizes physiological changes. Combining the salient aspects of these two models into an analytical approach may provide a good foundation to better understand the progression of mobility decline.