The multidomain mobility lab in older persons: from bench to bedside. The assessment of body composition in older persons at risk of mobility limitations.

With body composition it is possible to divide human body in compartments on the basis of different physical properties. The two level body composition model subdividing the whole body in fat mass and fat free mass is the most used in epidemiological and clinical studies in the elderly. Body composition techniques may be used to study ageing process. Changes in body composition occur as part of the normal ageing process and are associated with important effects on health and function. It has been shown that body composition changes with aging, with an increase in fat mass and a decrease in muscle mass, have important consequences on health and physical disability. Moreover body fat distribution changes with adverse metabolic profiles and increased cardiovascular risk. The purpose of this review is to describe the basic principles and techniques for fat free mass and fat mass evaluation, highlighting the advantages and limitations of different available body composition methods.