Measuring physical capacity and performance in older people.
Lamb SE., Keene DJ.
We highlight the important differences between the concepts of capacity and performance and highlight the development of measures and their application in common conditions encountered in health care practice with older people. A number of expert consensus projects have concluded that mobility, balance, muscle strength and dexterity are core domains for capacity measurement in older people. Instruments with evidence of adequate psychometric properties for the evaluation of capacity in response to intervention programmes include the Short Physical Performance Battery, hand grip strength, mini-BEST and 9-hole pegboard test. Measures that can track individual change and convey information that can be used to inform clinical decision-making, individual prognosis or prediction of events require greater precision. However, few such measures are available. Performance measurement usually focuses on basic or instrumental (advanced) Activities of Daily Living performed by people in their usual environments. Finally, we discuss the limitations of physical performance and capacity measures and future developments that may enhance the use of these measures in health and clinical care.