A commonly cited definition is by Fried:
"a clinical syndrome in which three or more of the following criteria were present: unintentional weight loss (10 lbs in past year), self-reported exhaustion, weakness (grip strength), slow walking speed, and low physical activity" A good clinical pointer is the 'get up and go' test which is often used in geriatric ward rounds to assess a person's mobility and the presence of difficulties that may not be apparent in the history and examination.
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