Fig. 1.

Schematic representation of ageing trajectories and individual exercise needs. Good physiological function is maintained until middle age and thereafter progressively deteriorates. The upper horizontal dashed line represents a theoretical point at which deterioration manifests as moderate functional deficits and above this line the general aim of physical activity is to maintain good health. The lower horizontal dashed line indicates a theoretical threshold beyond which a person suffers disability and frailty, so the aim of physical activity is to recover the deficits and improve mobility. The curved lines represent a accelerated ageing, b normal ageing and c healthy ageing. Exercise interventions should match the physical capability, rather than chronological age per se to be effective