Professor Dorothy Dunlop, of Northwestern University, Chicago, who studied nearly 2,000 patients with arthritis in their knees, said: "It is known that the more time people spend in moderate or vigorous activities, the less likely they are to develop disability, Daily Express reported.
The researchers looked at 1,680 people aged 49 to 83, who were free of disability but either had, or were at risk of developing, osteoarthritis in their knees.
Patients wore an accelerometer around their hips to check their daily activity levels, and as expected, people engaging in moderate or vigorous activity had less disability two years later.
However, the team also found that people who did light physical activity also had fewer disabilities.
The research has been published in the British Medical Journal.