Middle-aged people who like to stay in shape with strenuous exercise such as running could be doing themselves more harm than good.
They are damaging their knee joints, and they are also increasing their chances of developing osteoarthritis, a new study has discovered.
Researchers have been monitoring the health of 236 people - 136 women and 100 men - aged between 45 and 55, who exercised to some extent. Those who strenuously exercised by running or jumping on a frequent, almost daily, basis had far more damage to their cartilage than those who did low-impact exercise such as cycling or swimming.
(Source: Radiological Society of North America annual meeting, December 1, 2009).