Jogging not a knee-killer, study says

In next month's Skeletal Radiology, a team of Austrian radiologists presents knee MRIs of seven runners who had taken part in a previous MRI study before running the Vienna marathon in 1997. The use of MRIs offers a significant diagnostic advantage compared to earlier studies that relied on X-rays.

The results were clear: no new damage in the knee joints of the six subjects who had continued running in the intervening decade. "In contrast, the only person who had given up long-distance running showed severe deterioration in the intra-articular structures of his knee," the authors note.

An even more long-term study at Stanford University has been following 45 runners and 53 non-runners since 1984. All had been taking regular X-rays. The latest results, which will appear in a future edition of the American Journal of Preventive Medicine, show that after 18 years, 20 per cent of the runners had developed osteoarthritis in the knee, compared with 32 per cent of non-runners.

These studies raise a possibility that several earlier studies have proposed: Running may help preserve the joints. But that's not a conclusion that can be drawn at this point, says Eliza Chakravarty, lead author of the Stanford study.

One drawback with both studies is selection bias. The runners in both cases were committed recreational runners who had a history of being able to run without serious problems.

Of course, the decision doesn't have to be strictly utilitarian. As one of the Vienna study participants (who was preparing to run his 37th marathon) put it in a recent e-mail to lead author Wolfgang Krampla, "Even if minor aches and pains occur over the years, the gain in joie de vivre far outweighs them."