Could exercise be bad for you?

We all know that keeping fit is good for us. But new research has shown that too much of the wrong exercise can lead to serious problems in later life

Remember school PE teachers, those sweaty, non-smoking, non-drinking, lean-bodied, white-vested muscle machines? One minute impressing wheezing adolescents with their prowess at vaulting horses and climbing wall bars, the next tossing a medicine ball at spotty, bespectacled youths perceived as slackers, they were the pinnacle of fitness and adored by almost all.

Remember school PE teachers, those sweaty, non-smoking, non-drinking, lean-bodied, white-vested muscle machines? One minute impressing wheezing adolescents with their prowess at vaulting horses and climbing wall bars, the next tossing a medicine ball at spotty, bespectacled youths perceived as slackers, they were the pinnacle of fitness and adored by almost all.

But now, it would seem from the evidence of new research, that all the time they were vaulting, running, jumping, squat-thrusting, and impressing 12-year-olds, their bones were slowly crumbling.

While moderate exercise maybe good for the heart and lungs, it's emerging that too much of the wrong kind is bad news for the joints and can lead to a painful middle- and old-age.

A number of research studies are now suggesting that human joints were not meant for too much constant pounding, and that damage even at a young age can lead to osteoporosis in the knees, ankles, hips and neck. Other over-use injuries can also affect the tendons around the ankle, knee, hips, shoulder and wrist.

So serious are the effects of excessive use that almost one-in-six English soccer players who were studied by one team of researchers were so seriously affected in the joints that they are registered disabled.

In the latest research in Sweden, doctors looked at osteoarthritis in more than 500 PE teachers who graduated between 1957 and 1965 and compared their joint health with that of a similar number of men and women chosen at random.

What they found was that both men and women teachers had a higher prevalence of arthritis of the knee. They were also absent from work more often, and the women teachers had to change their jobs more frequently because of knee disorders. Women PE teachers were also up to three times more likely to have arthritis of the hip, and only one-in-five of all the teachers were still in the job at 60.

"The PE teachers were more often subjected to knee surgery, reported more absence from work because of knee disorders, and had to change their work or tasks more often," says a report on the research in the Journal of Occupational and Environmental Health.

The Swedish study is not the first research to suggest a link between exercise and ill health. Doctors at John Hopkins University found that people who suffered knee injuries in their teens or as young adults have a threefold increase in the risk of having arthritis by the age of 65.

Other studies have shown an increased risk of arthritis in middle-aged female ex-athletes, and another reported that long-term weight-bearing sports activities like jogging, squash, hockey, badminton and aerobics are linked to arthritis. Two other Swedish studies have shown that high participation in all kinds of sports increases the risk of arthritis of the hip in both sexes.

In professional sports the risks are even greater. Researchers at the Centre for Hazard and Risk Management at Loughborough University, who measured so-called lost-time injury rates among the players at two Premiership and two First Division soccer clubs over three years found that there were 744 injuries to the players, and at least 86 per cent of players in each of the four clubs had one or more injuries.

"What we found was that the overall level of injury to the professional player was 1,000 times higher than that found in industrial occupations that are more traditionally regarded as high-risk, such as mining and the construction industry," says Dr Colin Fuller, whose research is published in the British Journal of Sports Medicine.

Researchers at Coventry University interviewed a sample of nearly 300 former players and found that 49 per cent had been diagnosed with osteoarthritis, a rate that is five times that in non-sportsmen. One-in-three had undergone surgery of some kind after retiring from the game, and 15 per cent were registered disabled.

Research psychologist, Dr Andy Turner, said, "The people who we looked at were senior players, some internationals. Osteoarthritis is normal associated with old age, but some of these players were getting it in their mid thirties. The average age for the start of symptoms was forty.''

At Sunderland University, consultant surgeon Professor Greg McLatchie, professor of sports medicine, has first-hand experience of the downside of exercise.

"I played a lot of sport. I played rugby and golf to county level, and I was the British universities weightlifting champion. Now I am 50 and I have osteoarthritis of the hip. I can hardly walk 18-holes of golf and my friends laugh at the way I approach the golf ball because I have to shake my left leg because it sometimes gets caught. I am also getting problems with pain and numbness in the arm, probably because of neck problems," he says.

"I do put my injuries down to sport. There is no doubt that sport is good for you, but it can also cause problems. The problems I think lie in overuse. Activity is good, as long as it is within the limits of sense.When I was watching the Olympic Games I was stunned how during the triple jump the whole body of the athlete shudders when one leg hits the ground and the other is airborne. The hips get an enormous jarring.

"Very severe and consistent training is not good. American recommendations are for walking on a regular basis, and maybe we should only jog three miles, three times a week, because five times a week is a strain. I used to run marathons and I am now not so sure that it is a good thing to do. I think it is too far for most people.''

Doctors are keen to point out that moderate exercise is also beneficial, especially for the heart and lungs, and there is also evidence that it improves well-being. Non-load bearing exercise like swimming is also thought to have little adverse effect on joints. Cycling, too, does not have the same pounding affect on the joints as jogging and running.

For the couch potatoes who let the jogging generation pass them by, the bad news is that no exercise at all is more harmful in the long run. Research in America suggests that the health effects of complete inactivity are on a par with smoking 10 cigarettes a day.

And those Swedish PE teachers may no longer be able to touch their toes, climb wall bars or throw medicine balls, but they do have less serious disease and better overall health than the non-athletes.