Debunking jogging myths

Knees rejoice, running may not be so bad for the joints after all

BY JILL BARKER, CANWEST NEWS SERVICE MARCH 3, 2010COMMENTS (14)

More and more research points to exercise being good for your knees. And in some cases, exercise is just what the doctor ordered to get rid of persistent knee pain.

Photograph by: Photos.com, canada.com

If you're a runner, chances are you've been told that years of hitting the pavement are tough on the knees. And for fitness fanatics with sore knees, rest -- not more exercise -- is usually recommended for a speedy recovery.

Turns out both suggestions are outdated. More and more research points to exercise being good for your knees. And in some cases, exercise is just what the doctor ordered to get rid of persistent knee pain.

Stanford University researchers tracked the knee health of 98 runners and non-runners between 1984 and 2002. Imaging scans comparing the joint at the start and end of the study revealed that runners' knees were no worse for wear than those of non-runners.

Also good to know is that the amount of mileage runners accumulate isn't a factor in knee pain. A long-term study (subjects were followed for 40 years) noted no difference in the knee health of runners who logged 40 miles a week vs. those who ran 20 miles a week.

Another study compared the knees of runners to those of swimmers. No difference was reported in the level of knee pain between the two groups of athletes, despite the difference in weight bearing and impact stress of the two sports.

Even in the short term, running seems to have little negative effect on the knee. MRIs taken before and after a marathon revealed no severe damage in the cartilage, ligaments or bone marrow of knees following the 42-kilometre run.

What's even more exciting than finding out that running doesn't injure or prematurely age the knees is that pounding the pavement may actually improve knee health.

Science Daily reported on a Dutch study that looked at two groups of knee pain sufferers. One took part in a supervised exercise program as part of rehabilitation, while the other received a sheet of standard exercises to be done alone at home.

In examinations three months and 12 months into the study, the supervised group of exercisers reported a greater reduction in joint pain and a greater degree of improved function when compared to subjects in the control group.

If that's not enough good news, there's even a school of thought that suggests running actually conditions the cartilage, making it more resilient and less prone to the stress of everyday activity.

Before you go around bragging that athletes' knees are stronger than knees of the average couch potato, you may want to note that not all exercise is knee-friendly. Soccer players, alpine skiers and football players all have a higher-than-normal incidence of osteoarthritis, a thinning of the joint cartilage that causes the bone surfaces to rub against each other.

The high incidence of knee injury in contact sports is the reason why some athletes are more prone to osteoarthritis later in life. Sports that expose the knee to impact and those that demand quick cuts (changes in direction) are hard on the knees. Cartilage and ligament tears are common in these types of sports. It's also common for elite athletes to experience more than one knee injury during their competitive careers.

That kind of trauma is proving to be more invasive than initially thought. Cell damage to the tissue around the knee extends far beyond the torn ligament or cartilage and may take longer to heal than current conservative estimates suggest. Injuries also affect the movement pattern of the knee, which can place undue stress on the cartilage and speed its degeneration.

By all counts, exercise is important in rehabilitating injured knees, but also in reducing the risk of injury. Strong leg muscles, including the small stabilizing muscles of the knee and hip, can withstand more physical stress than weaker legs. This in turn protects the vulnerable knee. Time in the weight room and sport-specific exercises geared to protecting the knee are investments in long-term health.

So is running, which is great news for runners who have been subjected to years of suggestion that their habit is going to ruin their knees one day. It's also good news for those who want to take up running later in life. Healthy older adults who follow a supervised training program that progresses gradually in intensity and distance are at no risk of long- or short-term knee injury.

In fact, the argument could be made that taking up running or fitness walking later in life is protective of the knees. Joints, like muscles, are built to move. And movement brings with it strength, not weakness.

As for runners who are ignoring knee pain, don't consider these studies as an excuse not to have your knee checked by a sports medicine professional. Most knee pain is short term and conducive to treatment. And in case you're worried, not all treatment plans call for you to give up your running habit, even temporarily. Knees are precious, so exercise them wisely.