The Role of Sports and Activity in Osteoarthritis:

Record numbers of children are now members of their school soccer team, youth basketball leagues or summer tennis programs. For many, these activities do not end in elementary school but continue into their teenage years and beyond.  While activity is excellent for maintaining a healthy body, and moderate activity appears to decrease the risk of developing osteoarthritis, there is some new research that suggests certain types of particularly high level athletic activity, particularly in young adults, may actually increase the risk of osteoarthritis, a painful and damaging joint disease.

Osteoarthritis is by far the most prevalent forms of arthritis. In U.S. adults over the age of 30, osteoarthritis of the knee occurs in 6% of individuals and osteoarthritis of the hip joint in 3%[i]. Osteoarthritis is one of the more common reasons that people complain of problems walking and climbing stairs and it is estimated to produce a cost of 2% of GDP in lost work time and early retirement.

Osteoarthritis is characterized by a progressive loss of cartilage that is often accompanied by the development of bone cysts and growths that reduce joint motion and can produce pain. There are certain risk factors for osteoarthritis such as abnormal joint anatomy, high body weight, joint surgery[ii] and, surprisingly, playing certain sports. Doctors tout the benefits of moderate exercise for all healthy individuals, but new research suggests that playing certain sports at particularly high levels of competition may lead to an increased risk for osteoarthritis later in life.

The risk is greatest for athletes categorized as “elite.” Elite athletes are commonly defined as those who participate professionally or on an internationally competitive level. The prevalence of osteoarthritis in elite athletes is higher than in non athletes with 3.3% of elite athletes affected in comparison to 1.4% in non athletes[iii]. Elite athletes tend to specialize in one sport; if the sport is one of particularly high impact or strain, these negative effects can be magnified. The negative effects of playing elite high impact sports are also extremely pronounced for women: women who exercised at these levels as teenagers were at greater risk for moderate to severe hip osteoarthritis.

Certain sports are thought to have a low risk for osteoarthritis, such as cross country skiing, walking and swimming. In contrast, soccer players, football players, rugby players, weight lifters, runners and tennis players incur a slightly higher risk.

Soccer is one of the fastest growing sports for adolescents. With more and more children participating in soccer leagues, and the abundance of professional soccer leagues and elite soccer athletes, examining the relation between soccer and osteoarthritis has far reaching implications. Osteoarthritis is one of the most common injuries in this group: reports estimate that almost 30% of elite soccer players show evidence of osteoarthritis. This occurrence of osteoarthritis is a major reason why many professional soccer players retire: 58% retire because of injury relating to osteoarthritis. The relatively high rate of injury in soccer, particularly knee and ankle injuries, largely contributes to this high risk because osteoarthritis is much more common after joint surgery and acute impact.  Essentially, any acute trauma to a joint can potentially start a cascade of events in the joint that lead to cartilage destruction and osteoarthritis.

Running is one of the easiest forms of exercise; all it requires is a good pair of sneakers and the willingness to explore your neighborhood. It also appeals to all kinds of people and with a wide range of abilities: the sprinter, the slow and steady marathoner or the mid-distance runner. In comparison to soccer, running is advantageous on the joints because it is not a contact sport and has a lower rate of acute injuries and impacts. Running may lead to more chronic ailments. The development of osteoarthritis in elite runners has been linked to both the amount and rate of mileage run[iv]. The choice of terrain and a person’s running form and footwear may also affect the risk for osteoarthritis.  Elite runners tend to have osteoarthritis in their hips, in contrast to soccer players who are mainly affected in their knees and ankles where they are more likely to suffer an acute trauma from a collision, slide, twist, or tackle.

Sports that encourage a high body mass such as weight lifting and football linemen, often incur an increased risk for osteoarthritis, likely because of the increased stress posed on their joints. Similarly, an obese individual is at a greater risk of developing osteoarthritis.

Not everyone is a David Beckham or a Marion Jones. Many people pursue exercise on a more recreational, moderate level, and they may pursue not one sport, but several. The advice to receive a physical exam before beginning a new exercise program should always be heeded. A sport-specific exam might also be beneficial as certain sports depend on certain muscle groups that may be undeveloped. Quadriceps weakness, for example, is commonly found in patients with osteoarthritis. Many sports depend on the strength of this muscle, and so a weakness might produce a higher risk for injury.

While elite levels of exercise seem to produce an increased threat of developing osteoarthritis, recreational exercise on a more moderate level can be not only safe, but beneficial in reducing the risk for osteoarthritis. Recreational physical activity is also associated with a lower risk of suffering osteoarthritis of the knee requiring total knee arthroplasty[v].

For many people, their occupation involves some degree of exercise or joint stress. Good news for all the hard working men and women is that physical occupational exertion does not appear to increase the risk for osteoarthritis of the knee[vi]. Similarly, physical education teachers who typically exert a moderate level of activity were in fact found to have lower rates of knee osteoarthritis than in the general population[vii].

Recreational activity thus does not appear to pose the potential physical threat that elite, high level sports playing can in terms of developing osteoarthritis. Moderate levels of exercise in rats has been shown to reduce the risk for osteoarthritis[viii]. In addition, there are two aspects of sports that affect its potential in triggering osteoarthritis: acute injuries, and chronic joint stress. Sports such as soccer pose a high risk for injury which can cause a higher risk of osteoarthritis. Thus, injury prevention, and treatment of existing injuries is a critical factor in reducing the chance for developing osteoarthritis. The chronic stress experienced by many long distance elite runners and athletes is not an issue for most recreational athletes and they can reduce their risks of developing osteoarthritis by taking a day off when sore, and seeing a doctor at the first sign of injury or pain.

While playing sports and physical activity appear to in some cases have negative consequences on health, the other benefits of athletics typically far outweigh the risks in many cases. Athletes tend to have lower pain sensitivities than non-athletes, and exercise is associated with higher life expectancy, and lower risks of heart disease and diabetes[ix].

            For those who already have osteoarthritis, can exercise help?  Moderate exercise in patients with osteoarthritis is essential.  Indeed, research shows that moderate exercise in patients with or without osteoarthritis can have many beneficial effects.  Of course, always speak with your doctor before starting any new exercise regimen.  Exercise can improve strength, stability and endurance. However, research also shows that many people do not continue their exercise plans, and often cease activity after 18 months[x]. With the consultation of a doctor, patients should continue with a moderate level of activity to the degree that their pain and disease permits.  A general guideline is that weight-bearing activity is important to maintain healthy bones; however impact activities may need to be altered to reduce the stress they pose on joints.

            The relationship of sports activity and the development of osteoarthritis is complex, but research shows that moderate exercise with the consultation of a doctor, and taking proper care of acute and chronic injuries may avert or lessen the development, severity and progression of osteoarthritis.  Certainly, this article does not suggest or recommend that you take your children off their soccer team or other sport team.  But it is important that you talk with an arthritis doctor to identify your child’s, as well as your own, individual risk factors so you can take the proper steps to reduce them.  Elite athletes should be aware that certain aspects of their sport may predispose them to a slightly higher risk of osteoarthritis development.  These athletes should make a special point to speak with a doctor who specializes in arthritis so that they can learn to take steps to reduce their risk.  Steps to take may include supplementation with glucosamine and chondroitin sulfate and other supplements, a specialized anti-arthritis diet, and exercises that focus on strengthening and stretching certain specific key muscle groups depending on the sport and specific risk factors.

Authors: Abigail E.L. Chambers, Princeton University, Princeton, NJ

               Grant Cooper, M.D., New York-Presbyterian Hospital, The University Hospital of Columbia and Cornell, New York, NY