The level of fitness and skill we've witnessed at the World Cup this past month has been incredible. Even though the players make it seem effortless, they have paid for the privilege of playing in the tournament with endless punishing training. More specifically, their knee and hip joints have been put under incredible pressure, year in and year out. For many elite sports people this dedication can lead them to arthritis later in life. World-class athletes are supposed to have tough, strong bodies; however, some recent studies have shown former top athletes actually have a higher incident of arthritis than non-athletes. Two examples are Carl Lewis (winner of nine Olympic gold medals in track and field) and Bart Connor (winner of two Olympic golds in gymnastics). One of the more common forms of arthritis is osteoarthritis, or degenerative joint disease. The main cause is a loss of cartilage, resulting in bone spurs and cysts. Usually it occurs in weight-bearing joints such as hips and knees. Cartilage and bone are further damaged when bones rub together. Losing a lot of cartilage leads to great pain and makes movement difficult. There are either primary or secondary causes of osteoarthritis. Primary osteoarthritis is commonly linked to old age when the cartilage naturally breaks down due to wear and tear. Secondary osteoarthritis - what most elite athletes suffer from - is caused by chronic or sudden injury to a joint. Sports don't necessarily predispose an athlete to arthritis. Dr Christopher Harner, a professor of orthopedic surgery, and Dr D Kelly Agnew, an orthopedic surgeon, both from the United States, believe osteoarthritis is not an inevitable by-product of sport. Harner even believes a traumatic injury, such as a broken leg or torn knee ligament, shouldn't doom the young athlete to arthritis provided the initial treatment is done properly and the injury heals correctly. The explanation for the higher incidence of arthritis in former elite athletes is that the intense competitive drive it takes to be a champion causes joint injuries and damages cartilage. Often elite athletes injure their joints in competition and ignore the pain. They train through wear-and-tear injuries and suffer from joint injuries that never heal. In fact an injury isn't the only thing that causes arthritis. Genetics, body habits, the shape of the joint and the way it's formed are all thought to play a part in determining whether or not someone will develop arthritis. Of course, someone who overtrains, especially as a young child, runs a higher risk of suffering from injuries. While researchers aren't sure if a certain type of training leads to later problems, one thing they do know is that the overall health benefits of regular participation far outweigh musculoskeletal injuries. Years ago doctors advised people to avoid exercise in an attempt to save the joint. Today, researchers and doctors believe the stronger the muscles, the less wear and tear on the joints that can then reduce the symptoms of arthritis. So while you may be turned off intense training because of the wear and tear on the joints, researchers have found it's not the case for recreational exercisers. A few general guidelines include alternating intense days with rest, and stopping when you feel any pain. Be sure to use proper technique and if in doubt seek the help of a qualified instructor. Avoid high-impact activities. Good examples of exercises that are easy on the joints include water exercise, stationary bikes, strength training with resistance tools such as elastic bands and free weights, tai chi and yoga. The research coming out today clearly points to exercise as one of the best ways to keep joints in working order and even prevent further damage.