NewYork-Presbyterian. The University Hospital of Columbia and Cornell.

-- Weight training and cardiovascular exercise may be just the ticket for patients who are preparing for knee- or hip-replacement surgery, a new study published in the journal Arthritis Care and Research suggests.

Those patients who took part in one-hour exercise regimens just three times a week were 73 percent less likely to be discharged to a rehabilitation center after their surgery, researchers found.

While the study is small, study author Daniel Rooks, Ph.D. says, "The benefits of exercise before surgery are very clear. The more you can do for yourself physically before surgery, the better off you are."

Only 12 of 36 patients who took part in the exercise had to enter the rehab centers, compared to 23 of 43 patients who didn't exercise, says Dr. Rooks, an assistant professor of medicine at Harvard Medical School, and Beth Israel Deaconess Medical Center in Boston.

It is no secret that physically fit people are better able to tolerate osteoarthritis, Dr. Rooks says. "Their muscles and soft tissues are stronger and better conditioned, which helps stabilize the knee, protect the joints and allow people with arthritis to move with less discomfort."

Exercise vs. No Exercise Pre-Op Compared

However, it has been unclear how much value exercise provides to people with severe arthritis who face surgery. So, Dr. Rooks and his colleagues enlisted patients who were preparing for either hip- or knee-replacement surgery and divided them into two groups.

One group took part in one-hour group exercise regimens three times a week at a hospital-affiliated fitness center.

At first, participants performed water exercises. Then they moved on to stationary bikes, weight lifting (with both machines and dumbbells) and abdominal strengthening exercises. They also stretched.

"It is not unlike a program that you or I would go through," Dr. Rooks says.

Even in a fairly brief time period - six weeks - the exercise paid benefits for the participants. "We saw that their level of function stabilized and their pain stabilized prior to surgery," Dr. Rooks says. "Those who did not exercise, their function and pain got worse."

Six weeks is not enough time to boost muscle strength by major amounts, says Dr. Rooks. But, he adds, it is possible that some of the benefits came because participants "were just feeling more confident and comfortable that they could exert themselves without hurting themselves."

Ultimately, the study shows that "just because you have arthritis doesn't mean you should not exercise, and if you have arthritis, it's another reason you should begin exercising or keep exercising," Dr. Rooks says.

Weight Training and Knee Arthritis

Another study in the same issue of Arthritis Care and Research examined whether weight training aimed at the quadriceps - the group of muscles along the front of the thigh - could help patients with osteoarthritis in their knees.

Researchers led by Alan Mikesky, Ph.D., a professor at Indiana University's department of physical education, recruited people with knee arthritis and people without it and instructed them to take part in weight-lifting or "range-of-motion" exercises. Of 221 subjects, 174 stayed in the study throughout the entire 30 months.

The researchers found that both groups lost strength in their legs, a finding that was "difficult to explain," but the loss was slower in those who lifted weights, the researchers say.

Also, those with arthritis did not report any decrease in knee pain, and there were conflicting reports about whether weight training might do something positive by helping prevent the narrowing of space between joints.

The researchers are calling for more studies to clarify matters.

Still, other recent research has suggested that exercise can reduce disability in people with arthritis, says Dorothy Dunlop, Ph.D., research associate professor at Northwestern University's Institute for Healthcare Research.

"In addition, physical activity has broad health benefits: It improves endurance, reduces depression and is linked to reduced premature mortality," she says.

Even so, a 2001 federal survey found that 24 percent of arthritis patients took part in no moderate-intensity physical activity, Dr. Dunlop says.

"The Arthritis Foundation and the Centers for Disease Control [and Prevention (CDC)] have designed programs that provide safe and beneficial physical activities for persons with arthritis," she says.

"The opportunities are there. The benefits of physical activity are real. The consequences of inactivity are serious. It is time for persons with arthritis to get moving," Dr. Dunlop adds.

Always consult your physician for more information.