Hydrotherapy Improves Function in Patients with Osteoarthritis
December 04, 2003
By Stephanie Riesenman for Knee1
In one of the most thorough studies to date on exercise therapy for osteoarthritis, researchers in Australia have found that patients engaged in hydrotherapy improve their strength and physical function. Their findings also suggest a more rigorous workout—including weight training—could offer an even greater benefit to patients with osteoarthritis of the hip or knee.
It is well established that muscle strength is an influential factor in the development and progression of osteoarthritis. Decreased strength is associated with increased disability, more time in the hospital, less joint stability, and exacerbation of pain. To date, the effects of swimming pool-based exercise on strengthening of the muscles surrounding arthritic joints has been inconclusive.
"To our knowledge, this is the first study to have directly compared these two exercise modalities (weight training and hydrotherapy) with such methodological quality," said Amanda Foley, an accredited exercise physiologist at Repatriation General Hospital in South Australia. Foley is the lead author of the study published in the November 24th issue of the British Medical Journal.
The researchers enrolled 105 patients, about half were women, over the age of 50 who had either hip or knee arthritis or both. Patients were randomly assigned to hydrotherapy exercise, weight training, or no exercise for six weeks.
Hydrotherapy participants attended classes 3 times a week for 30 minutes. They started with a warm up that consisted of walking forwards, backwards and sideways in a pool. The strength-training portion included hip flexion and extension, hip adduction and abduction, knee flexion and extension, and knee cycling. Over the 6 weeks, the participants worked up to adding weights around their ankles for additional resistance during their exercises.
The gym-based exercise group warmed up on a stationary bike for 4 minutes. Strength training involved the use of weights for the seated bench press, hip adduction and abduction, knee extension, and double leg press. Participants increased the intensity of the routine over the 6-week sessions. The gym-based patients also attended 30-minute classes 3 times a week.
The control group was telephoned after every exercise session — though they did not attend classes — to record any changes in their arthritis. The researchers were nice enough to offer free exercise classes to the control group after the study was completed.
Using a hydraulic leg extension machine the researchers found that both right and left leg strength had increased in the gym-based workout group after six weeks. The hydrotherapy group showed increased strength in the left leg only.
"The gain in strength in the hydrotherapy group was of less magnitude than observed in the gym group," said Foley, "suggesting that there may be some effect of the water resistance on muscle strength, but being so small, it was by chance that is was detected on only one side."
Walking speed and distance improved in both the gym-based and hydrotherapy exercisers, but there was no change in the control group after six weeks.
In a survey, the gym group said they were more satisfied, had better function, and felt less pain after the six weeks. In a different survey, the hydrotherapy group reported higher physical and emotional quality of life following the exercise classes. There was no change in the control group.
The intensity of the exercise in this study was higher than the American Geriatrics Society recommends for strength training in patients with osteoarthritis. But Foley said their results suggest that more intense training can be performed by these patients without exacerbating pain and other arthritis symptoms.
"The more intense the strength training, the greater the stimulus for muscle growth and adaptation," said Foley, "and therefore the results or gains will be greater and likely to be achieved faster."
She also pointed out that the 6 weeks was designed for study, and that all exercise regimens should be taken up indefinitely. Foley made the following recommendations for patients with osteoarthritis who are interested in starting an exercise routine:
Hydrotherapy is good for those who find it too painful to exercise on land.
It’s good for those who are very weak to start off their exercise therapy in a pool before moving on to more challenging programs.
Hydrotherapy is a great form of low impact cardiovascular exercise.
This is recommended for muscle strengthening which is important for joint stability, shock absorbing capacity, slowing disease progression, and for improving surgical outcomes.