Knees Work Better in Water – New Study

21 November 2007

Water exercise can benefit anyone, as water’s buoyancy accommodates both the fit and the unfit, and you’ll burn more calories with less joint wear than you would exercising on land.

The study, which appears in the October 2007 issue of The Cochrane Library, analysed six trials with a collective 800 participants with osteoarthritis. Four studies included patients with OA of either the knee or hip, one study followed patients with only hip OA and one included patients with only knee OA.

In the studies, some patients did aquatic exercises for different lengths of time and numbers of sessions per week, while others did no exercise or exercised on land. Most of the studies measured patients after three months of therapy.

Less Pain and Better Movement
The aquatic therapy participants reported significantly less pain and significantly superior physical function on many secondary outcomes. Hip muscle strength and quality of life also were significantly greater in this group than in the control group at 6 weeks.

One randomized controlled trial that evaluated the efficacy of water therapy for hip and knee arthritis showed that a 6-week, twice-weekly program leads to reduced pain and joint stiffness as well as improved physical function, hip muscle strength, and quality of life in people with OA.

The benefits of water therapy appear to remain 6 weeks after the cessation of the supervised program, and participants were found to enjoy programmes so much they continued with them after the trial ended.

Who Can Benefit From Water Exercise?
Age and physical condition aren't issues in the water. Seniors who rely on a walker or wheelchair on land can stand in water with the help of flotation belts and water's buoyancy.

Health benefits found in various studies include:
• Increased muscle strength
• Enhanced sense of wellbeing, mood and sleep quality
• Decreased fear of general exercise
• Improved oxygen intake
• Greater flexibility
• Loss of excess body fat
• Increased agility
• No exercise-related injuries
Why Water Exercise is Good for Arthritis
Water's buoyancy accommodates both the fit and unfit. Water cushions stiff and painful joints or fragile bones that might be injured by the impact of land exercises. When immersed to the waist, your body bears just 50% of its weight; immersed to the chest, it's 25%-35%; and to the neck, 10%. The lower gravity promotes the return of blood to the heart from the extremities.
Water provides at least 12 times greater resistance than air, and in every direction. Water cools your body and prevents overheating. But even in 80- to 85-degree water, the recommended temperature for exercise, you should warm up in the water before your workout to prevent injury. Just as with a land workout, you will sweat during water exercises, so it's important to drink water.
Also, studies of water walking have showed that the number of calories burned increases with the depth of the water. A half-hour of deep-water running burns 300 calories, compared with 200-250 for running on land, 150 for tennis, and 150-200 for aerobics. Also, a 150-pound person swimming at his or her target heart rate burns about 600 calories per hour.
Knee arthritis currently affects about 40% of people aged over 75 years, and hip OA affects about 10%. People with osteoarthritis frequently report joint pain, stiffness, loss of physical function, increasing immobility, and muscle weakness.

What Type of Water Exercise?
There are a wide range of warm water exercises to choose from, including:
• Specialised arthritis exercise programmes - check with your local fitness centres or arthritis organisations for what is available in your area.
• Hydrotherapy – a type of exercise therapy offered by physiotherapists. Classes may offer group sessions or one-on-one training. The water for hydrotherapy sessions is usually heated to around 34°C.
• Gentle water exercise – some fitness or recreation centres offer gentle water exercise programs for people who are elderly, disabled or unfit.
• Gentle aquarobics – some fitness or recreation centres offer water exercise classes that aim to improve general fitness. Because aquarobics exercises can be more vigorous than hydrotherapy, the water is usually heated to around 28°C.
Before You Join a Class
Always check with your doctor before starting any new exercise program. For example, you may need to avoid certain movements if you have had joint replacement surgery.
• Contact the various fitness and recreation centres in your local area to find out what sorts of warm water classes are on offer.
• Think carefully about the venue. Public swimming pools, for example, generally have cooler water temperatures, which means you could feel cold while exercising.
• Assess the venue. For example, is the pool easy to access? Are the change rooms accessible and comfortable?
• Before choosing a class, make sure it is appropriate to your level of fitness and ability. You may like to watch a class or two from the sidelines.
Safety suggestions
Once at the pool, safety suggestions include:
• Be guided by your instructor, but a good way to warm up is to swim gently or go for a ‘walk’ through the water.
• It will take time to build up your fitness, so aim for no more than 20 minutes of exercise at first.
• If you are exercising in a hot spa, get out after seven minutes or so.
• If you feel light-headed, sick or dizzy at any stage, get out of the water.
• Take care when moving in wet areas around the pool, including in change rooms, to avoid slipping and falls.
• Don’t try to do too much too soon. If you feel out of breath, slow down.
• Perform each movement as gracefully and smoothly as you can.
• Keep the body part you are exercising under the water. This may require you to squat or bob down at times.
• If a movement causes pain or discomfort, stop immediately.
• Drink plenty of fluids during and after exercising.
• Rest for a while once you get home.
• If you have painful joints or sore muscles for more than a few hours after your class, try to go a little slower next time.
Warm water exercise at home
You may like to perform water exercises at home if you have a swimming pool or spa. Suggestions include:
• Check with your doctor if you have particular medical problems – such as heart disease, low blood pressure or diabetes – before you do any exercises in hot water (such as a spa).
• Follow the routine outlined in your class or consult with a physiotherapist for an individually tailored program.
• If you are unfit, a poor swimmer or have difficulties climbing in and out of the pool or spa, only exercise when someone else is home.
• Make sure the water is comfortably warm, but not hot.
• Do not stay in a hot spa for longer than 20 minutes.
• Use the jet nozzles in your spa for massage therapy.

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