Exercise as it relates to Disease/Effects of resistance training on Osteoarthritis

What is Osteoarthritis
Osteoarthritis (OA) is the most common form of arthritis. It is a degenerative condition that commonly affects the hands and spine, as well as joints such as the knee, ankle and hips. Degeneration occurs in the cartilage that covers the ends of the bone. This cartilage usually helps with shock absorption and allows bone to glide smoothly over one another, however in sufferers of OA, this cartilage breaks down and wears away, causing the bone to rub together.

Prevalence
OA affects millions of people worldwide and is most common in females, people who are overweight and the likelihood also increases in old age. The number of people affected is likely to increase due to an ageing population, as well as the obesity epidemic. Other common factors include previous injuries to the joint, high impact exercise, body density and muscle weakness. OA is also the leading cause for knee and hip replacement surgery.

Signs and symptoms
The severity of symptoms can range from mild to severe, depending on the individual, as well as which joints are affected. Common signs include: All of these symptoms can affect simple, daily activity, including walking, standing up and even opening a jar.
 * joint pain and stiffness
 * inflammation of the tissues around the joint
 * visible deformaties
 * reduced range of motion
 * proprioception deficits

Benefits
Two of the main causes of OA are excess body fat and muscle weakness. Exercise is crucial in minimising the risk of obesity by reducing body fat and maintaining weight, while resistance training is important to increase muscle strength as well as joint range of motion and stability. A decrease in muscle size and function can directly affect a patients mobility and functionality. For example, a sufferer of knee OA often experiences a gradual decline in knee muscle strength (quadriceps), which directly affects walking speed and functional performance. By improving muscle strength around the knee, a patient may see an improvement in walking ability and speed, reduced pain as well as increased function of the lower extremities. Elderly sufferers will see the most considerable benefits from resistance training since muscle strength and mobility significantly declines as we age. One study found that the muscle mass of 80 year olds was 40% less than that of people in their twenties. Muscle strengthening can lessen the risk of falls in the elderly and improve quality of life.

Precautions
Exercise pre-screening is recommended for anyone who is considering undertaking a new exercise regime. It is also important to note that exercise is individual, and varies from patient to patient. Previous research suggests that exercise should not include high joint loading. If the joint is overloaded, patients with OA may aggravate symptoms such as pain, swelling and inflammation. This is commonly seen is patients with knee OA. High impact exercise is considered a trigger and should be closely monitored, or in some cases avoided completely.

Prescription
It has been shown that both high and low-intensity resistance training have equally positive outcomes on muscle strength and function. In some cases high-resistance training has been shown to be more beneficial. When looking at dynamic training, where the joint is put through its entire range of motion vs isometric resistance training, where the joint does not move as muscle tension is generated, studies have shown that both are equally beneficial for improving muscle function and pain. It is important to start slow and do what is comfortable. Training with a partner is great for motivation as well as safety. Stretching before and after resistance training is strongly encouraged to increase flexibility and range of motion as well as decrease muscle soreness. If any pain is experienced, training should cease immediately and a health professional should be consulted before further training occurs.

Recommendations
By following the F.I.T.T principle we can establish some rough guidelines for resistance training for OA sufferers.