Exercise as it relates to Disease/Physical Activity intervention as a treatment for Osteoarthritis

What is Osteoarthritis
Osteoarthritis (OA) is the most common chronic arthritis often referred to as 'wear and tear arthritis' due to it's progressive degenerative nature. OA can be viewed as the clinical and pathological outcome of a range of disorders that result in structural and functional failure of synovial joints with loss and erosion of cartilage, Subchondal bone alteration, degeneration, a synovial inflammatory response and cartilage overgrowth (osterphytes''). The predominant symptoms are pain, a decreased joint range of motion (ROM) and stiffness, periarticular muscle weakness and atropty, joint effusion and swelling, and physical disability. OA can occur in any synovial joint in the body but is most common in the knees, hips and hands. There is currently no cure for OA and treatment modalities have focused on pain relief and preservation of joint function.

Causes
OA occurs when the dynamic equalibrum between the breakdown and repair of joint tissues falls out of balanced. The major risk factors that contribute to the cause of OA are obesity, genetic inheritance, physical inactivity, joint trauma and injury (Mostly mechanical stresses ), repetitive joint use (wear and tear) and joint misalignment. Overweight and obese individuals have an increased risk of developing OA, especially in weight-bearing joints like the knees. Increased wight puts more pressure on joints causing cartilage to deteriorate faster than usual. Jobs involving repetitious physical activity, overworking the joints and the fatiguing of muscles that protect joints tent to increase the risk of OA in the joints used.

Prevalence
Over 1.6 million Australians are estimated to have been diagnosed with osteoarthritis, with the condition being more common among women than men. OA is more prevalent with increasing age, with the average onset being 45 years. OA is the leading cause of disability in older people with around 6% of adults ages over 30 years and 13% of persons ages 60 and over have frequent knee pain and radiographic OA. The prevalence of OA is expected to increase as the population ages and the prevalence of obesity rises. By 2020 it is expected that the number of people with OA may have doubled.

Physical Activity as a Treatment
Physical activity (exercise) may be the most effective, malleable and inexpensive modality available to achieve optimal outcomes for people with osteoarthritis. Physical activity has proved to be integral in achieving therapeutic goals, improving general health, reducing secondary disability, facilitating weight loss, preserving joint range of movement, improve strength, improve functional performance and reducing symptoms. Physical and occupational therapists and doctors prescribe exercise to reduce pain, impairments and improve function. Although further research is needed to investigate and identify the optimal frequency, intensity, time and type of exercise intervention, research has shown that resistance (strength) and aerobic (cardiovascular)exercise provides benefit to those who suffer OA. Implementing both modes of training will help to improve symptoms and reduce comorbidities. The positive changes made with physical activity do not persist if the program is discontinued, thus, the motivation of the patient to start and continuously practice exercise is vitally important. As a basic guide to physical activity, patients should follow the National Physical Activity Guidelines.

Resistance Training
Resistance training improves muscle strength and self-reported measures of pain and physical functioning. Resistance training interventions could take the form of resistance machines, free weights, isometric exercise and other devices such as resistance bands or a combination of methods. Studies have shown a relationship between weaker quadriceps and an increased risk of developing OA, particularly in women, so strength training may be able to prevent and/or help manage knee OA. Recent studies support the assumption that muscle weakness and atrophy contribute to the disease process therefore resistance training should be performed on a regular basis in order to counteract these problems. Low and high intensity resistance training leads to reduced pain and increased functioning, high resistance training yields higher functional performance and greater reduction of pain. Low and high resistance training with or without weight bearing has been shown to have beneficial effects.

Aerobic Training
Aerobic (Cardiovascular) exercise both high and low intensity is beneficial to patients with OA. Aerobic exercise decreases pain, increases muscle function, increase aerobic capacity, decrease depression and anxiety, decrease fatigue and increase muscular strength and flexibility. Aquatic based aerobic exercise has been shown to be less efficient in reducing pain and improving muscle function than land based exercise, however, in cases of severe pain and/or obese patients, an initial period of water-based aerobic exercise is helpful (Buoyancy creates a low-impact environment) the aquatic environment provides a workout without joint loading, which is beneficial as further pain and weight-related joint destruction is avoided.

Recommendations and Considerations
It is recommended to participate in physical activity as a treatment for OA, However certain precautions should be taken to ensure safe progression though any exercise programs.
 * Participate in physical activity at least 3 times per week following national physical activity guidelines.
 * Supervised exercise over non-supervised or at home.
 * Physical activity must be specific and individualized to the person training, there is no one template to follow for the treatment of OA when physical activity is used as an intervention.
 * Pre-exercise medical screening including medical clearance from a Doctor or GP as well as ongoing communication.
 * Take into consideration any co-morbidities a person may have and progress accordingly.
 * Ensure exercise does not elicit too great of a pain response.
 * The use of heat creams or gels before exercise and icing of the affected area/s after exercise.
 * The use of painkillers during the first weeks of an exercise program.
 * Low impact exercise is recommended over high impact.