Should I exercise for knee Osteoarthritis?
It’s estimated that roughly 30-40% of people will experience knee osteoarthritis as they age with a higher proportion affected being women.
Although there are many treatment options available for treating knee osteoarthritis, early intervention of non-invasive, exercise based treatment can lead to improved quality of life, reduced pain & disability and may even prevent knee osteoarthritis altogether.
Osteoarthritis of the knee is one of the most common clinical diagnoses that we deal with virtually every day in our clinic. Knee Osteoarthritis can cause extreme pain, loss of strength & function and if left untreated can result in surgery later in life. As Osteoarthritis is often a “wear & tear” condition, it could be deduced that treatment targeting reducing the amount of “wear & tear” via an appropriate treatment intervention could prevent or improve the quality of life for those who are at risk or suffering with knee osteoarthritis.
Overweight/Obesity – Carrying extra weight will increase the amount of force loaded on the knee during daily activities. Being overweight is also often an indicator of a lack of physical fitness & strength, which can also contribute to knee osteoarthritis.
Previous Knee Injury – Those who suffered a serious knee injury or incident earlier in life can also be at an increased risk of knee osteoarthritis.
Poor Lower Limb Strength – Weak muscles acting on the knee & hip joint can lead to improper mechanics which, over time, can result in the “wear & tear” that eventually leads to arthritis.
Tight Lower Limb Muscles – Poor flexibility in muscles that act on the knee & hip can result in reduced joint space, which can lead to increased friction and loss of cartilage resulting in osteoarthritis of the knee.
Physical Inactivity – Those who remain inactive for prolonged periods of time can experience muscle loss and weakness, which results in damage when the joint is called into action (e.g. going up the stairs).
Chronic Knee Pain – Most people will experience some form of knee pain in their lives. Chronic knee pain can indicate the presence of other risk factors that can eventually lead to knee osteoarthritis if not appropriately managed.
Overuse of the Knee – Labourers and those with professions involving persistent knee bending/loading are also at increased risk of knee arthritis.
Quadriceps – Strengthening the quadriceps will help keep the load on the muscle during movements. Without enough strength to support the body weight, the knee will experience heightened force and friction aggravating the osteoarthritis mechanism
Gluteus Medius – One of the most important muscles for hip stability and regulating weight transfer during walking. Glute Medius is often weak and under active in people suffering with knee osteoarthritis and therefore forms an important part of treatment.
Hamstrings & Gluteus Maximus –Strengthening the hamstring especially in eccentric control can have a positive effect in those with poor strength or control. The hip extensors in general can also improve gait mechanics which can have a trickle down effect on the knee stability
Hamstring – As the hamstring muscle group acts on both the hip & knee, a tight muscle will tend to draw and compress the joints affecting the joint space and further aggravating the knee.
Quadriceps – Although it’s often undervalued, the same applies for the quads as for the hamstrings. A tight quad muscle will pull the Tibia up and can reduce the joint space in the knee.
Calf Muscles – The muscles in the calf (mainly Gastrocnemius) also connect across the knee joint and if tight can decrease the joint space.
Ankle Range of Motion – The ability for the ankle to move freely during gait is important in controlling the mechanics of the lower limb. Improved mechanics and range of motion could serve to reduce the repetitive friction associated with knee osteoarthritis.
Muscular control involves improving the brain-muscle communication and subsequently activation. Untrained people often display poor muscular control during complex movements whereby muscles are not recruited in a normal pattern. Muscular control will improve during any type of structured exercise program (especially in untrained individuals) but specific exercises can be implemented that target muscular control.
There is plenty of research (Jordan, 2003) that identifies a positive effect of aerobic exercise on pain & disability in knee osteoarthritis. One possible factor is that aerobic exercise improves muscular endurance in the lower limb. Improved endurance means that the muscles can sustain load for a longer duration before they tire. Improvements in muscular endurance can lead to less wear on the joint over time. Muscular endurance can also be trained using resistance training in the form of holds and high repetitions.
Those individuals at risk for knee osteoarthritis should explore non-invasive treatment options as early as possible. Through targeted exercise prescription, knee osteoarthritis can be well managed and even prevented altogether. Sufferers should incorporate muscular strengthening, stretching, muscular endurance and control for optimal results.