Can Yoga Reduce Symptoms Of Knee Osteoarthritis?

Yoga may reduce symptoms of knee osteoarthritis and improve knee function

Background

Osteoarthritis (the type of arthritis that occurs when the cartilage at the end of bones wears down) is a common condition which often affects the knee joints. Osteoarthritis is particularly common among those who are senior-aged and/or obese. Knee joint replacement is one way to deal with knee osteoarthritis. However, surgery is expensive and there is often a wait list to schedule a surgery for knee joint replacement. Additionally, many people are looking for other options to manage the symptoms of knee osteoarthritis. They may be looking for other options either before surgery, or instead of surgery.

Previous research already supports the use of strengthening exercises to reduce pain and improve the reduced functional movement which are the common symptoms of knee osteoarthritis. However, strengthening exercises vary in their ability to be helpful while simultaneously minimizing the risk of further pain or injury to the knee joints. Understanding the biomechanical loading on the knee joints from specific exercises, especially in the medial to lateral direction, can potentially help distinguish those exercises that could provide benefits while reducing risk of further pain or injury. Yoga postures offer one type of exercise that could potentially improve the symptoms of knee osteoarthritis without causing additional knee pain or injury.

Research question

Can yoga contribute to increased strength and improved knee function in women with knee osteoarthritis, without causing further pain or injury?

Research methods

A total of 39 participants took part in this study. This study focused on women who were 50 years old or older. Participants also met the criteria set out by the American College of Rheumatology for the condition of knee osteoarthritis. Potential participants were excluded from the study if they had other types of arthritis, other knee dysfunctions or conditions, had previously had knee surgery, or had experienced injury or trauma to a knee in the three months previous to beginning the study. All study participants were evaluated for the study parameters before and after completing a yoga sequence designed for the study.

The yoga treatment consisted of a 1-hour class which was held three times per week for 12 weeks. The postures included in the sequence focused on variations of weight-bearing squats and lunges, as well as transitions between standing, sitting, and lying down. Each class concluded with a section focused on stretching the muscles around the hips, knees, and ankles from a lying down, or supine, position.

Parameters evaluated in the study included:

• A biomechanical analysis of knee extensor and knee flexor strength measured by peak torque during isometric contractions
• Severity of symptoms of knee osteoarthritis were measured by completing the Knee Injury and Osteoarthritis Outcome Score. This included 42 questions marked by study participants on a scale from 0=extreme symptoms to 100=no symptoms
• Knee mobility was measured with three tests: a 6-minute walk test, a 30-second chair stand test, and a stair-climbing protocol
• Knee adduction moment (a type of biomechanical movement) was measured during gait before and after the yoga treatment, and during postures which were part of the yoga sequence
• Maximal oxygen consumption was measured on a cycle ergometer
• Electromyography (EMG) activity of five leg muscles (biceps femoris, semitendinosus, rectus femoris, vastus lateralis, and vastus medialis)

Results

The following measurements changed when evaluated before and after participants completed the yoga routine:

• Knee flexor strength increased
• Knee extensor strength increased
• 6-minute walk test scores increased
• 30-second chair stand test scores increased
• Knee adduction moment was lower during the yoga postures than when measured during gait (walking) before yoga

There was no change in the following:

• Knee adduction moment during gait before yoga versus after yoga
• Activity (measured with EMG) of five leg muscles when measured before and after yoga treatment
• Stair climbing protocol mobility scores before yoga versus after yoga

Why is this relevant to yoga practitioners?

Based on this research study, yoga has potential, as part of a larger treatment program, to offer some relief from the symptoms of knee osteoarthritis. This study also highlights the importance of knee placement. This is especially true for those experiencing knee osteoarthritis or other knee dysfunctions. This study suggests that weight-bearing yoga postures can contribute to increased knee flexor and extensor strength. They may also improve functional mobility. This study also reminds us of the importance of paying attention to where we place our knees with respect to the medial/lateral line of movement. That’s especially important when we are loading the knee joint with weight. Being attentive to these aspects makes it more likely that we experience the benefits of increased strength without causing injury or stress to our knee joints.

Reference citation

Brenneman, E.C., A.B. Kuntz, E.G. Wiebenga, M.R. Maly. 2015. A yoga strengthening program designed to minimize the knee adduction moment for women with knee osteoarthritis: A proof-of-principle cohort study. PLOS One. 10(9):19pgs.