Yoga Anatomy: How Strong Thighs Can Help Knee Osteoarthritis
A series of articles from opinion leaders in the academic medical community have demonstrated the benefits of quadriceps strength for persons with arthritis of the knee joint. One of these studies, which used MRI to assess knee cartilage directly, is particularly important because it sheds new light on an earlier study (1)—that did not use MRI—that suggested stronger quadriceps were associated with a slightly greater risk of arthritis progression in persons with malaligned knees. Here’s a quote from the Mayo Clinic article, which was published in the December 2008 issue of Arthritis & Rheumatism (2) :
“In summary, in men and women with symptomatic knee OA [osteoarthritis], we found no association between quadriceps strength and cartilage loss at the tibiofemoral joint, including in malaligned knees. However, greater quadriceps strength, which may prevent lateral offset and tilt of the patella, protected against cartilage loss at the lateral compartment of the patellofemoral joint, a frequent site of symptom generation in knee OA. Subjects with greater quadriceps strength were also more likely to have less knee pain and better physical function. Our results suggest that strong quadriceps muscles have an overall beneficial effect on knee OA.” (2)
For Science Daily’s Composite of this article, and to see Mayo Clinic researcher Dr. Amin’s comments at The American College of Rheumatology Annual Meeting on Nov. 15, 2006. (3)
“A stronger quadriceps muscle helps keep the patella from moving laterally and tracking abnormally with movement … Our study results emphasize that it’s important to encourage people with knee osteoarthritis to maintain strong quadriceps muscles as recommended by their physician.”
These quotes are linked to the Science Daily summaries of the research. This is an excellent online publication you can use to stay current on scientific developments. They have a lot of integrity in their reporting and also provide full citations, as I do for Dr. Amin’s study. (2)
So the more recent study demonstrates that quad strength is not associated with increased cartilage wear—even in malaligned knees. In fact, it appears to protect against it for part of the patellofemoral joint (where the kneecap articulates with the femur). This is one reason I recommend using up-to-date articles from reliable sources like those referenced here to expand your knowledge base. Sound theory informs good practice and teaching.
The flip side is that unsound theory misinforms practice and teaching. For example, if you were to subscribe to the falsehood that people with strong quadriceps and misaligned kneecaps experience rapid progression of the disease—as some are now advocating for yoga—you might discourage your students from using these muscles in their poses. Then you would deny those same students, especially those with arthritis, the benefits of strengthening the quadriceps. You might also lose out on aligning the kneecap and reciprocal inhibition of the hamstrings.
Why Strengthen the Quadriceps?
I’ve written many times about the benefits of engaging the quadriceps. These include reciprocal inhibition of the hamstrings, which helps to release the muscles and protect against symptoms of overstretching. Contracting the quads also strengthens them, with the benefits outlined above. Finally, these muscles and their synergists align the bones of the leg and maintain congruency of the knee joint, thus protecting the cartilage. The tensor fascia lata (TFL) is one of the synergists that can be used to help stabilize the knee.
The tensor fascia lata can be used as a synergist of the quadriceps for knee extension. This muscle originates from the outer surface of the front of the iliac crest and the anterior superior iliac spine. It inserts onto the fascia lata (iliotibial band). This fibrous band of tissue runs down the lateral thigh and attaches at the upper outer surface of the tibia onto Gerdy’s tubercle (a small protrusion of bone). The TFL acts to flex, abduct, and internally rotate the hip. When you engage it, this also tenses the fascia lata, hence its name—tensor fascia lata. This tensing action is then transmitted to the insertion of the fascia lata on the tibia, aiding to stabilize and refine knee extension.
A New Yoga Cue to Protect Your Knees in Downward Facing Dog Pose
Using the quadriceps and TFL in Dog Pose.
1. Warm-up first with four or five rounds of Surya Namaskar (Sun Salutations) to acclimate the stretch receptors of the hamstrings and other muscles that lengthen in Adho Mukha Svanasana (Downward Facing Dog Pose).
2. Use the tips we have provided in the previous posts to lower the heels and spread the weight evenly across the soles of the feet.
3. Then, keeping your feet fixed on the mat, gently attempt to drag them apart (as shown above). This attempt at abducting the feet engages the TFL and brings added stability to the knee joint. Feel how this also brings kneecaps that are turning outward back to facing directly forward—the optimal position in the pose. This is because engaging the TFL acts to internally rotate the hip joint.
4. Lastly, feel how this cue also refines the hip flexion that is part of the form of Dog Pose.
Read about more yoga anatomy and practice tips from Ray Long, MD, and YogaUOnline – Yoga for Healthy Knees: Understanding Biomechanics Can Protect Your Knee in Lotus Pose.
This article is reprinted with permission from Daily Bandha.
Author Ray Long MD, FRCSC, is a board-certified orthopedic surgeon and the founder of Bandha Yoga. Ray graduated from The University of Michigan Medical School with post-graduate training at Cornell University, McGill University, The University of Montreal, and Florida Orthopedic Institute. He has studied hatha yoga for over twenty years, training extensively with B.K.S. Iyengar and other leading yoga masters.
3d Graphic Designer / Illustrator Chris Macivor has been involved in the field of digital content creation for well over ten years. He is a graduate of Etobicoke School of the Arts, Sheridan College and Seneca College. Chris considers himself to be equally artistic and technical in nature. As such, his work has spanned many genres, from film and television to video games and underwater imagery.
2. https://onlinelibrary.wiley.com/doi/full/10.1002/art.24182 Shreyasee Amin, Kristin Baker, Jingbo Niu, Margaret Clancy, Joyce Goggins, Ali Guermazi, Mikayel Grigoryan, David J. Hunter, David T. Felson Copyright © 2008 by the American College of Rheumatology
3. Wiley-Blackwell. (2009, January 20). Greater Quadriceps Strength May Benefit Those With Knee Osteoarthritis. ScienceDaily. Retrieved November 14, 2019, from www.sciencedaily.com/releases/2009/01/090113174539.htm