Category: Applied Functional Science

Dischiavi SL, Wright AA, Hegedus EJ, Bleakly CM. Rethinking Dynamic Knee Valgus and Its Relation to Knee Injury: Normal Movement Requiring Control, Not Avoidance. J. Orthop Sports Phys Ther 2019; 49: 216-218.

This article in JOSPT (Journal of Orthopaedic & Sports Physical Therapy) is a “viewpoint” article. It cites research, but it is not a research article. It does not strictly fit into our Evidence that Matters for Function series. However, it signals an awakening in the physical therapy profession that long-held concepts about the knee specifically, and movement in general, are being questioned. For this reason, the principals at Gray Institute® felt that it merited serious analysis.

The three (3) key points that are listed at the conclusion of the article are:

  • “Dynamic knee valgus is a triplanar movement used to manage ground reaction forces and should be perceived as a normal motion requiring control rather than prevention.”
  • “Three-dimensional positioning of the body affects the global tension in the musculoskeletal system, ultimately affecting performance.”
  • “Appreciating how the trunk and pelvis rotate over a fixed femur (pelvis pronation) may inform new assessment strategies and therapeutic exercise design options for the lower extremity.”

At Gray Institute®, reading this article leaves us with an oxymoronic feeling. There is excitement that the statement above embraces four (4) of the primary principles of Applied Functional Science®: 3-D, Chain Reaction®, Load to Explode, and Driven. Yet there is also frustration that it has taken so long for movement practitioners to believe what they observe in function. In many situations, research should confirm what we observe and, therefore, do. We can’t wait for research to tell us what to do! The article states, “The complexity of the movement system can not be overstated.” The controls required for research and the limitations of measurement technology may never provide us the perfect answers to our clinical questions. Our patients and clients can’t afford to wait for proof. Research provides the “proof of truth” that we observe. The ultimate answer lies in the response of an individual human body to our specific interventions based upon the observation, experience, and any confirmatory evidence. And we can measure these responses.

The above statement may appear to be “heresy” based upon the demand for evidence for all that we do. So let’s look at the three (3) points made in the article. 

  1. “Knee valgus is “a normal motion requiring control.” It may be normal or abnormal depending on the movement and the driver of that movement. Because injuries can occur when knee valgus is not controlled, well-meaning “experts” have proposed that knee valgus should be avoided. Practitioners believed them even though their observations continued to tell then that 3-D motion is part of knee function. In fact, the knee valgus combined with internal rotation and flexion of the femur allow the strong posterior-lateral muscles of the hip to protect the knee.
  2. “Three-dimensional positioning of the body … ultimately affecting performance.” Regional interdependence has become a “buzz word” since it was described by Wainner et al in 2007. Unfortunately, this was 18 years after the beginning of the Chain Reaction® seminars from Gray Institute® (read more on this seminar and register for this event here: All parts work together as a system in a 3-D Chain reaction®: global interdependence.
  3. “Appreciating how the trunk and pelvis rotate over the femur…” At Gray Institute®, this has been part of the foundational teaching of Chain Reaction® Biomechanics for 40 years. Relative joint motion is produced by different combinations of real bone motions. There are five (5) different bone motion combinations that produce any joint motion. For a specific task or movement, one of these combinations is the most authentic to the system.

At Gray Institute®, we believe that we are the leaders in understanding functional movement. Sometimes we discover that we were wrong, and we are proud to admit that we were wrong because it means that our understanding is advancing. The Principles-Strategies-Techniques Process, that is the foundation of Applied Functional Science®, has allowed some clinicians to practice 20, 30, and even 40 years ahead of the “proof.” The overriding reason that we are ahead of the “understanding curve” is Dr. Gary Gray. One might ask, why has it taken so long? Something from the scriptures might serve as an apt analogy: “A prophet has no honor in his own land.” I consider Gary “a visionary that garners little respect in his own profession.”

“Pride cometh before the fall.” Are we tooting our own horn? Possibly. Are we promoting ourselves as better? Not intentionally. What we are really saying is that we can all serve our patients and clients better. From the tri-plane function of the foot in seminars started in the mid-1980s, to the articles proposing the role of the femur in patello-femoral problems in the late 1980s, to an article on the Achilles hip, to the Chain Reaction® seminars running for over 30 years, to the GIFT mentorship program for 13 years (read more on this life-changing and career-enhancing mentorship program:, the goal of Gray Institute® has always been to make you a better you so that you can serve your patients and clients better. 

The authors of this article state, “Physical therapists are challenged to appreciate human movement as a whole-system, 3-D construct.” We would add that all movement professions are so challenged. If you are reading this blog, we might be “preaching to the choir.” But why wait 20-30 years for the movement community to “awaken”??? Consider taking advantage of the content, certifications, and live events that Gray Institute® offers to understand, assess, rehabilitate, and train your patient and clients the way function instructs us. Your future can be NOW!

 1Wainner RS, Whitman JM, Cleland JA, Flynn TW. Regionalinterdependence: a musculoskeletal examination model whosetime has come. J Orthop Sports Phys Ther. 2007;37(11):658–60.


Evidence that Matters for Function: Ankle and Subtalar Joints – Vlog
Evidence that Matters for Function: Rethinking – The Truths of Human Function – Vlog

2 thoughts on “Evidence that Matters for Function: Rethinking – The Truths of Human Function”

  1. As a podiatrist, applied functional science has allowed me to understand all the ways the foot can impact the rest of the body, but more importantly when the rest of the body is impacting on the foot. I now use my skills to understand when the foot is the driver of the pain and when its just the victim.

    1. Many thanks for your valuable feedback, Tiarna! Applied Functional Science® certainly allows practitioners to become better at their craft, ultimately further impacting patients, clients, athletes, and individuals. We appreciate you sharing this and we very much look forward to having you with us for GIFT 2020!

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