Dynamic knee valgus is frequently discussed in ACL rehab and return-to-sport training, particularly during cutting, landing, and deceleration tasks.
Because it has been associated with ACL injury risk, many rehab strategies attempt to eliminate knee valgus entirely, describing it as a “high risk position”. Athletes are often coached to keep their knees out, maintain perfect alignment, and avoid entering these positions during movement.
But when we examine how athletes actually move in sport, these positions are not only common — they are necessary for managing ground reaction forces during change-of-direction tasks.
The real question is therefore not how to eliminate dynamic knee valgus, but rather:
How do we prepare athletes to manage it?
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The Problem With Many ACL Rehab Programs
One of the major limitations in many ACL rehab programs is the lack of clear structure and progression.
Common strategies often include:
- avoiding knee valgus entirely
- coaching a constant “knees-out” position
- relying on anti-rotation strategies
- using highly internally focused cues
For example, athletes are frequently instructed to:
- “Stick the landing.”
- “Keep your knee out.”
- “Focus on your alignment.”
These instructions emphasize conscious joint positioning, which does not reflect the demands of real sporting environments.
In sport, athletes are not thinking about the exact position of their knee when they cut, decelerate, or land. Instead, they react to external demands such as:
- the ball
- an opponent
- the direction of movement
- the timing of the play
Another common limitation is the gap between basic strengthening exercises and high-level plyometrics.
Many ACL rehab programs move directly from traditional strength training to landing and jumping drills without first exposing athletes to rotational positions under load in slower, controlled environments.
This step is critical for developing the strength, control, and tissue tolerance required to manage the forces encountered during sport.
Dynamic Knee Valgus Is a Normal Movement Pattern
The framework proposed by Dischiavi et al. (2019) encourages clinicians to rethink how dynamic knee valgus is interpreted in ACL rehabilitation.
Rather than viewing it purely as a pathological position, the authors describe it as normal triplanar movement used to manage ground reaction forces.
This movement involves coordinated motion across multiple segments of the body, including:
- the trunk
- the pelvis
- the femur
- the knee
- the ankle and foot
This three-dimensional coordination allows the body to absorb and redistribute forces during athletic movements such as cutting, landing, and deceleration.
Because of this, dynamic knee valgus cannot realistically be eliminated during sport.
Instead, athletes must develop the capacity to manage these positions under increasing loads, speeds and unpredictability.
Applying the Framework to ACL Rehabilitation
Based on this perspective, ACL rehab programming should progressively prepare athletes across three levels:
- Mobility & Control
- Strength & Force Absorption
- Athletic Demands
1️⃣ Mobility & Control
Our job in rehab is to give athletes the resources they need to move safely and efficiently. Athletes must able to access and manage the positions required to absorb load during single-leg tasks.
Two key elements contribute to this:
Hip Internal Rotation
Adequate hip internal rotation allows the lower limb to participate effectively in load absorption and force distribution during change-of-direction tasks.
Research has shown that greater hip internal rotation is associated with improved performance and more favorable knee loading during sharper angle cuts.
It should be noted that hip rotation should not be assessed in isolation. Tibial rotation and ankle-foot mechanics such as pronation and supination should also be assessed as these factors contribute to rotational mechanics throughout the kinetic chain.
Pelvis–Femur Dissociation
Another key component is the ability to move the pelvis over the femur while maintaining control of the trunk and hip.
This relationship allows athletes to access the rotational mechanics required for absorbing forces during single-leg loading.
As highlighted by Dischiavi and colleagues:
“Socket-over-ball movement occurring in three planes is needed to facilitate the absorption of ground reaction forces and is a necessary component of human movement.”
2️⃣ Strength & Force Absorption
A second crucial element in ACL rehab programming is developing the specific strength to manage the triplanar movement of single-leg loads.
Two key elements should be emphasized here:
Loaded Rotational Strength
Exercises should be selected based on their capacity to reproduce the joint orientations and rotational mechanics of single-leg loading, but under greater external load.
These exercises typically involve the torso and pelvis moving over a fixed femur, helping athletes build tolerance to rotational forces in controlled environments.
Force Absorption Capacity
Strength exercises should progressively expose athletes to higher loads and faster contraction speeds, serving as a bridge between traditional strength training and the dynamic demands of return-to-sport training.
*MAKE SUR TO WATCH THE FULL VIDEO TO SEE EXAMPLES OF EXERCISES THAT CHECK THESE BOXES.
3️⃣ Athletic Demands
Finally, ACL rehab programming must prepare athletes to manage these rotational mechanics under the real demands of sport, which involves movement performed under speed, unpredictability and task constraints.
Understanding Instability in Sport
Instability is often misunderstood in rehabilitation.
Many programs attempt to create instability through unstable surfaces, such as BOSU balls or wobble boards.
Training on these surfaces primarily produces a response to surface tilt, where the athlete reacts to the angular displacement of the base of support.
This type of training can be useful early in rehabilitation, particularly after joint injury when proprioception and balance are disrupted.
However, this does not reflect how instability occurs in athletic environments.
In sport, the surface is typically stable and instability occurs when the center of mass is perturbed while the athlete remains on a stable surface.
Reactive Neuromuscular Control
To replicate these demands, training should introduce unanticipated perturbations that force athletes to rapidly regain balance.
Examples include:
- reacting to a moving object
- responding to directional cues
- absorbing unexpected forces
These drills better reflect the reactive nature of sport, where athletes must constantly adapt to external demands.
*MAKE SUR TO WATCH THE FULL VIDEO TO SEE WHAT THIS LOOKS LIKE IN PRACTICE.
A Shift in Perspective for ACL Rehab Programming
Dynamic knee valgus should not be treated solely as a position to eliminate.
Instead, ACL rehab programs should progressively prepare athletes to access, control, and tolerate these positions under increasing levels of load and unpredictability.
By structuring rehabilitation across three stages:
Mobility & Control
Strength & Force Absorption
Athletic Demands
rehab professionals can better prepare athletes to manage the complex forces encountered during cutting, landing, and return-to-sport movement.
Ultimately, the goal is not to eliminate movement variability, but to develop the capacity to manage it.
References
Dischiavi, S. L., Andriacchi, T. P., & Lewek, M. D. (2019). Rethinking dynamic knee valgus and its relation to knee injury: Normal movement requiring control, not avoidance. Journal of Orthopaedic & Sports Physical Therapy, 49(8), 590–599. https://doi.org/10.2519/jospt.2019.8788
Kohler, J. M., Flanagan, S. P., & Whiting, W. C. (2010). Muscle activation patterns while lifting stable and unstable loads on stable and unstable surfaces. Journal of Strength and Conditioning Research, 24(2), 313–321. https://doi.org/10.1519/JSC.0b013e3181c8655f
Havens, K. L., & Sigward, S. M. (2015). Cutting mechanics: Relation to performance and anterior cruciate ligament injury risk. Medicine & Science in Sports & Exercise, 47(4), 818–824. https://doi.org/10.1249/MSS.0000000000000471
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