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4 Credits

Lower Extremity Dysfunction (LED): Predictive Model of Lower Extremity Movement Impairment

Predictive Model of Lower Extremity Dysfunction (LED): Signs of lower extremity/lower body postural dysfunction, muscle, joint, fascia, nervous system, neuromuscular recruitment, subsystems, and core muscle contribution. Exercise selection related to pronation distortion syndrome, feet flatten, forward lean, and feet turn out.

Brent Brookbush

Brent Brookbush


Course Description: Lower Extremity Dysfunction (LED)

“Lower Extremity Dysfunction (LED)" is an edit and update of previous postural dysfunction models (e.g. lower body posture, lower-crossed syndrome, pronation distortion, functional knee valgus, etc.). It is important to recognize that in these models the term "posture" is being used as an analogy for "ideal alignment". Similarly, when movement professionals refer to lower body posture, good posture, poor posture, better posture, etc. they are referring to this analogy of ideal alignment; not the rigid positioning implied by the colloquial use of the term "posture."

Postural dysfunction and movement impairment syndromes are likely the beginning of "modeling". Modeling has significant potential to aid in refining clinical decision-making, intervention selection, program design, and improve the reliability and effect size of outcomes. Models are especially conducive for assisting in interpreting multi-variant problems, which is how all clients and patients present. The Brookbush Institute recommends that all sports medicine professionals (personal trainers, fitness instructors, physical therapists, massage therapists, chiropractors, occupational therapists, athletic trainers, etc.) consider these models as an aid in refining decision-making in practice.

Additional Models:


  • Posture: Arthro- and osteo-kinematics alignment maintained by optimal myofascial activity and length, as a result of sensation, integration, and activation by the nervous system - both statically and dynamically.
  • Postural Dysfunction: The absence of ideal posture as a result of maladaptation by one or multiple tissues within the human movement system.
    • Brookbush Institute Modern Definition: Modeling patterns of movement impairment correlated with orthopedic dysfunction, based on all available evidence, with the intent of predicting best-practice assessments and techniques, to optimize measured outcomes.


Fascia (Reduction in Extensibility)

Restricted Mobility (Thickening, histochemical changes, decrease in tensile strength, addition of disordered collagen fibers)
  • Sacrotuberous ligament
  • Iliotibial Band
  • Crural Fascia
  • Achilles Tendon
  • Plantar Fascia
Recommended Techniques

Additional manual techniques:

  • Instrument Assisted Soft Tissue Mobilization
  • Pin and Stretch

Myofascial Synergies (Altered Recruitment)

Under-active (Integrate)

Over-active (Release and Avoid)





Mobility Restriction (Stiffness)
  • Ankle: Inadequate posterior glide of the talus on the tibia
  • Ankle: Inadequate posterior glide of the lateral malleolus on the tibia
  • Ankle/Knee: Inadequate anterior glide of the fibular head on the tibia
  • Knee: Inadequate anterior glide of the tibia on the femur (the lateral compartment may be more restricted)
  • Hip: Inadequate posterior/inferior glide of the femur in the acetabulum
Recommended Assessments:
  • Passive Accessory Motion Assessment

Recommended Techniques:

Signs of Dysfunction

Overhead Squat Assessment :

Goniometric Assessment

Muscle Length Tests

Manual Muscle Tests

Correlated Injuries, Pathologies, and Pain

The Lower Extremity Dysfunction (LED) model is constructed based on research demonstrating the maladaptive alterations of tissues and motion associated with common impairments of the human movement system. Creating a list of these impairments adds to the definition of the LED model, as the model itself could be defined as the expected maladaptive changes to arise from those impairments.

  • Ankle/Foot
    • Medial tibial stress syndrome (24, 34, 44)
    • Pronation (30, 34, 44)
    • Ankle Sprain (Inversion sprain) (62, 75, 123-124, 195, 198 -199, 203 - 204, 207, 211-212)
    • Ankle instability (19, 34, 71 - 74, 126, 196-197, 200 -202, 205-206, 208-210, 213, 218)
    • Achilles tendinopathy (31, 34, 42, 44, 156, 159-167)
    • Tibialis posterior tendinopathy (36 - 39, 110, 115-117, 121
    • Plantar fasciitis (plantar heel pain,) (43, 69, 111, 153-158)
  • Knee
    • Anterior cruciate ligament injury (16, 230, 234)
    • Functional valgus (16 - 18, 23, 26-29, 234)
    • Knee pain (patellofemoral pain syndrome, jumper's knee ) (46, 48 - 51, 53-54,56, 58-59, 93, 102, 170, 225, 234-236)
    • Lateral knee pain (iliotibial band syndrome, runner's knee) (172, 215-216)
    • Knee osteoarthritis (217, 224, 227, 228)
    • Knee effusion (100)
    • Proximal tibiofibular joint pathology (215-217)
    • Tibiofibular joint subluxation/dislocation (218-222)
    • Medial and lateral heel whip (45)
  • Hip
    • Trigger points (84)
    • Abductor tendon tear (87)
    • Adductor Groin Strain (94 - 97)
    • Femoral acetabular impingement (FAI) (238)
    • Hip Osteoarthritis (83, 239)
  • Lumbosacral
    • Low Back Pain (76, 78, 128-129)
    • Sacroiliac joint pain (77)


Summary of Model

5 sub-categories

Considering the Traditional Model of Lower Extremity Dysfunction

Signs of Lower Extremity Dysfunction

Osteokinematic Dysfunction

1 sub-category

Evidence-Based Muscular Approach

4 sub-categories

Introduction of Fascia into a Predictive Model of Movement Impairment

5 sub-categories

Myofascial Synergy a.k.a. Subsystems

4 sub-categories

Arthrokinematic Dysfunction


3 sub-categories

Symptoms, Injuries and Diagnoses Associated with Lower Extremity Dysfunction LED

Thank You


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1. Introduction

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