Deprecated: Array and string offset access syntax with curly braces is deprecated in /home/customer/www/ on line 1093
Single Leg Movement and The Lateral Sub-System | Articles | Matt Johnson's Strength Coach Concepts

Single Leg Movement and The Lateral Sub-System

Have you ever thought of human movement as a puzzle?  Imagine puzzle pieces scattered across your coffee table.  Now, imagine a completed puzzle.  I tend to fall back on this teaching tool to help my athletes understand terms such as human movement, function and dysfunction.  Human movement consists of numerous sub-systems (puzzle pieces) to create performance (completed puzzle).  If one of the puzzle pieces (sub-systems) is misplaced then the puzzle is incomplete (dysfunction). 

      Muscle Dysfuction                    Muscle Function

      Muscle Dysfunction                               Muscle Function             

During movement our body simultaneously utilizes four sub-systems during activity.  The four systems are the Lateral Sub-System (LS), Deep Longitudinal Sub-System (DLS), Posterior Oblique Sub-System (POS) and the Anterior Oblique Sub-System (AOS).  It is important to remember that each system works together to produce integrated movement.

You may be asking yourself, “Why the Lateral Sub-System (LS)?”  What’s so important about the LS that merits it a topic for my discussion?  The answer is frontal plane and pelvo-femoral stability.  The LS is a component of the lumbo-pelvic hip complex, which along with the thoracic and cervical spine constructs the “core”.  On a side note, if someone tells you the core is composed of the abdominals, hand them a bit of literature.  Nevertheless, a strong/stable core will unleash performance enhancement that will astonish individuals who have developed strength and power in their prime movers.  At what cost will people step away from their nautilus training regimens and adopt a multi-plane, joint and vector methodology?  

The lateral sub-system is comprised of the Glute Medius, Tensor Fascia Latae (TFL), Adductor Complex (adductor magnus, adductor brevis, adductor longus, gracilis and pectineus) and the contralateral (opposite) Quadratus Lumborum.  In single leg movement, the LS complex controls the femur at both proximal and distal ends due to the origins and insertions of the glute medius and gracilis (adductor complex).

The LS is most involved in the “stance” phase of gait , primarily the single leg support micro-phase.  During single leg force reduction movement such as single leg landing/deceleration: pelvic and spinal stabilization relies heavily on the LS for support. Sports such as football, tennis and basketball need a strong synchronized Lateral Sub-System for efficient, risk free performance.  The exercises listed at the end of the following section target the LS as the primary stabilization system during each exercises ROM.

Single Leg Strength Movements and the Lateral Sub-System

In my opinion, the bilateral squat is the cornerstone movement for hip mobility, neuromuscular efficiency/coordination and patterning.  It is the first movement my athletes have to perfect before advancing any further in their training.  However, single leg movements are the “bread and butter” for lumbo-pelvic stability, postural support and improving injury prevention.  So I’m understood, I implement both methods in my training program.  It is note worthy that if you stress single leg movements on a regular basis the glute medius and tensor fascia latae will become plagued with trigger points, adhesions or in some cases ischemia (inadequate amount of blood to the area).  A perfect example of what occurs when “too much of a good thing” is implemented. 

Leg Separation Single Leg Patterns

  • Split Squat
  • Isometric Split Squat
  • Anterior Lunge (Forward knee drive, foot contact, push through heel, return to neutral)
  • Posterior Lunge (Backward foot drive, foot contact, push through contralateral heel, return to neutral)
  • Anterior or Posterior Barbell Walking Lunge
  • Lateral Lunge
  • Crossover Lunge
  • Bulgarian Split Squat (Trail leg elevated)
  • Rotational Squat

Single Leg Step Patterns

  • Barbell/Dumbbell Step Up (No Knee Drive)
  • Barbell/Dumbbell Step Up (Knee Drive)
  • Lateral Step Up (No Knee Drive)
  • Lateral Step Up (Knee Drive)
  • Alternating Step Ups (Front, Lateral, Crossover)
  • Crossover Step Up
  • Knee drive completes secondary step pattern, which is an advanced progression.  Stresses Lateral Sub-System (LS) more due to dynamic function and control of opposite leg.

Single Leg Squat Patterns

  • Single leg squat to 24” plyo box with overhead band assistance
  • Single leg squat to bench with overhead band assistance
  • Single leg squat to plyo step with partner assistance
  • Single leg squat to bench: Bodyweight, no assistance
  • Single Leg squat to plyo step: Bodyweight, no assistance
  • Single Leg Squat Full ROM: Pistol

Single Leg Deadlift Patterns

  • Single leg squat off plyo step.  Opposite foot dorsi flexed, proceed through ROM until heel contact.  Arms serve as counterbalance for balance
  • Single leg squat off 12” plyo box.  Opposite foot dorsi flexed, proceed through ROM until heel contact. Arms serve as counterbalance for balance
  • Single leg squat off 24” plyo box.  Opposite foot dorsi flexed, proceed through ROM until heel contact.  No arms.
  • Dumbbell Single leg deadlift (Knee flexed)
  • Dumbbell Single leg Romanian deadlift (Knee flexed)
  • Contralateral dumbbell single leg deadlift (Knee slightly flexed)
  • Contralateral dumbbell single leg Romanian deadlift

The above exercises are ways to successfully pattern each single leg movement variation.  Each movement targets the Lateral Sub-System and engages the lumbo-pelvic complex for stabilization.  

Lateral Sub-System: Assessment, Dysfunction and Correction

Assessment for the Lateral Sub-System is commonly performed in a dynamic environment such as during squats, lunges or gait analysis.  At first, I tend to lean toward a less dynamic environment and begin my assessment on the table with a few manual techniques for muscle strength, flexibility and function.   Why is the reason I do this?  The answer, what happens when and individual can only squat, lunge or patten in a limited ROM?  Did the feedback you received from the assessment produce reliable findings?  I think not. My defense?  Limited ROM during assessment = low reliability of diagnosis.  

As mentioned previously, the Lateral Sub-System involves the Glute Medius, Tensor Fascia Latae, Adductor complex and the Quadratus Lumborum.  Therefore, a manual examination would be performed on these muscle groups following the methods adopted from Muscle Testing: Techniques of Manual Examination 8th Ed. by Hislop and Montgomery.  After a manual examination is conducted, then dynamic protocols such as gait, trendelenburg, squat and split-squat are implemented.  

Assessment:  Manual and Dynamic Methods for Lateral Sub-System Evaluation

Glute Medius Manual Testing Procedures and Scoring:


Glute Medius: Gravity Resisted Scores: Grade 5, Grade 4, Grade 3

Patient is positioned on their side.  The pelvis is rotated slightly forward prior to administering the test.  The limb is extended and positioned slightly beyond the mid-line of the pelvis.  The patient abducts the hip throughout the available range. Resistance is applied at either the knee or ankle (practitioner’s discretion).  A grade of 3 does not involve any resistance.

  • Grade 5:Completes available range and holds against maximal resistance.
  • Grade 4: Completes available range and holds against moderate resistance.
  • Grade 3. Completes range and holds position without resistance. 

Glute Medius: Non-Gravity Resisted Scores: Grade (2) and Grade (1) 

The patient is positioned supine on the table.  Standing on the same side of the tested leg, the therapist supports and lifts the leg with one hand.  The leg is lifted just high enough to decrease friction on the table during the test.  The hand should not apply resistance or assistance to the leg during the test.  The opposite hand palpates the glute medius just above the greater trochanter.  

  • Grade 2: Completes range of motion supine with no resistance and minimal to zero friction.
  • Grade 1: Palpable contraction of glute medius but not movement of the leg.
  • Grade 0: No movement of the leg and no palpable contraction.

Tensor Fasciae Latae Manual Procedures and Scoring:

TRL: Gravity Resisted Scores: Grade (5), Grade (4), Grade (3)

The patient is positioned on his or her side.  The bottom leg is flexed to a 45-degree angle and the test leg is extended.  The therapist stands behind the patient around the area of the pelvis.  One hand is placed slightly above the knee while the opposite hand is placed at the crest of the ileum for stabilization and palpation.


  • Grade 5:  Completes available range (approx. 30 degrees) and holds against maximal resistance.
  • Grade 4: Completes available range (approx. 30 degrees) against moderate resistance.
  • Grade 3:  Completes available range (approx. 30 degrees) and holds without resistance.

TRL: Non-Gravity Resisted Scores: Grade (2), Grade (1), Grade (0)

Position:  The patient is in long-sitting, supporting their trunk by placing the hands behind the body.  Trunk may lean backward up to 45 degrees from vertical.

Procedure:  Standing at the side of the limb being tested.  One hand supports the limb under the ankle; this hand should either resist or assist during testing.  The opposite hand palpates the TFL on the proximal anterolateral thigh where it meets the IT band.  The patient abducts the hip through 30 degrees of range.

  • Grade 2:  Completes hip abduction motion to 30 degrees.
  • Grade 1:  Palpable contraction of TFL but no limb movement
  • Grade 0:  No limb movement or palpable activity

Adductor Complex Manual Testing and Scoring:

 Adductor Complex: Gravity Resisted Scores: Grade (5), Grade (4), Grade (3)

Position:  Patient is in side lying position with the test limb (lowermost) resting on the table.  The non-test limb (uppermost) is in 25 degrees of abduction, supported by the therapist. 

Procedure:  The hand giving resistance to the test leg (lowermost) is placed on the medial surface of the distal femur.  Resistance is directed straight down toward the table.

  • Grade 5:  Completes full range and holds against maximal resistance.
  • Grade 4:  Completes full movement and holds against moderate resistance.
  • Grade 3:  Complete full movement and holds end position against no resistance.

Adductor Complex:Non-Gravity Resisted Scores: Grade (2), Grade (1), Grade (0)

Position:  The patient is supine; the non-test limb is positioned in a slight degree of abduction to prevent interference with the test limb.

Procedure:  Standing on the side of the test limb, one hand supports the ankle and elevates it slightly off the table.  The opposite hand palpates the adductor mass on the inner proximal thigh. 


  • Grade 2:  Patient adducts limb through full range.
  • Grade 1:  Palpable adductor complex contraction but no movement.
  • Grade 0:  No palpable adductor contraction and no movement.

Quadratus Lumborum Manual Testing and Scoring:

Quadratus Lumborum: Resisted Scores:  Grade 5 and Grade 4

Position:  Patient is supine with the hip and lumbar spine in extension.  The patient grasps the edges of the table to provide stabilization during resistance.

Procedure:  Standing at the end of the table, the therapist grasps the test limb just above the ankle.  The therapist pulls slightly with a smooth/even pull.  The patient attempts to prevent against the pull of the therapist by hiking the pelvis toward the rib cage.  This test does not solely attribute to the quadratus lumborum.  However, it does serve as a point of reference for activation and strength.

  • Grade 5:  Patient tolerates maximum resistance.
  • Grade 4.  Patient tolerates moderate resistance.

Quadratus Lumborum: Non-Resistance Scores:  Grade 3, Grade 2

Position:  Patient is supine.  The hip is in extension and the lumbar spine is neutral or extended.

Procedure:  Therapist stands at the foot of the testing table.  One hand supports the leg just above the ankle; the other is placed under the knee so the limb is slightly elevated off the table.  The therapist does not apply any resistance or assistance during the test.   The patient attempts to bring the pelvis up toward their rib cage. 

  • Grade 3: Patient completes available range of motion
  • Grade 2:  Patient completes partial range of motion.

Grade 1 and Grade 0:  Grade 1 and Grade 0 scores should be avoided in the cause of clinical accuracy.  The muscle which pelvis elevation is attributed lies deep in the lumbar muscle mass and can rarely be palpated.

Dynamic Assessment Lateral Sub-System Protocols:

1. Trendelenburg Gait Test:  Glute Medius Assessment

   Read Article here. 

2. Body Weight Squat


3.Split Squat


Dysfunction of the Lateral Sub-System

      Dysfunction of the LS is apparent by increased pronation (flexion, internal rotation and adduction) of the knee, hip or feet during dynamic movement such as squats, lunges or walking/running.  Diagnosis can by simplified by the manual muscle testing methods listed above.  However, testing in a dynamic environment is also crucial.  The validity of manual testing is accurate to an extent.  In comparison, both methods are equally beneficial.  In fact, numerous protocols should be administered in order to be confident with your final diagnosis.  The photos below represent the anatomical pictures you may observe when performing testing in a dynamic environment.

Positive Trendelenburg:  Pelvic drooping; ipsilateral glute medius needs attention.

Knee Valgus:  Muscle imbalance/soft-tissue deficiency between adductor complex and glute medius. 

Overprontated foot during single support phase of gait.  If you look in the mirror you will notice pelvic drooping occurring.  Thus, the defense why glute medius work needs to be implemented.

Hallux Valgus:  Not necessarily a sign of dysfunction from a dynamic assessment standpoint but is certainly worth mentioning.  As depicted, Hallux Valgus is when the big toe deviates laterally toward the 5th metatarsal or the “baby toe”.  This condition can directly affect the Lateral Sub-System because it commonly appears on one side of the body (ipsilateral).  When this occurs, poor muscular integration occurs which results in a lumbo-pelvic impairment.  Hallux Valgus changes the way we transfer force throughout our feet.  When this occurs, the entire kinetic chain is directly affected.  The length-tension relationship of the lateral sub-system is compromised due to weak hip musculature caused by excessive medial rotation during walking, running and during life tasks.

Corrective Strategies for Lateral Sub-System Dysfunction:

I hope you enjoyed the pictures above and that they gave you an understanding for what to look for when assessing your athletes.  Did you notice anything about the pictures? You may need to use a bit of detective work to figure it out.  Okay, I’ll spill the beans.  The pictures are a continuum.  If you have a positive trendelenburg then valgus will be present.  If knee valgus is present then most likely over-pronation of the foot is present.  Finally, if overpronation is present there may be an outside chance Hallux Valgus is present.  So what am I ranting about?  LS dysfunction typically boils down to the glute medius.  I have had a few cases that this theory hasn’t been the case.   In these cases, LS dysfunction was due to an over tight adductor complex and a fair-moderate level of glute medius strength.  These cases would warrant soft tissue work, pin and stretch or external hip flexibility  (important underlying factor.  Simple, yes.  Pretty, no.) 

Instead of just telling you to do clamshells, monster walks or bridging.  I’ll take a few more swan dives into the deep end to finish covering this topic. 

Positive Trendelenburg: 

If the test is positive, I urge you not to jump right into strengthening exercise.  Instead inspect the glute medius for both active and latent trigger point sites.  Trigger points can influence muscle activation patterns, which result in poor muscle coordination and balance.  And you thought it was solely due to poor glute medius strength!

Here is my method for integrating trigger point therapy and glute medius activation. 

  1. Foam roll muscle area for 30 times. 
  2. Take a tennis ball and move in a clockwise and counterclockwise motion around trigger site #1- 20 times each direction
  3. Take tennis ball and place it at trigger point area # 1.  Apply a slight amount of pressure for 15 seconds.
  4. Repeat the same method for trigger sites 2 and 3 along with the spot pressure method.
  5. Single leg balance drills- Typically 4-5 exercises that consist of different movement patterns and velocity.  Why single leg balance drills to promote glute medius activation?  Play along for a moment.  Stand on your right leg.  Place your right hand on your hip.  Now spell your first and last name with your left leg.  I’m sure your leg was quivering with contractions from the TFL and Glute Medius.  There’s your answer.  It’s a rudimentary skill that elicits an adequate activation from the LS.

Perform the following sequence for roughly 2 weeks before progressing to strengthening movements.  Once completed, I recommend the progression below:

  1. Glute Medius Manual Test:  This isn’t only an assessment but can be used as an introductory strength exercise. 
  2. Clam Shells:  Body weight or mini band
  3. Bilateral Bridging
  4. Monster Walks with Mini Band- Forward and Backward
  5. Lateral Band Walks
  6. Single Leg Bridging
  7. Single Leg “Potty” squats

Knee Valgus:

The glute medius strategies listed above can be very useful.  However other methods can be used to correct this deficiency. 

  1. Soft Tissue or Trigger point therapy.
  2. External Hip flexibility
  3. Body went squats with plate under the 1st metatarsal.  2.5 kg “cookie” plate works wonders.  With or without overhead band assistance.
  4. Body weight squats with medial and lateral band resistance or assistance.  I use my gray cook bands for this all the time.
  5. In-line Lunges
  6. Single Leg “Potty Squats” with  “cookie” plated under 1st metatarsal.  With or without overhead band assistance.

Over-pronation of Foot:

Over-pronation of the foot can typically be corrected by using the glute medius and knee valgus methods listed above.  A few more exercises I highly recommend are:

  1. Trigger point therapy of the anterior tibialis.  Controls dorsi-flexion of the foot.  Active and latent sites will prevent proper metatarsal control.
  2. Peg Legs- Walk or stand on heels for reps or time.  This will elicit an isometric response from the AT.
  3. Seated Toe Raise- You can perform this with a plate of mini band.  Typically performed with for repetitions.
  4. Plantar fascia rolls with tennis ball.
  5. Gastroc-Soleus Stretch- Stand 1 foot away from wall.  Try to lean forward and touch knee to the surface of the wall.  This is not like the traditional wall stretch.  In fact, it’s quite the opposite.  Instead of feeling the stretch in the trail leg you will feel a stretch in the lead leg.

Closing Thoughts

I understand this information may seem a bit overboard.  It is important to remember that sport specific movement occurs in many planes.  Therefore, to move efficiently each sub-system must operate at full capacity.  The slightest deficiency will lead to incorrect movement mechanics, articular/tissue stress and injury.  Assessment, diagnosis and correction of the Lateral Sub-System is just the beginning.  The same amount of time and effort should be extended toward each unit.  In my program the LS has always been the first system I investigate.  If you talk to someone else they may suggest a different system.  However, it’s hard to deny that the LS is a critical component to efficient jumping, landing and sprinting mechanics.  Placing a focus on it early will help build a significant amount of “starting strength” which in turn will build amazing muscle strength and integration in the future.  You could spend all the time in the world teaching landing or sprinting mechanics but if the athlete at hand has a system dysfunction unfortunately your time in a sense is wasted.

What are your thoughts?  As always, your feedback is greatly appreciated.  Leave a comment below or email me your thoughts at

Yours in Performance,




© All Rights Reserved. Reproduction without permission prohibited. Web Design by Ennui Design