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ChiroCredit.com Presents: Biomechanics 202

Foot function and the Effects on the Core and Body Dynamics

Dr. Shawn AllenDr. Ivo Waerlop

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Today’s Goal = Gain Information

• to gain some more global knowledge about human gait• assist in injury risk and management• expand the interpretation of a patient’s global

presentation / disease / ailment

• * understand that what you “see” and what youclinically “find” are often 2 different things

• more knowledge will help you understand the“Why’s” behind what you see

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Gait Cycles

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Foot Tripod•we are dynamic machines moving over 2 

tripods, sort of

• loss of medial tripod is common• the foot and the homunculus• is the foot where the asymmetries begin ? 

R=L ?

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Impaired Forefoot Rocker

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•Using shoes to help rocker deficits

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Changing foot progression to help rockers

Is this helping or hurting ? 11

Gait is all encompassing

• gait control requires complete activation of the entire nervous system and musculoskeletal system

• gait requires both postural and phasic systems

• any movements, voluntary or involuntary require a postural framework from which the limbs move from/off of

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Janda’s Layered Syndrome 

• Tonic:  tight• Phasic: weak• any movements, 

voluntary or involuntary require a postural framework from which the limbs move from/off of

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Gait is all encompassing

• postural adjustments must anticipate the limb movements• faulty postural programs/patterns will predict faulty limb (gait) 

movements

• Volitional and non-volitional movements (as in arm-leg motions in gait) always accompany adequate and appropriate postural system control. The postural planning for dynamic stability of the human must fit volitional, anticipatory and reactionary plans and adjustments. This requires an intact cerebral cortex , basal ganglia, cerebellum, brainstem and descending systems. 14

Movement Rules

1. When the foot is on the ground, the gluteal muscles are in charge

2. When the foot is off the ground, the abdominals are in charge

Thus, would it suffice to say then that we need balanced, symmetrical, S.E.S. (skill, strength, endurance) in all 3 divisions of the glutes and all layers of the abdominals and their synergists to follow efficient locomotion ?

3. Asymmetry is the rule though !

Scand J Med Sci Sports. 2017 Jul 31. doi: 10.1111/sms.12953. [Epub ahead of print]

Kinematic stride cycle asymmetry is not associated with sprint performance and injury prevalence in athletic sprinters. Haugen T1, Danielsen J2, McGhie D2, Sandbakk Ø1,2, Ettema G2.

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Movement Rules

4. You must not cheat the CNS The power of compensation

Repetitive movement patterns made in compensation to an injury or improper training techniques get recorded in your central nervous system, both in the cerebellum (the motor coordination center) and the parabrachial nucleus (the pattern generator in the brainstem)

*Example: when the toes go down, the arch should not follow the pattern

J Physiol. 2015 Aug 1; 593(Pt 15): 3373–3387. Published online 2015 Jun 30. The neuromechanical adaptations to Achilles tendinosis .Yu-Jen Chang and Kornelia Kulig 16

Gait programs are variable

• principles of mobility and stability• locomotion is based off varying degrees and times of 

automated programs, and intentional programs depending on environment, distractions, intent etc.d

• distractions tap into executive function capacityJ Biomech. 2004 Jun;37(6):935-8.

Step width variability, but not step length variability or step time variability,

discriminates gait of healthy young and older adults during treadmill

locomotion. Owings TM1, Grabiner MD. 17

Gait Neurology

•motor programs utilize one’s body “schema” which is preserved and updated in the temporoparietal cortex

•motor programs are transmitted to the brainstem by the cortico‐reticuolospinal system so that posture is anticipatorily controlled

• this enable the corticospinal system to generate limb trajectory and achieve accurate foot placement

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Foot tripod restoration•when the toes go down, the arch should not follow 

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• Poll Question # 1

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Gait : automated control• rhythmic arm and leg 

movements

• the lower limb runs the show• Anti‐phasic gait shown here• pain and phasic often go 

together

• How might ankle rocker or hallux pain impact this ? Or affect arm swing?

• Why is internal hip rotation important? 

Ortop Traumatol Rehabil. 2015 Oct;17(5):455-62. doi: 10.5604/15093492.1186813.Correlation between Hip Rotation Range-of-Motion Impairment and Low Back Pain. A Literature Review.Sadeghisani M1, Manshadi FD1, Kalantari KK1, Rahimi A1, Namnik N2, Karimi MT3, Oskouei AE4.

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• Poll Question #2

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The effects of gluteus maximus and abductor hallucis strengthening exercises for four weeks on navicular drop and lower extremity muscle activity during gait with flatfoot

Young-Mi Goo, MS, PT,1 Tae-Ho Kim, PhD, PT,1,* and Jin-Yong Lim, MS, PT1 J Phys Ther Sci. 2016 Mar; 28(3): 911–915.

We like to say, "the load is going to go somewhere", the body will adapt. The problem is, we believe the body often looks for the easiest opportunity, not often the best one.

The body does not have the foresight to anticipate the consequences of its choices in the future. As long as the adaptation is not immediately painful, the choice often seems reasonable and thus is implemented.

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Trendeleburg gait

• Trendelenburg video case

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Foot Drop

•Foot drop video case• foot targeting changes• step width, length• postural control

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• Improper Forefoot loading video

• ‐ Shuffle walk skill• ‐ anterior 

compartment S.E.S.

• ‐ knee and hip flexion can occur if pattern is wrong

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• Right calf tight video

• Ankle rocker screen• ‐ foam roller under 

knees

• ‐ calf tight ?

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•Hip flexor gait

• ‐ Trampoline ankle Fx• ‐ knee hyperextension• ‐ ankle rocker impaired• ‐ hip flexion strategy

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• Ankle Circumduction video

• ‐ circumducting gait can originate from the hip or ankle

• ‐ peroneus brevis weak ?• ‐ lack of hip flexion ?• ‐ lack of ankle rocker ?• ‐ impact on the hips ?

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• Bouncy Gait video

• ‐ fixed or correctable ?

• ‐ it is a patterning problem that may be feeding off ablative or functional deficits

• ‐ cause ? cure ? Rx ?

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• Right Foot drop video case

• ‐ sometimes it doesn’t show up unless you tease it out

• ‐ some soft lesions can have a threshold

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Medial gait collapse

• 3 videos• A‐ Crossover uncorrected• A‐ Crossover Balance beam• A‐ Crossover Texas walk

• ‐ getting to the glutes and relearning joint stacking

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• B‐ External rotation/Frontal Plane video case

• ‐ failed ankle rocker• ‐ midfoot collapse• ‐ tib posterior insufficiency• ‐ weak right glute / frontal 

plane

• ‐ turning foot into frontal plane 33

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• C‐Peroneal Lesion Video Case

• ‐ head trauma• ‐ right foot drop• ‐ foot drop can be from weak 

peroneus brevis‐tertius

• ‐ weak left hip frontal plane• ‐ look for hip flexion and steppage

gaits and toe clearance issues

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• D‐ Loss Ankle Rocker video case

• ‐ congenitally blocked ankle rocker

• ‐ rearfoot pronation• ‐ medial knee collapse• ‐ cross over strategy• ‐ rigid apropulsive gait

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• do not coach out arm swing dislikes if you have not addressed the problems in the lower limbs

• photo: clearly left hip frontal plane sway, and right arm swing frontal plane sway.

• Those 2 limbs are neurologically paired. The arm is acting like a ballast in the opposite frontal plane to help her stay centered. She is failing, compensating, but at least not falling over.

• Focusing on the cause(s) of the left frontal pelvis-hip drift would be our direction, not coaching out the arm swing.

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•We hope you have a greater appreciation for the entirety of the system now in locomotion.

• The parts cannot be separated, and thus, for us to truly succeed, our examinations must be more comprehensive.

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Thank You!38

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