Dr .Manal Radwan SalimLecturer of Physical Therapy

Pharos University

Pathomechanics of Gait and Dynamic Postures part 2

Determinants of Gait Cont: .

(2) Pelvic Tilt:5o dip of the swinging side (i.e. hip adduction)

maximum tilt is in mid swingAdvantage: Reduces the height of the apex of

the curve of COG by 3/8 inchPathologically: Pelvis dip increase downward

of swing side by weakness of abductors of stance limb. , or even pelvis raised up in swing in any problem leads to functional lengthening the swing limb.

Determinants of Gait Cont:.

(3) Knee flexion in stance phase: in Loading response, midstanceShortens the leg in the middle of stance phaseAdvantage: Reduces the height of the apex of

the curve of COG Pathologically: flexion degree may increases

(shorter stance than usual so gives apparent longer swing

Or there is limitation in flexion (longer stanced limb i.e affected give problems in other leg stance?!)

Determinants of Gait Cont:.

(4) Ankle Mechanism: lengthens the leg at heel contact Advantages: a)Smoothens the curve of

COGb)Reduces the lowering of COG

Determinants of Gait Cont: .

(5) Foot mechanism:While knee is flexed the leg is lengthened

at toe-off as ankle moves from dorsi flexion to plantar flexion

Advantages: a) Smoothens the curve of COG

b) Reduces the lowering of COG

Determinants of Gait Cont: .

(6) Lateral displacement of body:The COG is displaced laterally over the

weight bearing extremity twice during gait cycle( the motion produced by horizontal shift of pelvis and relative adduction of hip (max at mid stance).

Gluteus MaximusGluteus maximus shows peak

activity in IC, LR (i.e. weight acceptance), and TS, some activity in PS( weight

release).

Weakness in G. Max.: Appears in

Early stance: (@ IC, IC-LR).G. Max. contract to prevent jack-

knifing i.e. excessive hip flexion) and anterior pelvic tilt.

N. Path. GRFV

IC A to hip

LR

From this we can notice that:If bilateral weakness so The gluteus maximus lurch appears in both

early and late stance phases of rt limb and lt limb.

If unilateral (rt) so it appears in early stance of rt > in late stance of lt

Gluteus Maximus Cont.

Possible Compensation Patient leans trunk backward (so moves GRFV backward).

This is called gluteus maximus gait or Lurch gait

Hip FlexorsIn stance its activity starts at terminal

stance to preswing and increases to initiate swing .

Effect of weakness Toe may not clear the floor during swing “Toe Drag”.

Compensation: -circumduction at hip.

-Pelvic Hike

QuadricepsQuadriceps shows peak activity in LR

(i.e. weight acceptance). Some activity in TS and PS (weight release).

N. Path. GRFV

LRP. To knee

In Early stance: Quad. contracts to preventjack-knifing of knee. Possible Compensation: 1-Patient leans trunk forward (GRFV moves anterior). 2-Pt use arm as quadriceps by placing hand anterior to thigh, presses knee backward.3-Turn limb outward to lock knee passively.

Quadriceps Cont.

In Late stance:

Quad. contracts to control knee flexion

So in case of weakness the knee collapse into flexion leading to -premature flexion into early swing-‘rubber knee’

N. Path. GRFV

PSP to knee

In Early stance Cont.: 4- Contact ground with flat planter flexed foot so GRFV moves anterior. 5-place a shoe or cushion under heel which causes GRFV to move anteriorly.

Hamstrings In stance: It show little activity, support back of knee against extension moment of GRFV. In swing: *Assist knee flexion in IS. *Decelerates tibial shank in TSWeakness in Hamstrings:In Swing: 1- Inadequate knee flexion.

Late Swing: 2-Lack of control of swinging leg 3- Knee slapped into extension.

In Stance: 4-Reduction of restraining force of heel strike. 5-Progressive Genu Recarvatum.

Compensation:1- Increased hip flexion in swing2- Circumduction in swing hip3- Hiking with swing pelvis

Possible causes When in gait cycle

description Gait type

Spasticity in

Limited ROM, pain , …..

Weakness in

in early stance

Lean trunk backward

G. maximus lurch

or spasticity in quadriceps or planter flexors

Flexion of hip, knee or ankle

h. Flex, hamstring, dorsiflexors

swing Toe drag

Hip flexors, hamstring

swing circumduction

Hip flexors, hamstring

swing Pelvis hiking

Possible compensations

manifestation

When in Gait cycle

problem

Outward rotate leg to lock it passively

Place hand in early stance to push knee backward

Lean trunk forward in stance

Jack Knifing of knee

IC Quad weakness

place a shoe or cushion under heel so GRFV moves anteriorly.

IC with flat planter flexed foot so GRFV moves anterior.

Pelvis hiking

Circumduction Incresed hip flexion in swing

Progressive Genu Recarvatum

Mid stance

Hamstring

weakness

Reduction of restraining force

of heel strike

Knee slapped into extension

deceleration

Increased hip flexion

midswing

Pre-Tibial groupAnkle dorsi flexors shows peak

activity in IC, LR (i.e. weight acceptance).

Weakness in DF appears ina) Early stance: (@ IC, IC-LR).DF Contract to control forefoot

lowering. After forefoot contacts floor- pull tibia forward over foot.

N. Path. GRFV

IC P to ankle

LR

Pre-Tibial group Cont.

b) Swing phase:DF contract concentrically in swing sub phases 1- to lift toe up so prevent toes from dragging on ground. 2- functionally shorten swinging limb.

Compensation:In stance: no compensation what happen is forefoot

slaps to the floor ‘drop-foot’ gaitIn Swing: 1-Increased hip flexion

‘high steppage gait’2- Circumduction at hip.

Plantar Flexors (Calf muscle)

Calf activity in TS and PS, some activity in MS

Weakness in calfs appears in late stancemuscles show peak : as it controls dorsi flexion degree in MS and TS ecentrically.

N. Path. GRFV

A. To AnkleMS TS PS

Then contract concentrically to planter flex ankle joint in PS.Effect of Weakness:

Loss of forward thrust - poor transition to early swing

Plantar Flexors (calf muscle) Cont.

Possible Compensation:1- Outward rotate hips and pronate foot so

inner border contact the ground (flat foot gait or calcaneal gait)

2-Ankle maintained in planter flexion in mid stance to avoid excessive dorsi-flexion ?! (passively by genu recarvatum).

3-Maintain foot flat in TS to eliminate dorsi-flexion moment.

Hip Abductors Gluteus Medius

N. Path. of GRFV

LR MS TsMedial to to

hip

G. Medius contract in mid stance to prevent contra-lateral (swinging) hip from dipping greater than 5 – 80

Effect of weakness/absenceContra-lateral hip drops > 5-80 Compensation is to lean (‘lurch’) over stance-

side LE

COMMON GAIT ABNORMALITIES

A. Antalgic Gait.

B. Lateral Trunk bending.

C. Functional Leg-Length Discrepancy.

D. Increased Walking Base.

E. Inadequate Dorsi flexion Control.

F. Excessive Knee Extension.

COMMON GAIT ABNORMALITIES Cont.:

A. Antalgic Gait-Gait pattern in which stance

phase on affected side is shortened

-Corresponding increase in stance on unaffected side

-Common causes: OA, tendinitis

COMMON GAIT ABNORMALITIES cont.: B. Lateral Trunk bending’Trendelenberg gait

Usually unilateral, if Bilateral = waddling gait

Common causes:A. Painful hip B. Hip abductor weaknessC. Leg-length discrepancy D. Abnormal hip joint

COMMON GAIT ABNORMALITIES Cont.: C. Functional Leg-Length Discrepancy

Swing leg: longer than stance leg:Causes dicussed in details in muscle

weakness4 common compensations:

A. CircumductionB. Hip hikingC. SteppageD. Vaulting

COMMON GAIT ABNORMALITIES Cont.:

D. Increased Walking Base Normal walking base: 5-10 cm Common causes:

Deformities Abducted hip Valgus knee

Instability Cerebellar ataxia Proprioception deficits

COMMON GAIT ABNORMALITIES Cont.: E. Inadequate Dorsiflexion Control

In stance phase (Heel contact – Foot flat):Foot slap

In swing phase (mid-swing): Toe drag

Causes: Weak Tibialis Ant. Spastic plantarflexors

COMMON GAIT ABNORMALITIES: F. Excessive knee extension

Loss of normal knee flexion during stance phase

Knee may go into hyperextensionGenu recurvatum: hyperextension

deformity of kneeCommon causes:

Quadriceps weakness (mid-stance)Quadriceps spasticity (mid-stance)Knee flexor weakness (end-stance)

* * *

Gait in the Elderly Men - Murray, Kory & Clarkson

Gait was guarded and restrained - attempt to maximal stability and security

Gait in the Elderly Men - Murray, Kory & Clarkson

Gait resembled someone walking on a slippery surface decreased step &

stride legnth

wider dynamic BOS increased lateral

head movement decreased rotation

of pelvis

Gait in the Elderly Men - Murray, Kory & Clarkson

toe/floor clearance distance slightly decreased

lower stance-to-swing ratio

decreased reciprocal arm swing more from elbow than shoulder

Spasticity and its Impact on Gait

Spasticity - resistance to passive stretch

Spasticity & Gait

Effects: Restrict joint excursion Delay transition from one gait phase to the

next

Spasticity & Gait Examples

Quadcriceps May prevent knee from unlocking during

interim between HS and FF Knee maintained in extension leading to a

‘vaulting’ over stance limb or circumduction of hip

Disrupts (timing) transition to mid- and late stance

May prevent LE bending during swing phase

Spasticity & Gait Examples

Plantar flexors Increase in spastic tone may limit forward

rotation of tibia between MS and PO May locate ground reaction force well behind

knee causing significant flexion moment during late MS and knee buckling tendency

Ankle may be locked up during PO decreasing propulsive thrust forward - inefficient transition from TO to early swing

Spasticity & Gait Examples

Hamstrings May limit forward swing of LE - decreasing

step length May prevent knee from reaching a terminally

extended position just prior to HS

Pathway of GRFV during gait in sagital and frontal plane

StancePhases

SagitalHIP Joint Knee Joint Ankle Joint

SagitalFronta

lSagital Frontal Sagital Frontal

Heel Strike A

L

A L P N

Foot Flat A M P M P LMid Stance P M A M A LHeel Off P M A M A M

Toe Off P L P N A N