starts: inital contact

ends: contralateral toe-off

starts: contralateral toe-off

ends: heel rise

starts: heel rise

ends: contralateral initial contact

starts: contralateral initial contact

ends: (ipsilateral) toe-off

starts: (ipsilateral) Toe-off

ends: feet adjacent with contralateral ankle

starts: feet adjacent with contralateral ankle

ends: tibia vertical

starts: tibia vertical

ends: initial contact

Double Stance 

(double support)

occurs during loading repsonse (0-10%)

and pre-swing (50-50%)

body's center of gravity is lowest here

Single Stance

(single support)

Follows Double Stance

makes up 40% of Gait Cycle

muscles are eccentrically active

0-10%

starts with intial contact

double stance

eccentric knee extension

decelerating fall due to gravity

ends with contralateral toe-off

10-30% 

COM decelerates approaching its highest base of support

once reaches highest base of support COM accerelates 

muslces eccentrically contract controlling acceleration

30-50%

COM is past Base Of Support 

accelerating due to gravity

ends with contralateral heel strike

50-60%

Double Stance

stance limb unloads

contralateral limb loads

PF accelerates limb into swing

ends with Toe-off

60-73%

first third of swing phase

foot clearance

acceleration to advance

ends with feet adjacent

73-87%

foot clearance 

limb advancement

ends with tibia vertical

87-100%

decrease swing rate

limb advancement complete

ends with knee fully extended

(before heel contact)

1. stability in stance

2. propulsion and progression

3. shock absorption

4. energy conservation

Center of Mass is in upper body

COM is anterior to lumbosacral joint forcing the trunk extensors to be constantly active to maintain upright position

Limbs are built for mobility not stability

gavity, musculature and passive ligaments maintain joint integrity

ligamentous skeleton built for forward mobility

rounded joints decrease tilt tolerance (no trapezoid)

1. free fall due to gravity

2. momentum conservation and transfer

3. stance limb mobility

4.forward swing of contralateral limb

Propulsion and Progression:

free fall due to gravity

body falling from high point (MSt) to a low point (PrSw)

is primary mechanism of progression

Energy needed to elevate COM

-muscles contract

-momentum from swing limb

Propulsion and Progression: 

momentum conservation and transfer

body falling from high point to low point is primary mechanism of progression

prior to high point: COM is behind GRF (&BOS)

after high point: COM in front of GRF (&BOS)

* NO GRF during swing phases

Propulsion and Progression:

Stance limb mobility

Heel Rocker

Ankle Rocker

Forefoot Rocker

Propulsion and Progression: 

Heel rocker

axis is calcaneus

to control forefoot drop, DF eccentrically contract

pulling tibia causing knee flexion (limited by simultaneou quad contraction)

Occurs during LOADING RESPONSE

Propulsion and Progression: 

Ankle Rocker

axis is Talocrural joint

forward movement pulls into DF (passively)

eccentirc soleus contraction to control tibial placement

occurs at MIDSTANCE

Propulsion and Progression: 

Forefoot Rocker

Axis is MTP Joint

forward progression is accerlated as COM moves away from BOS

"Falling"

assisted by strong Plantar Flexion

occurs at TERMINAL STANCE and PRESWING 

Propulsion and Progression: 

Forward swing of Posterior Limb

Contraction of Hip flexors and Plantar Felxors

*PF MORE IMPORTANT

provides forward momentum

COM momentum is low

end of Double Stance

uncontrolled free fall

abrupt weight transfer

talocrural joint: 

DF restrain progression of forefoot into PF

Subtalar joint:

initial supination allows greater pronation ROM

(*Eccentric DF contraction pulls tibia forward into knee flexion)

eccentric quad contraction to control knee flexion

Lateral tilt of pelvis & forward movement of COM cause the hip to abduct 

Hip abduction absorbs limb loading response

Minimal COM movement is Best

During gait COM moves: 

laterally-shifts weight

vertically-single support

Lateral pelvic tilt:

MIDSTANCE

COM is elevating

pelvic drop counters elevated COM (this is good)

Horizontal rotation:

occurs when swing leg advance infront of COM

pelvic rotation good to acheive optimal stride length

Change in these can double the energy needed to walk

Flexed:at initial contact

Extended:midstance-preswing

Flexed:preswing-terminal stance

Loading Response:

HIP

hip begins 30* flexed

stability maintained by 5 hip extensors

counters GRF

as trunk flexors decrease-> Hip ext. quieten

hip adduction restrained by abductors

Midstance:

HIP

hip extends

GRF center at hip joint-> GRF posterior to joint (extensors quiet)

single support (glute medius activated)

Terminal Stance:

Hip

GRF further posterior to hip joint

forward momentum pulls into passive hip extension

*Most amount of hip extension*

TFL fires to limit hip extension and low abduction force

Pre-Swing:

Hip

Beginning Hip Flexion &limb acceleration

HF assisted by

PF-> tibial progression-> KF & HF

rectus fem controls KF but assists HF

iliacus fires to increase cadence (swing)

Initial Swing:

Hip

Psw momentum continues HF thru ISw

passive limb advancement

if cadence increases:iliacus sartorius and gracilis fire

glute medius active thru all swing phases

Mid Swing:

HIP

continued hip flexion

passive momentum

hip flexors minimally active

Terminal Swing: 

HIP

ceased hip flexion: deceleration

controlled by hammys (also passive KE)

LATE TSWING HIP EXTENSION

glute max & adductor Magnus

Loading Response:

knee

early LP; KE for stability, GRF anterior to knee

Late LP; KF for shock absorption

GRF behind knee abrupt weight transfer