Kinesiology Gait Cycle

What is Gait Cycle? How many percentage can person represent the gait cycle?

Gait cycle = the most fundamental unit of walking

represented as 0-100%

How can you tell phase and support of gait cycle?

Phases - a single limb is the reference

Support - considers both limbs

What does stance phase mean?

Stance phase means that foot (in contact) on the ground; 60%

What does swing phase mean?

Swing phase means that foot NOT in contact with ground; 40%

What does double-limb mean?

both feet in contact with ground; 20%

What does single-limb mean?

only one foot in contact with ground (80%)

As gait speed increases, % time in double limb support [increase or decrease]

decreases

As gait speed decreases, % time in double limb support [increase or decrease]

increases

Tell me comparison of terminology of gait cycle (8 RLA cycle)

1. initial contact (IC)

2. roading response

3. midstance

4. terminal stance

5. preswing

6. initial swing

7. midswing

8. terminal swing

What does event of stance phase mean? (4)

• heel strike/ heel contact

• foot flat

• heel off

• toe off

What does event of swing phase mean? (3)

• early swing/ acceleration

• midswing

• late swing/ deceleration

When the person’s heel touches on the ground, what phase and percentage of this gait cycle?

initial contact - point at which the heel strikes ground (0% gait cycle)

When the person’s foot flat on the ground, what phase of this gait cycle?

roading response - first point in stance time that foot is flat on ground

When the person stands following of foot flat, what phase and percentage of this gait cycle?

midstance - point at which BW is over support limb (double-limb); 30%

When the person’s heel off on the ground, what phase and percentage of this cycle?

terminal stance - point at which heel leaves ground (~40%)

When the person’s toe off on the ground, what phase and percentage of this gait cycle?

preswing - point at which toe leaves ground (~60%)

Describe the early swing (initial swing) phase including with the percentage of the gait cycle

Acceleration phase: toe off → midwing (~60-75%)

Describe the midswing phase including with the percentage of the gait cycle

When LE passes under body (~75-85%)

Describe the late swing (terminal swing) phase including with the percentage of the gait cycle

Deceleration phase: After midswing, limb decelerating for Heel contact (~85-100%)

For loading response phase (LR), can you describe what is happening in this phase? describe weight transfer and other key things.

• describe weight transfer to stance limb (lC→LR is double-limb support)

• foot flat position

• shock absorption occurs as forward momentum (moving to forward and flexing hip, knee, ankle)

What are the critical events of weight acceptance between IC to LR phase?

• heel first contact (Dorsiflexion → Plantarflexion)

• hip stability; controlled knee flex and plantarflexion

What are the critical events of mid stance → terminal stance?

Single limb support = midstance + terminal stance

• controlled tibial advancement (=midstance)

• controlled ankle dorsiflexion with heel rise; trailing limb (=terminal stance)

Explain RLA of swing phase including with motion (3 phases)

1. initial swing (Acc): end of double limb support (toe off)→ max knee flex; 62-70%

2. mid swing: max knee flex → tibia vertical; 70-80%

3. terminal swing: tibia vertical → just prior to IC; 80-100%

What are the critical events of swing phase?

1. preswing: passive knee flexion; ankle PF

2. initial swing: hip flexion; knee flexion

3. midswing: more hip flexion and ankle DF

4. terminal swing: knee extension

What is the step length?

distance between heel contact of opposite LEs; 72 cm

What is the stride length?

distance from one heel strike to the next on the same LE; 144cm

this affected by leg length, height, age, sex, etc.

What is the step width?

distance between midpoints of L and R heels (base of support); 8-10cm

Images of healthy step length and step length of painful hip

healthy step length - seems symmetry

painful hip - decreases step length which also can cause decreasing the next step length, too

Images of step length between healthy and hemiparesis

decrease step length

extend hip on the paretic limb because of weakness on this side of limb

Images of step length between healthy and Parkinson’s disease

• decrease step length and tiny step forward length

Review: Name the percentage of gait cycle!

1. Stance time

2. Swing time

3. Single-limb support time

4. Double-limb support time

1. 60%

2. 40%

3. 80%

4. 20%

Double-limb support time decreases in older adults and people with balance disorders

Double-limb support time decreases with increasing gait speed and running.

Stride and Step Duration

Step duration = second/ step

• ~0.5 sec

• decrease with painful stance LE

Stride duration = gait cycle duration

• ~<1 sec

What is cadence? What is the norm of walking speed?

Cadence = # of steps per time

• 1.87 steps/sec or 110/min

• decrease step length = increase cadence

Walking speed

• rate of forward progression, without considering direction

• 1.2-1.5 m/s or ~3mph

• 1.2 m/s = cross the street safely

• 0.47-0.68 m/s: normal gait speed one year post hip fracture

In sagittal plane, what is the maximum flexion and extension of hip? what does it occur to the pelvic tilt?

• max flexion = 20 degree - just prior to IC

• max extension =10-20 degree - heel off (terminal stance)

• Pelvic tilt: less than 5 degrees each direction

  • Anterior: hip moves into apparent extension (looks like hip extending)

  • Posterior: hip moves into apparent flexion (looks like hip flexing)

What are compensations of limited hip extension ROM?

anterior pelvic tilt at heel off

lumbar lordosis increases (extends)

What are compensations of limited hip flexion ROM?

• anterior pelvic tilt at heel off

• decreasing lumbar lordosis

What is the maximum degree of knee flexion and extension? What phase does occur in the maximum degree of knee flexion and extension?

The max extension = 0 degree

• IC, heel-off, late swing (terminal swing)

The max flexion = 60 degrees

• midwing

What are compensations of limited knee flexion ROM?

• increase ipsilateral hip flexion

• hip hike (trunk side bend and rotation)

• circumduction gait (回旋運動); vaulting

What are compensations of limited knee extension ROM?

• contralateral hip and knee flexion

• increase quads demand since knee is flexed

What is the maximum degree of ankle dorsiflexion and plantarflexion?What phase does occur in the maximum degrees of each motion?

Ankle dorsiflexion = 5-10 degree; occurs after midstance

Ankle plantarflexion = 20 degree: toe-off (preswing)

What is the maximum degree of great toe dorsiflexion and plantarflexion?What phase does occur in the maximum degrees of each motion?

1st MTP: 45-60 degree hyperextension; occurs between heel-off and toe-off

0 degree (neutral) during swing phase

Greater ankle dorsiflexion is needed during the [stance or swing] phase of gait.

stance

The best view of sagittal plane kinematics would be from the ____.

side

The best view of frontal plane kinematics would be from the _______.

front or behind

In the frontal plane, how many degree does pelvis-on-femur (hip) AB or ADduction?

~5 degree

In the frontal plane, what happens if pelvis drops on swing limb in early stance?

stance hip AD (imaging the closed-chain of hip)

In the frontal plane, what happens during late stance and swing phases on the hip and pelvis?

stance (standing leg) hip progressively AB

pelvis elevates on swing limb

What happens if pelvis-on-hip movement would excessive?

Trendelenburg Gait

Patient diagnosed L5 nerve root compression with subsequent discectomy and laminectomy. When patient performed Trendelenburg gait (weak on the L side of hip), which side should patient bring a cane? Which muscles affected?

Patient should place a cane on R side.

Her left side of hip AD muscles, AB muscles, and glute med would weak. It would cause hip drop on the R side.

When the patient has compensated Trendelenburg gait, what would cause?

minimize the external torque demands resulting from body weight on the AB muscles.

my words: lean the back and pelvis towards the weak side and keep the pelvis elevating on the strong side.

1. At IC, calcaneus is [everted or inverted] 2-3 degrees.

2. Then, rapid [eversion or inversion] 2 degrees → shock absorption & adaptation

3. 6 degrees [eversion or inversion] reached between terminal stance (heel-off) and pre-swing (toe-off) → Rigid lever for propulsion (one side of ankle rigid inversion)

1. inverted

2. eversion

3. inversion

Review: What does kinetics mean?

describe the effect of forces on a segment

ultimately responsible for the kinematics

What does external force produce? How does it measure?

external force produces external torque/moment

it’s measured with scales, force platforms.

ex) Ground Reaction Force (GRF)

What does internal force produce? How does it measure?

Internal force produces internal torque/moment to resist external torque/moment

1. muscle

   1. responds to GRF

   2. Controls or generates movement

   3. estimated with dynamometers, mathematical calculations, EMG

2. ligaments, capsule, other ST and bony structures

What is the ground reaction force (GRF)?

• force of the ground pushing back on the foot.

• equal and opposite to the line of gravity (LOG) in static standing posture

• produce external moment/torque

What is the center of pressure (COP)?

• location of the GRF vector

• based on weighted average of all downward acting forces (foot placement, gravity, ankle muscles)

1. When the line of gravity (LOG) passes directly through a joint axis, _________ is created around that joint.

2. If the LOG passes at a distance from the axis an __________ is created.

3. The external moment will cause rotation of the superimposed body (重なりあわせた) segments around that joint axis unless it is opposed by a counterbalancing _________ (muscle contraction).

no external gravitational torque

external moment

internal moment

External and Internal Moments Rules

Fill in the blank of sentences or choose the word.

4. The magnitude of the gravitational moment of force [increases or decreases] as the distance between the LOG and joint axis increases.

5. If the LOG is ANTERIOR to a joint axis, the external gravitational moment will cause __________ of the proximal segment (flexion or extension)

6. If the LOG is POSTERIOR to the joint axis, the moment will cause _______ of the proximal segment (flexion or extension).

4. increases

5. anterior motion

6. posterior motion

Quiz!

1. When you try to heel off on the ground, what external moments on the ankle and 1st MTP happen? what about internal moments?

2. When you try to toe off on the ground, what external moments on the ankle and 1st MTP happen? what about internal moments?

1. As the external moments, more dorsiflexion moment at the ankle and extension on the 1st MTP. Internal moments on the ankle would be plantarflexion, and 1st MTP’s internal moment would be flexion

2. external moment on the ankle would be dorsiflexion and extension on the great toe. Internal moment on the ankle would be plantarflexion and flexion on the great toe.

If kinematics and external moment occurs in the same direction

eccentric contraction to control movement

If kinematics and external moment occurs in the opposite direction,

concentric contraction to generate movement

What about constant position of the kinemactics and external moment?

isometric contraction to stabilize segment

What muscles stabilize the thigh?

What muscles extend the knee?

What muscles act motions on ankle?

Glute max and adductor magnus stabilizes thigh

Hamstring counteract extension torque (quads may contact in prep for LR)

Tibialis Anterior & Long Toe Extensors (pretibial muscles)

What muscles ?

What muscles flex the knee?

What muscles act motions on ankle?

Extending and flexor external moment to concentric glute max, adductor magnus, and hamstrings

Flexing and flexsor external moment so eccentric quads

Plantarflexing and plantarflexors of the external moment so eccentric dorsiflexion (tibialis anterior)

What causes Backward Trunk Lean of Gait Deviation?

Cause:

• WA (weight acceptance) or SLS (single-limb support): Intentional to decrease the demand on the hip extensors (puts the LOG posterior to the hip joint axis)

• Single limb advancement (SLA): intentional to advance the limb

What significant Backward Trunk Lean of Gait Deviation?

• WA (weight acceptance) or SLS (single-limb support): may increase energy cost, decreases forward momentum

• SLA: may increase energy cost

What functional activity would increase activity of the hip extensors?

walking on the hill

What problems on the ankle would happen in single limb support?

• excess DF/PF

• excess inversion/eversion

• heel off

• no heel off

• toes inadequate extension

• toes clawed/ hammered

What problems on the knee would happen in single limb support?

• excess flexion

• wobbles

• hyperextends or extension thrust

• varus/valgus

What problems on the hip would happen in single limb support?

• inadequate extension

• internal/external rotation

• adduction/abduction

What problems on the pelvis would happen in single limb support?

• posterior/ anterior tilt

• lacks backward rotation

• excess forward/ backward rotation

• contralateral pelvic drop