Gait

Question 1

gait speed

Answer 1

1. gait speed in m/s calculated using step length (m/step) and cadence (steps/minute), cadence usually 110-120 steps/min (cadence steps/min / 60 seconds = cadence steps/s), gait speed = step length (m/step) / cadence (steps/s)
2. comfortable walking speed adults 1.2-1.4 m/s, 4.5-5 km/hr

Question 2

temporal spatial parameters of gait
1. step length
2. stride length
3. toe out angle
4. walking base/step width

Answer 2

1. the ant-post distance between the heels of feet for one step, R step length is when R foot forward, L step length is when L foot forward
2. stride length is ant-post distance (at heels) covered by one foot in one GC, 1.45m at comfortable pace, sum of LR step lengths
3. angle between line of progression (movement) and foot line from centre heel to 2nd toe, 5-10 deg
4. med-lat distance between centre of heels, 10-15 cm, may be larger in obese individuals or those with pathology for better balance

Question 3

swing phase
1. early swing
2. mid swing
3. terminal swing

Answer 3

prepare to catch the fall, dual pendulum motion to advance swinging limb, req minimum foot clearance, each phase approx 10-15% GC
1. R TO forward acceleration of limb through hip flexion until peak anterior velocity reached with foot adj where R foot is in the same ant/post position as L foot
2. FA swing through slower acceleration through passive knee extension until R tibia is vertical
3. R TV decceleration of forward motion into R IC to prepare for loading phase where BW is transferred from R to L

Question 4

stance phase
1. loading
2. mid-stance
3. terminal stance
4. pre-swing

Answer 4

where at double, single support, or transfer of BW between
1. 10% GC, movement from double to single leg support, start with R initial contact with ground, loading R foot (absorbs E of impact) and transferring BW from L to R, until L opp toe off the ground
2. 40% GC, single support, L OTO, body COM travels over R foot until R heel rises off ground with L still in air
3. R HR, L foot in air falling phase as COM moves beyond forefoot BOS, catch with L OIC with ground
4. prepare for swing, transfer BW as L OIC loads left limb and deload R limb as R TO off ground

Question 5

gait

Answer 5

1. series of intentional falls progressing in a direction, COM is taken out of BOS, start to fall but catch self
2. comp swing phase (40% gait cycle) where leg is not in contact with ground, stance phase (60% GC) where leg has contact with ground, each leg has separate swing and stance phase

Question 6

stance phase kinematics
1. loading
2. midstance
3. terminal stance
4. pre-swing

Answer 6

1. land in a small squat motion to absorb impact with hip and knee flex, and passive ankle PF, COM shift up as shift BW onto target leg
2. brake with target leg as GRF in opp direction to force of COP, slowing target leg down as COM moves forward through hip and knee ext, begin to propel forward with foot still planted at balls, ankle DF
3. propel into fall through hip and knee ext, ankle DF, COM down with OIC
4. finish propelling through ankle PF while unloading target through hip and knee flex to lift foot into toe off

Question 7

swing phase kinematics
1. early/initial swing
2. mid-swing
3. terminal/late swing

Answer 7

1. accelerate the limb forward through hip flexion, knee flexion and ankle DF to get foot clearance
2. clear ground through hip flexion, knee flexion transitions to extension passively, and ankle DF
3. decelerate limb by slowing hip flexion and prepare for contact through knee extension while ankle stays in peak DF

Question 8

motion of COM through gait cycle
1. vertical displacement
2. horizontal displacement

Answer 8

1. COM oscillates up and down in sinusoidal motion through softening movement with ankle and knee, COM moves like pendulum with foot as anchor/swing point, highest single support, lowest double support
2. COM oscillate side to side, farthest from line of progression when single support

Question 9

peak values and timing of hip, knee, and ankle during stance phase

Answer 9

1. peak hip flexion 30 deg at initial contact, peak hip extension 10-15 deg at terminal stance
2. peak knee flexion 30 deg at pre swing for foot clearance, peak knee extension 0-5 deg at terminal stance propulsion
3. peak plantarflexion 10-15 deg at loading, peak dorsiflexion 10 deg at terminal stance

Question 10

pelvic and upper body rotation

Answer 10

pelvic rotates towards the opposite direction as the stance foot (forefoot) to give length to stride, upper body rot towards same side as forefoot (opp to pelvis) to keep head forward to maintain vision and balance

Question 11

foot kinematics through stance phase

Answer 11

1. pronation assoc with subtalar eversion, supination assoc with subtalar inversion
2. progressive weight bearing transition from initial contact with posterolateral heel (inversion/supination) to land stable with solid foot through deceleration, roll through eversion/pronation to soften foot to absorb impact to medial side hallux (while rearfoot switches to supination) where we push off to propel

Question 12

gait detours: foot drop
1. overview
2. compensation

Answer 12

1. foot in plantarflexed pos due to weak ankle dorsiflexors, possibly due to damage to peroneal/fibular nerve controlling PF (LMN)
2. to clear ground during swing, may pelvic hike or hip/knee flexion to clear ground, place foot flat on ground without heel strike roll or drag foot hanging in PF pos (steppage gait)

Question 13

gait detours: vaulting/hip hike

Answer 13

1. strategy to deal with functionally long leg due to stiff knee/hip due to arthritis or weak hamstrings/hip flexors (LMN)
2. during swing, opp limb PD to give vaulting (swing) side greater vertical height to clear the ground or hip hike swing side, can have partnered circumduction where swing leg externally rotates at hip so that adductors more anterior and can act as pseudo hip flexors for clearance

Question 14

gait detours: trendelenburg

Answer 14

1. weakness of hip abductors (glute med) due to neurological pathology of sup gluteal nerve, hip OA, or PFPS, (LMN)
2. causes lateral pelvic tilt to opp side during midstance, affected side is in adducted pos, laterally shift COM towards affected side during midstance for balance through trunk or pelvic motion where greater trochanter shifts towards weak side

Question 15

gait detours: hemiplegia and hemiparesis

Answer 15

1. paralysis or severe weakness with hypertonia (high muscle tone, hard to relax muscle) assoc with CNS pathologies and TBI (UMN)
2. upper extremity flexion in elbow, wrist, and fingers, forearm pronation, and shoulder adduct to keep arms close to body, functional long leg with knee extension and ankle PF

Question 16

gait detours: Parkinsonian gait

Answer 16

1. Parkinson’s disease, degen loss of dopamine producing cells in midbrain (basal ganglia, UMN), impacting motor control with tremors, shaking, stiffness, invol muscle contractions, difficulty balancing
2. manifest as limited upper and lower extremity motion and freezing (difficulty moving) when disruptions to current gait pattern occur such as navigating an obstacle in path, opening door, and change of direction, stooped shuffling; can be overcome by listening to other rhythms (e.g. metronome, music)

Question 17

ground reaction forces during stance

Answer 17

1. initial contact through midstance balance point, body applies forward down and forward, GRF acts as brake applying force up and posteriorly slow COM motion, muscle activation and starts high and decreases as float up to balance point, HGRF posterior and VGRF superiorly increase during loading and early midstance and decrease as float to balance point during midstance
2. midstance balance point no HGRF since not anterior or posterior motion, lower downward VGRF than FBW because unweight self from propulsion with other foot
3. falling phase body apply force down and posteriorly to propel, GRF aiding in forward motion, HGRF anterior and VGRF superiorly increase during mid and terminal stance and decrease as prepare to lift the limb through pre-swing

Question 18

goals for stance

Answer 18

1. prepare loading surface through PF after IC with heel to have a flat, bigger, and more stable surface to load
2. smoothly load BW through muscular control
3. propel COM over BOS with opp foot
4. stabilize pelvis and upper body, esp important to balance during single support (midstance and terminal stance) where there is small BOS

Question 19

goals for swing

Answer 19

1. accelerate swing limb forward
2. clear ground
3. decelerate double pendulum to prepare for landing
4. stiffen limb and set posiiton for IC, supination of foot for stable landing and prepare to land on posterolateral foot

Question 20

muscular activity patterns of gait: foot and ankle

Answer 20

1. ankle dorsiflexors: tibilais anterior ECC during passive PF through loading, CON through early swing for clearance, ISO maintain peak DF through mid and terminal swing
2. tibialis posterior: ECC to maintain MLA under BW as COM moves through midstance, transition to CON after heel rise to PF and supinate foot for propulsion
3. plantarflexors: soleus ECC to ISO through mid and terminal stance to control fall as COM swing over DF foot, contributes to knee extension during terminal stance by slowing tibia while femur rolls forward, transition to CON during pre-swing for propulsion

Question 21

muscular activity patterns of gait: knee

Answer 21

1. knee extensors: quadriceps ECC through small squat durign loading with greater activation of vasti compared to rec fem with less leverage in hip flexed position, active through midstance, co-activate with hamstrings through terminal swing just before IC
2. knee flexors: hamstrings ECC through terminal swing to decelerate passive knee extension and prepare for landing, weak hamstrings can cause uncontrolled flicking of knee into extension

Question 22

muscular activity patterns of gait: hip

Answer 22

1. hip flexors: iliopsoas ECC through terminal stance to control fall, transition to CON in pre-swing to clear ground, CON early and mid swing to accelerate limb forward, peaking during mid swing
2. hip extensors: glute max and hamstrings ISO (no hip drop) or ECC (hip drop into small squat) during loading, CON early midstance to float up to balance point, ECC terminal swing to decelerate hip flexion
3. hip abductors: glute med ISO to ECC through mid and terminal stance to prevent opp pelvic drop/lateral tilt during single support

Question 23

peak hip, knee, and ankle angles during swing

Answer 23

1. hip flexion 30 deg at terminal swing
2. knee flexion 60 deg at early swing, extension 0-5 at terminal swing
3. ankle dorsiflexion 0 deg at early swing

Question 24

upper motor neuron lesions
1. UMN pathway
2. changes in gait
3. pathology

Answer 24

1. cell bodies in motor cortex, axons travel through brainstem and descending tract of spinal cord, synapse (usually at interneuron) with LMN at ventral horn
2. lose ability to inhibit reflexes, can result in spasticity (velocity dependent muscle tone) when muscle rapidly stretches activates reciprocal inhibition (?), limiting motion, prolonged muscle contraction can lead to contracture (permanent shortening of muscle)
3. pathologies affecting the cortex, brainstem, and spinal cord, TBI, stroke, MS, SCI, tumors, and CP

Question 25

4 types of spasticity in gait

Answer 25

unilat or bilat 1. knee: extensors for stiff knee, potentially functionally long leg 2. ankle: equinus (PFs on balls of foot, change IC and propulsion in pre-swing) and equinovarus foot (inverters/supination), often through tib post, common in CP 3. hip: bilateral spasticity of adductors cause scissor gait where legs cross over midline, stiff narrow BOS makes it hard to maintain linear line of progression, often accompanied with hip flexed position (crouch), common in some types of CP 4. hip/knee flexors for crouch gait

Question 26

lower motor neuron lesions 1. changes to gait 2. pathology

Answer 26

1. paresis or paralysis, due to insufficient or lack of neural flow to muscle, atrophy, decrease muscle tome, reduced/absent reflex responses 2. at spinal and peripheral nerves, diabetic neuropathy, trauma-induced dmg to peripheral nerve, radiculopathy associated with disc herniation when hernia applies pressure on SPN, affecting all nerves it supplies

Question 27

pathologies with basal ganglia, cerebellum, and sensory input pathologies

Answer 27

1. basal ganglia and cerebellum pathologies have unsmooth gait, may struggle with coordination and timing of movements, consistent non-reflexive rigidity (high tone all the time, muscle fight each other), pathologies such as Parkinson's, stroke, tumor 2. visual, vestibular, and somatic disorders due to dmg to structures will impact sensory input received by brain

Question 28

ataxic gait

Answer 28

assoc with basal ganglia and cerebellum pathology, wide based staggering gait, irregular foot placement and trunk sway, often falling to one side

Question 29

antalgic gait

Answer 29

associated with pain, quick short step on one side to minimize time on painful leg

Question 30

other reasons for atypical gait

Answer 30

1. osteoarthritis: hip OA paired with weak abd results in trendelenburg 2. pregnancy: changes COM and increases mass, puts stress on the abductors to maintain balance, waddling gait (bilat trendelenburg) 3. obesity: increase BOS, challenging hip abductors 4. leg length discrepancy: vaulting/hip hike 5. prosthetic fit: consider how new limb changes gait