Normal Gait Biomechanics and Gait Analysis Flashcards
what are the 3 requirements for successful human locomotion and what is the order in which they emerge
progression
postural control
adaptability
ability to generate a rhythmic stepping pattern to move the body forward, is present in limited form at birth and refined during 1st year of life
progression
ensures orientation and stability, emerges toward the end of the first year of life
postural control
ability to adapt gait to changing task and environmental requirements; refined in the first years of life after onset of locomotion
adaptability
when do rhythmic pattern generation of gait being
prenatally
(isolated head and arm movements at 9 months in embryo, alternating leg movements similar to walking develop in embryo by 16 weeks)
reciprocal kicking/turns head
1 month
may roll supine to prone, midline head
2-3 months
pivot prove, rocking in quadruped and push backwards, bears weight in standing
4-5 months
moves forward with arms with or without abdomen elevated, rolls, stands with assist
6-7 months
crawls, creeps, pulls to stand at support, walks with assist
8-9 months
sidesteps/cruises with external support, stands alone, walking with one hand held
10-11 months
independent walking with high guard and wide BOS, lowers self with control from standing, may move in/out out squat position
12 months
newborn stepping emerges from a reflex; reflex disappears when higher neural centers in the cortex inhibit spinal motor centers; erect independent walking occurs when equilibrium and postural reflexes emerge
hierarchical model
locomotion occurs as a result of interactions between developing sensory, motor, perceptual respiratory, cardiac and anatomic systems in infant; neonatal stepping pattern disappears because of changes in the weight of infant limbs in the first few months of life
dynamic systems model
what are some unique challenges to gait development in children
- children are top heavy (head and trunk are large)
- lack motor experience (inability to fractionate movement)
- rapid physical growth requires ongoing adaptation
- early walking experiences occur over a variety of locations and surfaces
- motivation to walk varies
what are some key characteristics of early infant gait
- higher ratio of hip/knee flexion to keep COG lower
- no heel strike during initial loading response (flat footed)
- wide BOS
- arms held away from body (high guard)
- erratic joint motions (variable step rates and step lengths, inconsistent timing of muscle actions)
what are the two processes for learning how to walk
- control of balance
- refinement of locomotor pattern
when does control of balance occur
3-6 months after onset of walking
period of double limb support time decreases gradually as postural control improves; step length increases as step width decreases (gait velocity increases)
control of balance
do we have more stability when walking faster or slower
faster
when does refinement of locomotor pattern occurs
over 5 years after onset of walking
decreased hip flexion, anterior pelvic tilt and hip abd/ER during swing occurs by age
2 yrs
when does reciprocal arm swing become present in 75% of kids
3 yrs
when does mature knee pattern from initial contact to terminal stance observed by
4 yrs
when is push off seen
2 yrs
at what age does most muscle and movement patterns look very similar to adult gait cycle
7 yrs
progression of stair climbing
(depends on opportunity/access to stairs)
starts quadruped –> ascend with greater control –> standing will do step-to stepping before reciprocal stepping
when does reciprocal stepping emerge
3 yrs
progression of more advanced running/hopping motions
run –> gallop –> hop –> skip
is often described as an exaggerated form of walking except for a brief flight phase in each steps
running
at what age does running develop
2 yrs
at what age do children begin to hop and gallop
age 4 (galloping precedes hopping)
requires asymmetrical gait with unusual timing and force production in each limb
galloping
requires one limb balance reactions and additional force to lift the body off the ground
hopping
requires increased coordination and is most difficult to reproduce
skipping
navigation over and around obstacles on different surfaces and while performing other tasks requires 2 strategies
- reactive strategies
- proactive strategies
integration of postural responses into the gait cycle; children initially respond to perturbations with both an automatic postural response and a monosynaptic stretch reflex
reactive strategies
stepping to recover balance beings to develop in infants within ______ of walking experience and is refined by ___ of walking experience
1-3 months
6 months
ability to use sensory information from the environment to modify gait patterns in advance of encountering obstacles to gait may not emerge until 3-4 y/o and continues to mature up to age 9
proactive strategies
children develop feedback control of balance before feedforward control
- because you need experience for feedforward
until about age 6 children rely heavily on ______ from their feet and the support to modify gait pattern (bottom up control)
sensory cues
after age 7 children gain mastery control over the _____ in space and have increased vestibular and visual processing allowing for top-down control of gait
head position
balance between HS and quads is evident by age
2
swing phase activity of calf muscles disappears by age 2 resulting in unopposed activity of
anterior tibialis (heel strike pattern emerges)
_____ is directly proportional to walking speed at all ages
energy cost
children have a ____ energy expenditure during walking than teenagers and adults
higher
walking contributes to a child’s health by improving what
aerobic capacity, resting metabolic rate, body composition, fat metabolism
upright mobility increases what
bone mineral density
complex motor skill acquisition results in what; learning a complex motor skill results in what
- neuroplasticity and dendritic aboritization
- cortical organization and reorganization
independent mobility has impact on what aspects of development and what are examples
cognitive, perceptual, socioemotional
- visual attention to environment
- wariness of heights
- working memory
- object permanence
- transfer of information
- independent decision making
what are the phases of the gait cycle
initial contact, loading response, mid-stance, terminal stance, pre-swing, initial swing, mid swing, terminal swing
single limb cycle consists of two main phases and what are they
- stance phase: when the foot strikes the ground (60%)
- swing phase: when the foot leaves the ground (40%)
the last 10% of stance phases when both feet are touching the ground
double support
what phases of the gait cycle compose the stance phase
- initial contact
- loading response
- mid-stance
- terminal stance (40%)
- preswing
the instant the foot contacts the ground (usually at heel)
initial contact (0-2%)
the first interval of double limb stance when weight is transferred to the supporting limb
loading response (0-10%)
the first half of single limb support is initiated by limb toe off; COM progresses dynamic stability over a plantigrade foot
mid-stance (10-30%)
the second half os SLS; COM progresses anterior to the ankle joint axis towards the metatarsal axis; heel rise normally occurs
terminal stance (30-50%)
the second interval of double limb support when the support limb is unloaded in preparation for swing and weight is transferred to the other limb (the other limb is in initial contact)
pre-swing (50-60%)
what phases make up the swing phase and what type of support are they
single limb support
- initial swing
- mid-swing
- terminal swing
foot is lifted off the support surface and begins to advance forward; the contact limb is in the first 1/2 of midstance
initial swing (60-73%)
midpoint of the phase, minimal toe clearance is achieved, tibia reaches vertical; the contact limb is in late midstance and early terminal stance
mid-swing (73-87%)
final part of the phase, foot continues to advance forward in preparation for initial contact
terminal swing (87-100%)
how much clearance do we need to clear the toes during initial swing
2 cm
how much DF do we need for initial contact
5 deg
stabilizes the limb for weight acceptance and shock absorption and generates propulsive forces for continued motion
stance phase
reposition the limb to continue forward progression and clears the toes
swing phase
force exerted on body by surface being walked on
ground reaction force (GRF)
every action has an equal and opposite reaction
newton’s 3rd law
where is the GRF during initial contact and what muscles are firing
posterior to ankle, anterior to knee and hip
- hip: hip extensors working eccentrically to resist flexion, erector spinae eccentrically to resist trunk flexion
- knee: quad femoris eccentric to control knee flexion and prevent buckling
- ankle: DF eccentrically to slow PF (foot slap)
where is the GRF during loading response and what muscles are firing
posterior to ankle and knee, anterior to hip
- hip: hip extensors concentrically to extend hip, erector spinae resist flexion
- knee: after flat foot, quad fire concentrically to bring femur over tibia
- ankle: decrease DF; tib post, FHL, FDL fire eccentrically to control pronation
where is the GRF during midstance and what muscles are firing
anterior to ankle, moves posterior to anterior on knee, move anterior to posterior on hip
- hip: iliopsoas fires eccentrically to resist extension, glut med contracts to stabilize opposite hip
- knee: quad activity reduced, gastroc eccentrically to control excessive knee ext
- ankle: PF (GS and peroneal) fire eccentrically to control DF of tibia over fixed foot and control pronation
where is the GRF during terminal stance and what muscles are firing
anterior to ankle, anterior ot knee, posterior to hip
- hip: none
- knee: gastroc starts to fire concentrically to start knee flexion
- ankle: PF start to fire concentrically to prepare push off
where is the GRF during pre-swing and what muscles are firing
anterior to ankle, posterior to knee and hip
- hip: adductor longus, rectus femoris, iliopsoas
- knee: quads eccentrically
- ankle: PF/elastic recoil/concentric of PF
how much knee flexion is needed during gait
60 deg
where is the GRF during initial and mid-swing and what muscles are firing
no GRF bc foot not on ground
- hip: add longus to initiate hip flexion in pre-swing, rectus femoris later in pre-swing to flex hip while limiting knee flexion; iliacus and sartorius fire during initial swing and mid-swing; LHBF and SM late in mid-swing to decelerate limb
- knee: rectus femoris to decelerate knee flexion
- ankle: DF fire to clear toes
where is the GRF during terminal swing and what muscles are firing
no GRF
- hip: hip extensors to decelerate leg and prepare initial contact
- knee: vastii muscles fire in preparation for initial contact and counteract HS activity
- ankle: DF
ROM needed at hip during gait
- flex: 25 deg
- ext: 15 deg
- some rotation and add/abd required
ROM needed at knee during gait
- ext: full 0 deg
- flex: 60 deg (initial swing)
ROM needed at ankle during gait
- PF: 15 deg (preswing)
- DF: 10 deg (terminal stance); 5 deg to clear toes during swing phase
ROM needed at foot during gait
- great toe ext: 50 deg
at ankle/foot: initial contact made with forefoot
forefoot contact
at ankle/foot: initial contact made with forefoot and hindfoot
flatfoot contact
at ankle/foot: rapid PF after initial contact (heel strike); makes audible
foot slap
at ankle/foot: excessive inversion of calcaneous or forefoot in any phase
excessive inversion/pes cavus
at ankle/foot: excessive eversion of calcaneous or forefoot in any phase
excessive eversion/pes planus
at ankle/foot: inadequate 1st MTP ext in pre-swing
inadequate MTP ext
at ankle/foot: with or without hammer toes
excess IP flexion (clawed toes)
at ankle/foot: foot contact with ground during swing phase
toe drag
at ankle/foot: excess ankle PF of stance limb to help advance swing limb
contralateral vault
at knee: less than normal extension
inadequate extension/crouched gait
at knee: less than normal flexion
inadequate flexion/stiff legged gait
at knee: extension beyond neutral
hyperextension/back knee
at knee: rapid movement toward extension (not controlled)
extensor thrust
at knee: repeated alternating flex/ext (lack of control)
wobble
at knee: adduction of distal tibia relative to femur
varus/bow-legged
at knee: abduction of distal tibia relative to femur
valgus (knock-knee)
at hip: inadequate extension in stance phase
inadequate extension/crouched gait
at hip: less than normal flexion for phase
inadequate flexion
at hip: more than normal flexion in swing phase
excess flexion/steppage gait
at hip: position of femur with excessive rotation
medial/lateral rotation
at hip: abduction of femur beyond neutral
abduction
at hip: adduction of femur beyond neutral
adduction/scissoring gait
at hip: thigh abduction and flexion followed by adduction during swing phase
circumduction
at pelvis: >5deg drop of iliac crest of swing limb during stance on reference limb
contralateral drop/trendelenberg gait
at pelvis: elevation of iliac crest of reference limb above neutral during swing phase
hike
at pelvis: >5deg backward rotation during terminal stance and may continue t/o phases
excessive backward rotation/retracted pelvis
at pelvis: >5deg forward rotation during mid and terminal swing
excess forward rotation/protracted pelvis
at pelvis: any excessive tilt
excess ant/post tilt (apt/ppt)
lateral displacement of the pelvis occurs with each step forming a
sinusoidal curve
____ shoulder flexion occurs with ipsilateral terminal stance with ipsilateral pelvis rotated backward
maximal
as walking speed _____, total shoulder movement and arc of pelvis rotation increases
increases
use the natural shape of the ankle/foot bones to create momentum and smooth movement, it improve efficiency as energy is supplied by momentum
ankle-foot rockers
at initial contact when calcaneous contacts the surface; the loading response brings the tibia as forward as the knee flexes; the heel lever caused ankle PF 5 deg
heel rocker
during midstance the tibia rotates forward along the talocrural axis causing 5deg DF; the tibia progresses over the talus moving the GRF anterior to the ankle
ankle rocker
occurs in terminal stance when heel lifts off support surface and mid/hindfoot rotate about the extending MTP joints; ankle DF increases to 10 deg as tibia advances; also called roll off since PFs eccentrically control DF
forefoot rocker
during pre-swing, 1st ray extends 50 deg, ankle PF to 15deg, knee flexes to 40deg to prepare for swing
toe rocker
_______ of the achilles tendon follows eccentric contraction of PFs, this causes the achilles tendon 15 deg of PT as the limb is rapidly unloaded
elastic recoil
the number of steps taken during a specific time (steps/min) and what is the norms
cadence
M: 108 steps/min
F: 118 steps/min
walking speed =
stride length x 1/2 cadence
linear distance between 2 successive events on the same limb (initial contact) and what are the norms
stride length
M: 1.51 m
F: 1.32 m
stride length =
walking speed / 1/2 cadence
the linear distance between 2 successive events on opposite limbs and what is the norm
step length
.71m
the horizontal distance between 2 points on opposite limbs and what is the norm
step width
7-10 cm
the minimal linear distance from the hallux to the floor during swing phase and what is the norm
toe clearance
1.28 cm
the distance traverses over a specific time period (m/s or m/min) and what are norms
gait speed
M: 82m/min or 1.37 m/sec
F: 78m/min or 1.30 m/sec
gait speed =
distance / time
