Gait Exam I

Define gait

locomotion with periods of loading and unloading

Differentiate a gait cycle versus a step cycle

gait is period of heel strike to next heel strike of same foot, step is heel strike of one foot to heel strike of other foot

How many steps are in a stride?

dos

What is the passenger unit? What does it control?

pelvis, head, neck, trunk, arms - helps control COM

What is the locomotor unit? Function?

pelvis and lower limbs - propulsion

Where is the COM relative to the BOS in dynamic stability?

outside of BOS

What are the three components of the initial step and describe them

preparation: weight shift to swing limb
weight shift: shift to stance limb
progression: pick up swing limb

What is the purpose of what occurs during the preparation phase of the initial step?

gain momentum

What are the foot rockers in the stance limb?

heel, then ankle, forefoot, toe

What are the propulsive forces during the step and at what phase do they mostly occur?

concentric muscle activity, during swing phase

What joints do shock absorption occur at?

hip, knee, ankle

What is the primary way of shock absorption in gait?

eccentric control

What is the goal of center of gravity alignment modulation?

keep the COM from moving excessively to conserve energy

What is the lowest point of vertical displacement and at what percentages of the gait cycle?

midpoint of double limb support - 5% and 55% in cycle

What is the highest point of vertical displacement and at what percentages of the gait cycle?

midpoint of single limb support at 30% and 80%

What is the normal vertical displacement total during the gait cycle?

5 cm

How many sine waves in vertical versus horizontal displacement in a gait cycle?

vertical - 2
horizontal - 1

At what points do maximum displacement occur in horizontal plane during gait cycle?

midpoint ipsilaterally (30%) and midpoint contralaterally (80%)

What is normal value for total horizontal displacement?

4 cm

Minimizing vertical displacement of the COM involves adjustments in what plane of motion? At what joints?

sagittal plane at hip, knee, ankle

What three things does the body do to minimize horizontal displacement of CoM

frontal plane motion at the pelvis/hips, physiologic knee valgus, and momentum inertia

Physiologic knee valgus produces what advantage in gait?

decreases step width

Do we use momentum to decrease or increase inertia in horizontal displacement?

decrease

What percentages of the gait cycle do stance and swing occur for the reference limb?

stance - 0-60%
swing - 61-100%

At what periods of the gait cycle do double limb support occur?

from 0-10% and 50-60%

What is the relationship between gait speed and double limb support time?

as gait speed increases, double limb time decreases, and vice-versa

T/F we have no double limb support during running

True

At what periods do single limb support occur in gait cycle?

one foot 10-50%, other foot 60-100%

What is the measure of stride length and what is the normal distance?

distance from heel strike to same heel strike, normal is 1.44 m

What is measure of step length and what is it named according to?

length of one heel strike to other foot heel strike, named in reference to lead heel

*norm =.72 m*

What is the measure of step width? What is normal values?

medial-lateral distance between heels, normal value is 7-9 cm

What is the measure of foot angle and what is normal value?

angle of foot relative to line of progression, normal is 7 degrees (laterally)

What is cadence and how do you measure?

step rate, number of steps taken in a minute

What is the normal cadence for males vs females?

males - 110
females - 116

How could you measure step time (2)?

minutes per step, or take reciprocal of cadence

How do you measure walking speed and what is normal value?

cadence multiplied by step length to give distance covered per minute, normal is 1.37 m/s or 3 mph

What are two ways to increase walking speed?

increase cadence or increase step/stride length

What are the three functional tasks of the gait cycle? What percentages of the cycle do they take up?

weight acceptance (0-10%), single limb support (10-50%), limb advancement (50-100%)

What does the weight acceptance functional task consist of?

consists of shock absorption, initial limb stability, and preservation of forward progression

What does the single limb support functional task consist of?

body weight support and preservation of forward progression

What does the limb advancement functional task consist of?

limb elevation, limb forward advancement, preparation for stance

How does the limb advancement functional task and the swing phase differ?

limb advancement starts at 50% of cycle with limb still in contact (preswing), swing starts at 60% when toe off occurs

What are the phases of the stance phase in order, and what percentages of the gait cycle do they make up?

initial contact: 0-2%
loading response: 0-10%
mid-stance: 10-30%
terminal stance: 30-50%
preswing: 50-60%

What are the two phases within the stance phase in which single limb support occurs

mid-stance and terminal stance

What event marks the initial contact phase of the stance phase, and what functional task is it a part of?

heel strike, weight acceptance

What events mark the loading response phase of stance? What functional task is it a part of?

initial contact to opposite limb toe off, part of weight acceptance

What events mark the mid-stance phase of stance? What functional task is it a part of?

toe off of opposite limb to heel rise of reference limb. part of single limb support

What events mark the terminal stance phase of stance? What functional task is it a part of?

heel rise of reference limb to initial contact of opposite limb. part of single limb support

What events mark the pre-swing phase of stance? What functional task?

opposite limb contact to toe off of reference limb, task is limb advancement

What phases make up the swing phase and at what percentages of the gait cycle?

initial swing: 60-73%
mid-swing: 73%-87%
terminal swing: 87%-100%

What events mark the initial swing phase? What functional task?

toe off reference limb to adjacent feet. part of limb advancement

What events mark the mid-swing phase? What functional task is it a part of?

feet adjacent to tibia vertical. part of limb advancement

What events mark the terminal swing phase? What functional task?

tibia vertical to initial contact of reference limb. part of limb advancement

What are joint kinematics versus joint kinetics?

kinematics - angular position/displacement (ROM)
kinetics - external/internal moment arms (torques)

Where is the GRF in A/P horizontal plane during initial contact and toe off?

IC - posterior direction
TO - anterior direction

What are peak values of GRF during the stance phase in vertical, A/P, and M/L planes?

vertical - 120%
A/P - 20%
M/L - 5%

What is the center of pressure (CoP)? Where is it located during initial contact, midstance, terminal stance, and toe-off?

Point of application of GRF:

IC: midpoint of heel
MSt: lateral midfoot region
TSt: medial forefoot
TO: great toe

How does JRF and GRF and joint moments change with increased movement speed?

all increased (due to increased acceleration)

How do you measure torque?

force * perpendicular moment arm

How do you capture muscle activity and what does it measure?

EMG, measures motor recruitment signals (voltage) as a function of time

What is ROM, torque demand, muscle activity, and functional significance of initial contact?

ROM - neutral or slight PF
TD - external plantar flexion
MA - internal concentric dorsiflexion
FS - position foot for loading response

What is the ROM, torque demand, muscle activity, and functional significance for loading response at the ankle?

ROM - 5 degrees rapid plantar flexion
TD - external plantarflexion (decreased at end)
MA - eccentric pretibial muscles
FS - preserve forward momentum via HEEL ROCKER

By what part of stance does the GRF move anterior to the ankle?

mid-stance

What is the ROM, torque demand, muscle activity, and functional significance of mid-stance at the ankle?

ROM - 5 degrees DF
TD - external dorsiflexion
MA - eccentric plantarflexors
FS - preserve forward momentum via ankle rocker

What is the fulcrum at mid stance?

ankle

At what stage of stance is the maximum dorsiflexion torque demand?

terminal stance

At what stage of stance is muscle activity at max demand at the ankle?

terminal stance, plantarflexors max eccentric

What is the ROM at the ankle and MTPs, torque demand, muscle activity, and functional significance of terminal stance?

ROM - ankle at 10 degrees DF, MTPs at 30 degrees ext
TD - max external dorsiflexion
MA - mac eccentric plantarflexors
FS - max forward progression via forefoot rocker

What is the fulcrum during terminal stance?

forefoot (MTPs)

What stance provides the critical component of optimal step length of the opposite limb?

trailing limb posture that occurs in terminal stance

What is the ROM of preswing at the ankle and MTPs? What is the total arc of the ankle from terminal stance to preswing?

ankle - @ 15 degrees PF, MTPs - 60 deg ext.
total arc at ankle - 25 deg (10 deg DF - 15 PF)

What is the fulcrum during pre-swing?

toe rocker = anteromedial forefoot and great toe

What is the torque demand, muscle activity, and functional sig during preswing at the ankle?

TD - minimal because weight is mainly on the other foot
MA - PFs rapidly decrease
FS: PF assists with KF and swing advancement via toe rocker

What is the moving force for the total arc undergone during pre-swing?

passive tension in gastroc causes an elastic recoil effect that thrusts the tibia forward

What is the ROM, torque demand, muscle activity, and functional significance of initial swing at the ankle?

ROM - 5 degrees plantarflexion
TD - external PF (gravity)
MA - concentric DF
FS - clearance of foot

What is ROM, torque demand, muscle activity, and significance of mid swing at the ankle?

ROM - dorsiflexes to 0
TD - external PF (gravity)
MA - concentric DF
FS - clearing of foot

What is ROM, torque demand, muscle activity, and functional significance of terminal swing

ROM - remains neutral
TD - external PF (gravity)
MA - isometric DF
FS - assure heel contact

What is the ROM, torque demand, and muscle activity of loading response through midstance in the frontal plane? (0-30%)

ROM moves from 2 degrees inversion to 2-3 eversion
TD - external eversion torque
MA - eccentric tib ant. and post. (inverters)

What is the functional significance of loading response through midstance in the frontal plane?

subtalar pronation assists with shock absorption

Where is the GRF relative to the ankle during frontal plane loading response through midstance? What does this cause?

lateral to ankle causing eversion

What is the ROM, torque demand, and muscle activity for terminal stance through pre-swing in the frontal plane? (30-60%)

ROM - 2-3 eversion to 4-6 inversion
TD - external inversion torque (medial to ankle)
MA - tib. post, soleus, peroneals

What is the functional significance of terminal stance through pre-swing in the frontal plane?

inversion/supination provides a rigid lever for push off

What is the ROM, torque demand, and muscle activity for initial swing through terminal swing in the frontal plane? (60-100%)

ROM - return back to slight inversion (2-3 deg)
TD - negligible
MA - pretibial and ankle inverters (eccentrically)

what is the functional significance of initial swing through terminal swing in the frontal plane at the ankle?

prepare foot for initial contact

Why is vertical GRF greater than body weight?

acceleration forces

If there is a GRF lateral to the ankle, which position would the foot be in?

eversion

What type of muscle activity is important in foot clearance during initial and midswing at the foot?

concentric dorsiflexors

At initial contact for the knee, what is the ROM, TD, MA, and Fs?

ROM - 0-5 deg flexion
TD - external extension
MA - quad/hammy co-contraction
FS: stabilization of the knee for LR

At loading response for the knee, what is the ROM, TD, and MA?

ROM - 20 deg of flexion
TD - external flexion torque
MA - eccentric quads

What is the functional significance of loading response at the knee in the sagittal plane?

shock absorption, limb stability, forward progression

By the end of loading response, the external torque at the knee is in the direction of _________ and the active muscle group is the _________ with a __________ contraction

flexion, quads, eccentric

By the end of loading response, the GRF is ____ to the knee creating an external torque in the direction of _____

posterior; flexion

How does the ROM change at the knee in mid stance

moves from 20 deg flexion to 0-5 deg flexion

What is the TD and MA at the knee in mid stance in sagittal plane

TD - from flexion to external extension
MA - concentric quads until BW is in front of the ankle, then gastroc and soleus kick in

What maintains knee stability during midstance? (functional sig)

gastroc and soleus and the external extension torque

T/F: The quads are active during terminal stance?

FALSE - our body weight/gastroc soleus helps to keep the knee extended

What is the ROM, TD, and MA, and functional significance during terminal stance at the knee?

ROM - max extension
TD - external extension (peaks and then decreases)
MA - gastroc and soleus keep knee extended
FS - knee stability, forward prog, trailing limb posture

What muscle prevents hyperextension during terminal stance at the knee?

biceps femoris - short head

What is the ROM at pre-swing at the knee?

moves from max extension to rapid 40 degrees flexion

What is the torque demand and MA at the knee during pre-swing?

TD: external flexion due to ankle plantarflexion aka "interaction torque"
MA: rectus femoris (to restrain KF), minimal gracilis