Gait Cycle

Question 1

the fundamental component of human locomotion

Answer 1

the gait cycle

Question 2

one complete gait cycle starts/ends

Answer 2

anatomical interactions occurring
start = moment foot first contacts the ground
end = moment same foot again makes ground contact with next step

any event can actually be chosen, but initial contact most convenient

Question 3

2 phases of gait cycle

Answer 3

stance + swing

Question 4

stance phase

Answer 4

lower extremity contacting the ground

AKA support phase or contact phase
initial contact to toe off

Question 5

swing phase

Answer 5

lower extremity is swinging through the air preparing for the next impact

Question 6

typical gait cycle duration and phase timing when walking

Answer 6

1 second duration

0. 6s stance
1. 4s swing

Question 7

3 subdivisions of stance phase

Answer 7

contact, midstance, propulsive period

Question 8

open-chain motions

Answer 8

swing phase

distal end of kinetic chain freely mobile

Question 9

closed-chain motions

Answer 9

stance phase

distal end of kinetic chain is fixed by ground-reactive forces

Question 10

walking % stance phase contact/midstance/propulsive period

Answer 10

contact = 27% (0-27%)
midstance = 40% (27-67%)
propulsive period = 33% (67-100%)

Question 11

running % stance phase contact/midstance/propulsive period

Answer 11

contact = 20% (0-20%)
midstance = 25% (20-45%)
propulsive period = 55% (45-100%)

Question 12

contact period

Answer 12

first part of stance phase

beginning at touchdown and ending when entire forefoot makes ground contact

Question 13

midstance period

Answer 13

second part of stance phase

body’s center of mass is “vaulting” over the stance phase foot

Question 14

propulsive period

Answer 14

final part of stance phase

beginning with heel leaving the ground and ending when tips of the phalanges no longer make ground contact

Question 15

stance phase periods % of entire gait cycle

Answer 15

contact = 18% (0-18%)
midstance = 24% (18-42%)
propulsive period = 20% (42-62%)

Question 16

keys (determinants) to metabolically efficient gait

Answer 16

pelvic rotation
pelvic tilt
knee flex/ext during stance
hip-ankle-knee interactions
lateral pelvic displacement

Question 17

in terms of energy: metabolically efficient gait

Answer 17

translate center of mass through space along path requiring least expenditure of energy

flattening of the pathway of the center of mass through space

Question 18

is having a flat pathway of the center of mass through space best

Answer 18

no; metabolically expensive (e.g. exaggerated knee flexion)

Question 19

defining difference between walking and running

Answer 19

center of mass during midstance
walking = high point
running = low point

Question 20

can airborne phase be used to distinguish walking from running

Answer 20

no; slow running has no airborne phase

Question 21

Weber paradox

Answer 21

when a muscle is fully stretched or shortened, contact between the muscle filaments is diminished and the muscle is weakened

Question 22

how does Weber paradox apply to gait

Answer 22

explaining walk-run transition preferences; walking slowly, running fast preferred over walking quickly and running slowly

Question 23

2 requirements for initiation of gait cycle

Answer 23

1 postural adjustment (interactions between proprioceptive and motor systems)
2 motor commands for volitional movement

Question 24

what makes initiation of gait cycle complex

Answer 24

motor circuits for postural adjustments and motor commands for volitional movement function independently

Question 25

2 pitfalls of "normal" gait

Answer 25

1 needs to be chose for the individual (e.g. elderly female vs physically fit young man) 2 differing from normal does not necessarily mean undesirable or requiring correction

Question 26

7 major events during gait cycle

Answer 26

``` 1 initial contact 2 opposite toe off 3 heel rise 4 opposite initial contact 5 toe off 6 feet adjacent 7 tibia vertical ```

Question 27

7 periods during gait cycle

Answer 27

``` 1 loading response (stance) 2 mid-stance 3 terminal stance 4 pre-swing (stance) 5 initial swing 6 mid-swing 7 terminal swing ```

Question 28

cycle time

Answer 28

duration of a complete gait cycle

Question 29

double support

Answer 29

initial contact for one foot occurs while other foot is still on the ground AKA double limb stance

Question 30

single limb stance

Answer 30

during swing phase on the left side, only the right foot is on the ground AKA right/left single support

Question 31

leading leg in double support

Answer 31

leg in front in loading response AKA braking double response, initial double support, weight acceptance

Question 32

trailing leg in double support

Answer 32

leg behind in pre-swing AKA weight release or second/terminal/thrusting double support

Question 33

phase that occurs in some forms of running, differing from walking

Answer 33

flight phase AKA float, double-float, non-support phase replaces double support phase; neither foot is on ground

Question 34

stride length (meters)

Answer 34

distance between two successive placements of the SAME foot consists of two step lengths (L/R)

Question 35

step length (meters)

Answer 35

distance one foot moves in front of another; DIFFERENT feet

Question 36

step length in pathological gait

Answer 36

typically different between R/L e.g. one foot takes a step forward, the other is brought up beside it, step length = 0 or even a negative value

Question 37

stride length step length in pathological gait

Answer 37

always the same L/R unless individual walking around a curve (inside leg shorter)

Question 38

drawback to stride definition

Answer 38

non-pathological gait cycle = consists of one step by each foot some pathological cycles = consists of HOPPING on same foot while other foot is in the air

Question 39

walking base (millimeters)

Answer 39

side-to-side distance measured between the line of the two feet usually measured at midpoint of back heel, but sometimes below center of ankle joint AKA stride width or base of support

Question 40

walking base = 0

Answer 40

tandem gait = one foot placed directly in front of the other while walking

Question 41

toe out/in (degrees)

Answer 41

angle between the direction of progression and a reference line on the sole of the foot (typically midline of foot, judged by eye)

Question 42

utilized coefficient of friction

Answer 42

ratio of horizontal to vertical forces acting on foot; determines if foot slips (utilized coefficient > actual coefficient between foot/ground) 0.35-0.40 generally sufficient to prevent slippage

Question 43

cadence

Answer 43

number of steps taken in a given time measure of half cycles (bc two steps in a cycle)

Question 44

speed of walking (m/s)

Answer 44

distance covered by whole body in a given time

Question 45

step factor

Answer 45

step factor = step length / leg length account for differences in size; speed may be expressed in statures per second

Question 46

walk ratio

Answer 46

walk ratio = step length / step rate

Question 47

butterfly diagram

Answer 47

representation of ground reaction force vector at 10 ms intervals progressing from L to R

Question 48

redundancy of muscular system

Answer 48

if a particular muscle cannot be used, its functions may be taken over by another muscle or group of muscles

Question 49

5 main functions of walking gait

Answer 49

1 support head, arms, TRUNK via semirigid lower limb 2 maintain upright posture + BALANCE 3 control FOOT to clear obstacles and gently land (eccentric) 4 generate mechanical energy (concentric) to influence VELOCITY 5 SHOCK ABSORPTION and stability, reduce forward velocity of body (eccentric)

Question 50

3 functional tasks required in gait, which is why patterns tend to be variable pre-7 yrs

Answer 50

1 forward progression in a range of speeds 2 body balanced alternately on each limb 3 support of upright body

Question 51

3 ways to measure different aspects of gait analysis

Answer 51

1 force platforms (ground reaction forces) 2 electromyography (muscle activity) 3 high-speed video motion analysis system (movement)

Question 52

spatial descriptor gait

Answer 52

Foot in space stride length, step length, step width, foot angle

Question 53

temporal descriptor gait

Answer 53

Foot in time cadence, stride time, step time