Exam 1 lecture: gait cycle

Question 1

what is the line of progression?

Answer 1

best fit straight line b/t 2 contacts

Question 2

what is step, step length?

Answer 2

distance b/t 2 successive imprints (R –> L)

not a full gait cycle

Question 3

what is stride, stride length?

Answer 3

distance b/t a common spot on both feet

may not be the same from R –> L and L –> R

Question 4

what is a full gait cycle?

Answer 4

both limbs complete 1 “stride”

Question 5

what is a stride?

Answer 5

what happens from one imprint to the next on the same limb

not technically a gait cycle; one limb has undergone one full cycle, other is out of phase

Question 6

how much foot flare is considered acceptable in a normal walking gait?

Answer 6

5˚ - 7˚

Question 7

what happens to foot flare as cadence (speed) increases?

Answer 7

it decreases

Question 8

effects of too much toe out

Answer 8

increased stress on lower extremity –> injury

inefficient –> more muscle work, decreased stride length

Question 9

which is more common: toe in or toe out?

Answer 9

toe out

Question 10

what are the 2 phases of the gait cycle

Answer 10

swing and stance

Question 11

in RUNNING, how much of the gait cycle is swing? how much is stance?

Answer 11

60% swing, 40% stance

Question 12

in WALKING, how much of the gait cycle is swing? how much is stance?

Answer 12

40% swing, 60% stance

Question 13

what is stance phase?

Answer 13

foot is in contact w/ground; closed kinetic chain

Question 14

what is swing phase?

Answer 14

foot is not in contact w/ground: open kinetic chain

Question 15

when the speed of the gait cycle increases, there is an increase in these forces: (6)

Answer 15

compression
distraction
torsion
shear
bending
inertia

Question 16

why does compression force increase as speed increases?

Answer 16

increased speed of hitting the ground

Question 17

how does torsion increase as speed increases?

Answer 17

increased body twisting

Question 18

how can torsion cause injury?

Answer 18

when torsion increases beyond normal limits, tissue begins to break down –> increased demand on muscles and bones –> failure

Question 19

what are some problems that can cause increased torsion?

Answer 19

too much foot flare, too much pronation

Question 20

which force is most damaging?

Answer 20

shear

Question 21

how can bending help prevent injury?

Answer 21

changes the forces the body has to deal with, takes away initial compression forces as foot hits the ground

Question 22

how does muscle control help to prevent injury?

Answer 22

muscles interacting w/ground to act as shock absorbers contract more to control increased inertia w/increased velocity; convert energy into managable motions

Question 23

what increases injury risk?

Answer 23

increased ground reaction forces, increased muscle activity (esp. eccentrically)

Question 24

what are the 3 divisions of stance phase?

Answer 24

contact/foot strike
midstance
takeoff

Question 25

t or f: toe off is the same as take off

Answer 25

false. toe off is at the very end of take off.

Question 26

what is a closed kinetic chain?

Answer 26

distal end of limb is connected to a fixed object (aka the ground)

Question 27

what is it called when both feet are on the ground in different parts of stance phase?

Answer 27

double support | *this only occurs during WALKING*

Question 28

what is it called when both feet are in the air in different parts of swing phase?

Answer 28

float | *this only occurs during RUNNING*

Question 29

why is walking less injurious than running?

Answer 29

amount of muscle contraction running takes to control the action

Question 30

t or f: during contact, the foot lands directly under the center of gravity.

Answer 30

false. the foot lands ahead of the center of gravity.

Question 31

what are the important functions of contact (phase)?

Answer 31

absorb shock | adapt to ground forces

Question 32

what is pronation?

Answer 32

medial rotation of the foot

Question 33

t or f: the foot can be pronating in a supinated position or pronating in a pronated position.

Answer 33

true

Question 34

what are the 2 important joints of pronation?

Answer 34

subtalar and midtarsal jts.

Question 35

what is it called when the weight begins to transfer forward on the foot?

Answer 35

heel rocker

Question 36

what is the calcaneus doing in pronation?

Answer 36

eversion, dorsiflexion relative to talus

Question 37

t or f: talus dorsiflexes only after pronation has begun.

Answer 37

false. the talus dorsiflexes before pronation of foot occurs., then begins plantar flexion when pronation begins.

Question 38

how does the foot land when walking at contact?

Answer 38

2˚ supinated

Question 39

what initiates pronation of the foot?

Answer 39

plantar flexion of the talus

Question 40

what is the ideal pronation ROM?

Answer 40

6˚ - 10˚

Question 41

what is the clinical normal pronation ROM?

Answer 41

5˚ - 15˚

Question 42

what happens to the tibia and femur during contact?

Answer 42

internal rotation

Question 43

why is it important the the tibia and femur internally rotate?

Answer 43

reduces torque (moves in the same direction as foot; opposite directions would create torsion)

Question 44

which 2 types of stresses are most deleterious to connective tissue?

Answer 44

shear, torsion

Question 45

why is torsion so damaging?

Answer 45

wears down collagen fibers quickly

Question 46

how to calcaneus and talus motion differ?

Answer 46

talus moves w/leg, not at ankle | calcaneus moves w/foot

Question 47

when is rearfoot strike utilized?

Answer 47

walking, jogging/slow running

Question 48

when is forefoot strike utilized?

Answer 48

fast running

Question 49

what muscle eccentrically controls plantar flexion at the ankle joint and pronation of the foot?

Answer 49

tibialis anterior

Question 50

when does the foot/talus plantar flex during rearfoot strike?

Answer 50

after the heel initially strikes the ground

Question 51

what large thigh msl does the tibialis anterior assist?

Answer 51

quadriceps

Question 52

in forefoot strike, when does the foot dorsiflex?

Answer 52

after the metatarsal heads first strike the ground - heel moves toward ground

Question 53

initial foot strike is pronated or supinated?

Answer 53

2˚ - 4˚ supinated

Question 54

t or f: pronation occurs much faster during forefoot strike than rearfoot strike

Answer 54

true.

Question 55

what muscles control dorsiflexion?

Answer 55

gastroc-soleus

Question 56

what muscles control pronation?

Answer 56

tibialis anterior and posterior

Question 57

during midstance, where is the center of gravity?

Answer 57

directly over the stance limb

Question 58

what position is the foot in during midstance?

Answer 58

pronated

Question 59

t or f: the foot is pronating during midstance

Answer 59

false. the foot is pronated, but pronation should be done by the time midstance begins

Question 60

what is the foot doing (i.e. what motion)?

Answer 60

supinating (a shift back toward neutral)

Question 61

when does most pronation occur?

Answer 61

contact

Question 62

how long does midstance last?

Answer 62

from foot flat to heel lift when walking

Question 63

what is the ankle rocker?

Answer 63

center of gravity/leg continues to move forward w/foot planted on the ground --> ankle undergoes rocking motion

Question 64

what are the leg and thigh doing during midstance? why?

Answer 64

externally rotating to reduce torque

Question 65

when should heel lift occur?

Answer 65

after the swing limb passes the stance limb; | when walking: heel lift same time as heel strike of opposite limb.

Question 66

why might the heel lift early?

Answer 66

tight stance limb gastrocsoleus/achilles tendon

Question 67

where is the center of gravity during take off?

Answer 67

anterior to stance foot

Question 68

what muscles lift the heel?

Answer 68

gastrocsoleus

Question 69

what does the calcaneus do during take off?

Answer 69

inverts to complete rearfoot supination

Question 70

what muscle inverts the calcaneus?

Answer 70

tibialis posterior

Question 71

when is the foot the most rigid?

Answer 71

during supination - at take off (except toes)

Question 72

why are the toes not rigid during take off?

Answer 72

to prevent injury

Question 73

what allows the foot to roll onto the ball of the foot?

Answer 73

passive toe extension

Question 74

what happens to the plantar fascia when toes extend? why?

Answer 74

plantar fascia tenses to help maintain arch | *hallux is particularly important for this*

Question 75

what is the metatarsal break?

Answer 75

oblique angle of metatarsal heads

Question 76

what is toe off?

Answer 76

the very end of take off

Question 77

t or f: supination occurs at end of take off.

Answer 77

false. slight pronation occurs at end of take off

Question 78

why does the foot pronate at the end of take off?

Answer 78

to increase load bearing on 1st & 2nd metatarsals - 4th and 5th are too weak to handle weight of take off

Question 79

which ray is most important to forefoot control just before take off?

Answer 79

1st ray

Question 80

what muscles are important to 1st ray stabilization & control of pronation just before toe off? (5)

Answer 80

``` peroneus longus flexor hallucis longus flexor hallucis brevis adductor hallucis abductor hallucis ```

Question 81

what happens to the tibia and femur during take off?

Answer 81

externally rotate

Question 82

what happens if there is too much pronation late in take off?

Answer 82

late pronation --> foot tries to medially rotate, leg and body try to laterally rotate --> torsion --> stress fractures of tibia, pelvis, femur, etc., stress on jts, may affect spine

Question 83

t or f: all flat feet over pronate

Answer 83

false.

Question 84

what does peroneus longus do during take off?

Answer 84

lifts cuboid and lateral foot depresses & plantar flexes 1st ray maintains contact b/t ground and 1st metatarsal head

Question 85

what gives peroneus longus the most leverage? (pronated vs. supinated foot)

Answer 85

supinated foot

Question 86

what is a possible cause of posterior shin splints?

Answer 86

excessive pronation at end of stance phase --> inhibited peroneus longus --> tibialis ant. & post. fatigue

Question 87

what are the 3 divisions of swing phase?

Answer 87

initial swing midswing terminal swing

Question 88

what division of swing phase is most prominent in walking?

Answer 88

midswing

Question 89

what division(s) of swing phase is accentuated in running?

Answer 89

initial and terminal swing

Question 90

what does the tibia do during initial swing?

Answer 90

internally rotates

Question 91

what does the hip do during initial swing?

Answer 91

extends and externally rotates

Question 92

what muscles eccentrically decelerate @ the hip and knee?

Answer 92

hip flexors

Question 93

t or f: there is more initial swing in walking than there is in running.

Answer 93

false. initial swing is drastically increased during running.

Question 94

what is the problem with over-striding?

Answer 94

more stretch on hip flexors --> more potential for strain injuries

Question 95

when in initial swing, what is the opposite limb doing when running vs. when walking?

Answer 95

running: terminal swing walking: end of foot strike

Question 96

what is the bowling ball effect?

Answer 96

momentum pulls body forward when leg swings forward | *hip flexors very important for this*

Question 97

when does midswing start?

Answer 97

when leg starts swinging forward

Question 98

at the end of midswing, what muscles eccentrically slow the forward swinging limb at the hip and knee?

Answer 98

gluteals and hamstrings

Question 99

what position is the foot in during midswing?

Answer 99

neutral/slightly dorsiflexed (prevent foot drag)

Question 100

does the hip internally or externally rotate during midswing?

Answer 100

internally rotate

Question 101

when does terminal swing begin?

Answer 101

when foot begins moving backward (toward ground to begin heel strike)

Question 102

what muscles are responsible for terminal swing?

Answer 102

hip extensors and knee flexors

Question 103

t or f: foot flare and amt of rearfoot inversion at next foot strike is determined during swing phase

Answer 103

true.

Question 104

when are hamstrings at greatest tension?

Answer 104

terminal swing

Question 105

what factors can increase risk of hamstring injury?

Answer 105

decreased flexibility and strength of hamstrings

Question 106

t or f: foot rotates in same direction as leg and thigh

Answer 106

true. this is to reduce torsion on ankle jts.

Question 107

what could change the direction of rotation in the foot?

Answer 107

over pronation