Gait Cycle

Question 1

Is this force advantage/ disadvantage? If the fulcrum is closer to the effort?

Answer 1

force disadvantage

Question 2

Is this force advantage/ disadvantage? If the fulcrum is closer to the load?

Answer 2

force advantage

Question 3

Which class of lever is force advantage? force disadvantage?

Answer 3

force advantage= 2nd class lever 
force disadvantage= 3rd class lever

Question 4

give an example of a 1st class lever.

Answer 4

Ex. joint between head and 1st vertebrae

Ex. scissors, pliers, see-saw

Question 5

give an example of a 2nd class lever.

Answer 5

Ex. wheelbarrow, stapler, bottle opener, nutcracker

Ex. standing on tiptoes

Question 6

give an example of a 3rd class lever

Answer 6

Ex. biceps curl

Ex. fishing rod, tweezers, tongs

Question 7

What is Newton’s 1st law of motion?

Answer 7

(law of inertia)
a particle at rest , or moving in a straight line with a constant velocity, will remain in its state provided it is not subjected to an unbalanced force

Question 8

what is Newton’s 2nd law of motion?

Answer 8

(law of acceleration)
a particle acted upon by an unbalanced force experiences an acceleration that has the same direction as the force and a magnitude that is directly proportional to the force ; (F=ma)

Question 9

what is Newton’s 3rd law of motion?

Answer 9

(law of action-reaction)

the mutual forces of action and reaction between two particles/bodies are equal, opposite, and co-linear.

Question 10

explain this mechanical analysis method: direct dynamics (forward mechanics).

Answer 10

mechanical analysis of a system that determines movement from forces
Ex. using force plates to record forces

Question 11

explain this mechanical analysis method: inverse dynamics.

Answer 11

mechanical analysis of a system that determines force from movement
Ex. using video-based motion analysis

Question 12

what is the frontal plane movement for ankle, knee, and hip during the gait cycle?

Answer 12

ankle- inversion
knee- valgus
hip- abduction

Question 13

what percentage of the gait cycle is spent in stance phase?

Answer 13

60%

Question 14

what percentage of the gait cycle is spent in swing phase?

Answer 14

40%

Question 15

what percentage of the gait cycle is spent in double support? and when?

Answer 15

20% - there are 2 periods: 0-10% and 50-60%

Question 16

what percentage of the gait cycle then is spent in single-support?

Answer 16

80%

Question 17

what is normal gait speed?

Answer 17

1.4 m/s (3mph)

Question 18

what is normal step rate?

Answer 18

1. 9 steps/s (110 steps/min)

Question 19

what is normal step length?

Answer 19

72 cm (28 inches)

Question 20

what is the term for the sequence of events taking place between successive heel contact of the SAME foot?

Answer 20

stride (or gait cycle)

Question 21

what is the term for the sequence of events that occurs with successive heel contacts of the OPPOSITE foot?

Answer 21

step

Question 22

what is stride length?

Answer 22

distance btwn two successive heel contacts of the SAME foot

Question 23

what is step length?

Answer 23

the distance btwn two successive heel contacts of DIFFERENT feet
*recall that normal step length is 72 cm (28 in)

Question 24

what is step width?

Answer 24

lateral distance btwn the heel centers of 2 consecutive foot contacts
*normal step width is 7-9cm

Question 25

what is foot angle?

Answer 25

"the degree of turnout"; the angle between the line of progression of the body and the long axis of the foot *normal foot angle is about 7 degrees

Question 26

name the temporal descriptors of gait.

Answer 26

cadence (or step rate) stride time step time

Question 27

what is cadence?

Answer 27

of steps per minute

Question 28

what is stride time?

Answer 28

the time for a full gait cycle

Question 29

what is step time?

Answer 29

the time for completion of a right or left step

Question 30

of all the spatial and temporal measures of gait, what is the best measure of an individual's walking ability?

Answer 30

walking speed

Question 31

all measurements of gait depend on what?

Answer 31

walking speed

Question 32

what are 2 strategies to increase walking speed?

Answer 32

1. increasing stride or step length | 2. increasing cadence

Question 33

which part of the gait cycle is affected when gait speed increases?

Answer 33

double-limb support (time spent in this phase will DECREASE)

Question 34

what happens to % of gait cycle spent in double limb support as gait speed increases?

Answer 34

% of gait cycle spent in double-limb support DECREASES

Question 35

what happens to stride length in the elderly?

Answer 35

stride length decreases

Question 36

what happens to stride length with increased speed?

Answer 36

stride length increases

Question 37

what happens to double support time with increased speed?

Answer 37

decreased double support time

Question 38

what happens to double support time in the elderly or in patients with balance disorders?

Answer 38

double support time increases

Question 39

what is considered slow speed/cadence?

Answer 39

<70 steps/min

Question 40

what is consdiered fast speed/cadence?

Answer 40

>120 steps/min

Question 41

what is typical/comfortable speed?

Answer 41

80-110 steps/min

Question 42

what are the 2 reduction of energy mechanisms to reduce vertical excursion by limiting downward displacement of CoM?

Answer 42

1. horizontal plane pelvic motion | 2. sagittal plane ankle motion

Question 43

what are the 2 reduction of energy mechanisms to reduce vertical excursion by limiting upward displacement of CoM?

Answer 43

1. stance phase knee flexion | 2. frontal plane pelvic rotation

Question 44

what is the mechanism that reduces medial-lateral excursion to save energy?

Answer 44

frontal plane hip rotation- reducing step width

Question 45

How do women compare to men in terms of walking speed, step length, and cadence?

Answer 45

women exhibit a slower walking speed, shorter step length, and faster cadence than men.

Question 46

When is minimum and maximum kinetic energy reached in the gait cycle?

Answer 46

min. KE is reached at mid-stance for both legs (30% and 80% of gait cycle ) max. KE is reached at double-limb support (5% and 55%)

Question 47

when is minimum and maximum potential energy reached in the gait cycle?

Answer 47

min. PE is reached at double-limb support (5% and 55%) | max. PE is achieved when CoM reaches its highest points (30 and 80%)