Biomechanics exam 3

Question 1

Initial contact CE

Answer 1

heel first contact

Question 2

loading response CE

Answer 2

hip stability, controlled knee flexion, ankle pf

Question 3

midstance CE

Answer 3

controlled tibial advancement

Question 4

terminal stance CE

Answer 4

ankle locked in DF with heel rise in trailing limb

Question 5

preswing CE

Answer 5

passive knee flexion to 40 deg

Question 6

initial swing CE

Answer 6

knee flexion to 60 hip flexion to 15

Question 7

midswing CE

Answer 7

further hip flexion to 25, ankle DF to 0

Question 8

terminal swing CE

Answer 8

knee ext to neutral

Question 9

what are the two functional tasks in stance phase?

Answer 9

weight acceptance and single limb support

Question 10

what is the functional task in swing phase?

Answer 10

swing limb advancement

Question 11

muscle activity during IC

Answer 11

pretibials, hip extensors

Question 12

muscle activity during LR

Answer 12

pretibials, quads, hip extensors and abductors

Question 13

muscle activity during MSt

Answer 13

calf, quads

Question 14

muscle activity during TSt

Answer 14

calf

Question 15

muscle activity during PSw

Answer 15

minimal add longus

Question 16

ISw

Answer 16

pretibials, 2 jt flexors, short head of biceps, hip flexors

Question 17

MSw

Answer 17

pretibials, short head biceps, hip flexors then extensors

Question 18

TSw

Answer 18

pretibials, quads, hamstrings then glutes

Question 19

what is cycle time measured in? (units)

Answer 19

seconds/steps

Question 20

what is cycle time measured in? (units)

Answer 20

steps/second

Question 21

compared to adults, a childs stride length is ____?

Answer 21

shorter

Question 22

compared to an adult, a childs cadence is ____?

Answer 22

faster

Question 23

compared to an adult, a childs gait speed is___?

Answer 23

slower

Question 24

when does a childs gait kinematics look like an adult? (age)

Answer 24

approximately 3 or 4

Question 25

how would you normalize data if you were comparing childrens gait to adults (like stride length and speed)?

Answer 25

divide by leg length or total height (specifically for speed or stride length)

Question 26

what happens if your joint moments don’t counteract ground reaction forces?

Answer 26

you will fall to the ground

Question 27

what joint motion does the GRF want to cause the ankle, knee, and hip to do at heel strike?

Answer 27

ankle PF, knee flexion, hip flex

Question 28

what do joint moments refer to (definition so to speak)

Answer 28

the motion produced by a muscle (the opposite of GRF)

Question 29

define kinematics and their unit

Answer 29

joint angles (degrees)

Question 30

define kinetics and their unit

Answer 30

joint moments (N*m/kg)

Question 31

can there be differences in joint moments when no differences are seen in gait kinematics?

Answer 31

yes

Question 32

what is the center of mass in humans and where is it

Answer 32

slightly in front of S2, center of mass is the “balance point”

Question 33

what is the center of gravity

Answer 33

the point at which the effects of gravity are completely balanced

Question 34

rotating around the center of mass in humans is also known as what?

Answer 34

a fall

Question 35

what point of the gait cycle is potential energy the greatest?

Answer 35

swing phase specifically feet adjacent

Question 36

what point of the gait cycle is kinetic energy the greatest?

Answer 36

lowest point, IC or OIC