Work of Gait

Question 1

Smooth progression of gait due to what

Answer 1

concentric and eccentric transferring of power

Question 2

Joint power

Answer 2

joint motion x joint angular velocity

Question 3

negative power

Answer 3

eccentric

Question 4

positive power

Answer 4

concentric

Question 5

Hip extensors generate power in ____ to ____

Answer 5

in early stance to propel and extend hip

Question 6

Hip flexors generate power in ____ to _____

Answer 6

in pre and initial swing to advance the limb forward

Question 7

Knee flexors generate power in ______ to ____

Answer 7

early stance to help extend the hip and propel the body forward

Question 8

The quads generate power in _____ to _____

Answer 8

stance to re-extend the knee after loading response

Question 9

The PF generate power in ____ to ____

Answer 9

in terminal stance and preswing to propel the body forward

Question 10

The hip flexors absorb power through ____ to _____

Answer 10

terminal stance decelerate the extended hip and body’s COM

Question 11

The quads absorb power in ____ to ____

Answer 11

loading response to control knee flexion

Question 12

The hamstrings absorb power in ______ to ____

Answer 12

in swing to decelerate the swinging limb

Question 13

The PF absorb power in ___ to _____

Answer 13

mistance to just prior to end of terminal stance to control the advancement of the tibia over the ankle

Question 14

What sequence is responsible for COM progression smoothly during gait?

Answer 14

power generation and absorption

Question 15

Mechanical energy

Answer 15

capacity to performwork

Question 16

Mechanical work

Answer 16

force x distance through which the force acts

Question 17

Muscles perform what kind of work to move our bodies

Answer 17

internal work as they shorten and lengthen over a distance

Question 18

______ is a major determinant in the mechanical cost of walking

Answer 18

mechanical work (force x distance)

Question 19

When is internal muscle work greatest?

Answer 19

when the COM is moved up and forward. The WAY it is moved up rather than the AMOUNT

Question 20

Explain the internal pendulum

Answer 20

As we walk the bodies COM repeadedly swings over the stance limb. This happens with no additional energy input because energy cannot be created or destroyed

Question 21

Potential energy

Answer 21

energy that is stored

Question 22

kinetic energy

Answer 22

energy the produces work or is released

Question 23

Once the car goes over the top of the hill what do you have?

Answer 23

both KE and PE

Question 24

KE and PE are related to what in the body

Answer 24

the distance of the body’s COM from the earth

Question 25

minimizing mechanical energy expenditure is what?

Answer 25

a dominant characteristic of gait

Question 26

what contributes to the efficiency of gait?

Answer 26

the muscles ability to absorb and generate energy. Metabolic energy

Question 27

Mechanical energy (capacity to do work) dictates what?

Answer 27

the metabolic energy you spend and therefore how we move and our efficiency of gait.

Question 28

Looking at energy expenditure gives us what kind of information on gait performance?

Answer 28

global information: it provides quantifying info on the physiologic penalty due to pathologic gait

Question 29

Walking speed that minimizes the cost of gait (m/s, mph and m/min)

Answer 29

1.3 m/s 3mph 79.8 m/min If you walk faster or slower than this you're increasing the cost of gait

Question 30

the amount of energy input that is convered into useful work is called what and humans can achieve what?

Answer 30

physiologic efficiency 20%

Question 31

Energy that is not converted to meaningful mechanical work appears as what?

Answer 31

heat energy

Question 32

Name the three units of energy we talked about

Answer 32

Cal kcal J

Question 33

Direct calorimetry measures what

Answer 33

physiologic energy expenditure by determining the body's heat and work production Impractical

Question 34

Indirect calorimetry measures the volumes of what two things

Answer 34

O2 consumption and CO2 production

Question 35

the rate of O2 consumption per kg of body weight is what?

Answer 35

metabolic power

Question 36

metabolic power determines what?

Answer 36

intensity of sustained exercise related to the length of time an exercise can be performed

Question 37

what is O2 consumption rate at rest?

Answer 37

2.8 ml/kb/min

Question 38

equation for O2 cost

Answer 38

O2 cost = rate of O2 consumption (metabolic power) / walking speed

Question 39

what two ways can O2 cost be increased by

Answer 39

increased O2 rate consumption Decreased walking speed with normal O2 rate

Question 40

What age of people have the "best" efficiency?

Answer 40

adults

Question 41

ankle fusion and gait efficiency vs. hip and metabolic power/O2 rate

Answer 41

not that different in the ankle. vs hip there is a lot of extra movement and compensation and therefore much higher higher O2 rate of consumption

Question 42

what jt jusion has the greatest negative impact on the energy expenditure during gait? Least? Middle?

Answer 42

hip joint fusion had most impact Ankle had least Knee had greater than ankle but less than hip

Question 43

O2 rate of consumption and prosthetics general idea

Answer 43

the higher the amputation the more O2 rate of consumption

Question 44

What body system has a large bearing on O2 consumption?

Answer 44

CV system. Physically feet people

Question 45

What is normal O2 rate of consumption with walking

Answer 45

12

Question 46

in the study malloy showed us how did limb length afect O2 rate

Answer 46

there was no difference but he said to not take this as a generalization. The point is that both are very different than a normal person.

Question 47

Experiment data: cane for two months before study period. How long did it take for can use to decreased energy expenditure in OA patients?

Answer 47

2 months! It can substantially INCREASE energy expenditure in knee OA patients in the first month of use

Question 48

LE pathology causing altered ______ ______ can profoundly increase ______ _______

Answer 48

LE pathology causing altered MUSCLE FUNCTION can profoundly increase ENERGY EXPENDITURE