Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physical Ergonomics > Module 3. Workload > Flashcards

Module 3. Workload Flashcards

1
Q

Estimates the extent of physical activity

A

Energy Expenditure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

All energy in the body utilized during physical activity produces ___

A

Heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Strenuous activity means ___ energy requirement

A

Greater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

5 ways to measure/estimate energy expenditure

A
  1. Direct Calorimetry
  2. Indirect Calorimetry - O2 Analysis
    3.Indirect Calorimetry - CO2 Analysis
  3. Calculations of Energy Expenditures
  4. Heart-rate Measurement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q
  • Body heat output as a measure of energy expenditure
  • Body heat output is measured under laboratory conditions
  • Can be impractical due to the required setup
A

Direct Calorimetry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q
  • Measurement of oxygen uptake
  • Requires information on volume of expired air
  • Analysis of oxygen content in expired air
  • Air volume determined through a spirometer
  • Estimation of energy based on equation by -J. B. Wier
A

Indirect Calorimetry – O2 Analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Formula for Indirect Calorimetry - O2 Analysis

A

Energy = (Vstp [Oi - Oe])/20
Where
Energy is in kcal/min
Vstp = volume of air expired in L/min
Oi and Oe = Percentages of oxygen in inspired and expired air, respectively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Gas analysis of carbon dioxide content in expired air
* Most methods use infrared properties of carbon dioxide with an instrument, capnograph

A

Indirect Calorimetry – CO2 Analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Two things to take note for this calculation:
* Accurate account of all activities and time spent for each in a day
* Metabolic cost of each activity

What type of method in estimating energy expenditure?

A

Calculation of Energy Expenditures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Formula for Total Energy Expenditure

A

Total Energy Expenditure = E time spent per activity (min) x metabolic cost per activity (kcal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are activities recorded in calculating energy expenditures

A

Detailed questionnaire – might be unreliable (dependent on memory; may exaggerate)
* Diary techniques – subject records daily activities in a diary (minute by minute or 5-minute periods); an observer may be employed to log activities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Indirect measurement of energy expenditure
* ___ and energy expenditure are related
* - May greatly vary based on activities (e.g., lifting a sack of rice vs lifting piece of paper)
* - May also vary based on muscle groups used (e.g., walking vs lifting weights)
* - Can also be affected by physical fitness (e.g., athletes expend more energy)
* - Emotion, body temperature, type of drinks can also affect ___
* Range of variation among population is large
* - Solution is to group/subdivide people

A

Heart-rate Measurement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Heart-Rate Measurement Formulas

A

Male = -55.0969 + (0.6309HR) + (0.1998Weight) + (0.2017*Age) / 4.184

Female = -20.4022 + (0.4472HR) - (0.1236Weight) + (0.074*Age) / 4.184

HR in bpm; Weight in lbs; Age in years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Normal Resting Heart rate of a healthy adult is between ___ to ___ bpm

A

60 - 100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Healthy athletes have even lower normal resting heart rate – can go as low as __

A

40

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Heart rate guidelines based on intensity of activity

A

Moderate intensity physical activity = 64% - 76% of Max HR

Vigorous intensity physical activity = 77% - 93% of Max HR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Estimation of Max Heart Rate

A

220 - age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
  • A scale used to know perceived intensity of an activity, such as exercise or physical/manual labor
  • Developed by Gunnar ___ for rating exertion and breathlessness during physical activity
    • Reflects how hard the activity is through heart rate and respiration, perspiration and muscle exertion
A

Borg Rating of Perceived Exertion (RPE)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Original Borg RPE has a scale of __ to ___

A

6 to 20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Later revised to ____ or ____, has a scale of __ to ___

A

Category Ratio Scale (CR10 Scale)
Modified Borg Dyspnoea Scale
0-10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Method of Use of Borg RPE

A
  • Participants are asked to rate their exertion of activity based on the scale
  • Taking into consideration feelings of physical stress or fatigue
  • Focusing only feeling of exertion, not on the pain experienced
  • Number in scale connotes intensity of activity; tells us if participant should speed up or slow down movements/activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Occupational and non-occupational risk factors can lead to ___ and ___

A

musculoskeletal disorder (MSD)
work-related musculoskeletal
disorder (WMSD)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Factors that can result in the formation of MSD or WMSD

A
  • Local soft tissue fatigue
  • Sufficient blood flow in these soft tissues
  • Sufficient recovery from fatigue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Three factors must be considered to evaluate work or tasks

A
  1. Force / Forceful exertion
  2. High task repetition
  3. Sustained awkward posture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Higher force requirement = ___

A

Higher Risk and higher muscle effort and higher muscle fatigue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Control Methods for forceful exertion

A
  • Engineering controls – mechanical assists, adjustable height lift tables and workstations, powered tools, ergonomic tools
  • Work practice controls – carts and dollies to reduce lifting/carrying, sliding objects instead of lifting/carrying, eliminating reaching obstruction
27
Q

Higher task repition = ___

A

Higher Risk

28
Q

General cycle time that makes tasks repetitive

A

≤ 30 seconds = repetitive

29
Q

Control Methods for High Task Repetition

A
  • Engineering controls – goes hand-in-hand with improvements in other factors
  • Work practice controls – proper work technique to minimize MSD risk
  • Job rotation – to reduce duration, frequency and severity of MSD risk
  • Counteractive stretch breaks – for recovery from fatigue
30
Q

High Awkward posture =

A

higher force on joints; overload muscles and tendons

31
Q

Joints most efficient when operating closest to ___

A

mid-range of motion of the joint

32
Q

Repetitive and Outside mid-range of motion = ___

A

higher MSD risk

33
Q

Control Methods for Sustained Awkward posture

A

Engineering controls – modify workplace to reduce awkward posture
* Work practice controls – proper techniques in doing a task; work procedures following proper posture should be implemented
* Job rotation and job enlargement – increasing variety of work reduces repeated or sustained awkward postures
* Counteractive stretch breaks – rests and stretching to allow recovery from fatigue

34
Q

What is awkward posture?

A
  • Body position is non-neutral
  • Extreme ends of range of motion
  • Joints eventually become weaker; muscles out of balance
  • Tasks become even more physically demanding; adds unnecessary stress to the body
35
Q

Where is the power zone?

A
  • Close to the body
  • Between mid-thigh and mid-chest height
  • Arms and back can lift the most with least amount of effort
  • Lifting outside power zone → risks and injuries ↑
36
Q

Occurs if tools and materials are placed outside the “Power Zone”

A

Awkward Posture

37
Q

2 different methods in evaluating posture in the workplace

A
  1. Rapid Upper Limb Assessment (RULA)
  2. Rapid Entire Body Assessment (REBA)
38
Q
  • developed in England in 1993
  • Only in 1998 it was first applied
  • Tool focuses only on posture
  • Using the tool can help predict risk of upper extremity MSD
  • Hand
  • Wrist
  • Elbow
  • Shoulder
  • Back

The tool uses a scoresheet to derive a ___ “score”
A composite score is calculated based on individual components in the tool

A

Rapid Upper Limb Assessment (RULA)

39
Q

RULA is mostly applicable in ergonomic assessment of ___

A

seated tasks, high repetition tasks or continual such as
- office workers in the workstation
- Assembly workers in an assembly line

40
Q

predicts the risk of developing MSD or WMSD but for entire body (which includes lower limbs)

A

Rapid Entire Body Assessment (REBA)

41
Q

REBA evaluates

A
  • Required or selected body postures
  • Forceful exertion
  • Type of movement, action, repetition, and coupling
42
Q

the institution that provided the lifting equation guidelines for evaluating two-handed manual lifting tasks

A

National Institute of Occupational Safety and Health

43
Q
  • is the weight of the load that nearly all healthy workers can lift over a substantial period (e.g., 8-hour work shift)
  • recommendation for preventing an increased risk of developing lower
    back pain
A

Recommended Weight Limit

44
Q

Maximum weight to be lifted under ideal conditions is ___

A

23 kg

45
Q

RWL considers six factors for lifting weight to reduce the maximum of 23 kg

A
  • A load of 51 lbs / 23 kg
  • Lifted in the sagittal plane
  • The load is at a height of 75 cm above the floor
  • The load is held 25 cm in front of the body
  • The load is to be lifted no more than 25 cm vertically
  • There is good coupling of the load
46
Q

Six coefficients to reduce RWL to account for task factors
Determined using biomechanical models of spinal loading

A

H = horizontal distance of hands from midpoint between ankles in cm
V = vertical height of the hands from the ground in cm
D = vertical distance of lifting vertically (where the load is being lifted to) in cm
F = frequency or time between lifts, in mins or secs
A = angle of asymmetry of the load in relation to the body, in degrees
C = hand-to-load coupling (quality of grasp based on type of handle)

47
Q

RWL equation

A

LC x HM x VM x DM x AM x FM x CM

Where
LC = load constant
HM = horizontal multiplier
VM = vertical multiplier
DM = distance multiplier
AM = asymmetric multiplier
FM = frequency multiplier
CM = coupling multiplier

48
Q

Load Constant

A

23 kg

49
Q

Horizontal Multiplier

A

25/H cm

50
Q

Vertical Multiplier

A

1 - 0.003 |V-75| cm

51
Q

Distance Multiplier

A

0.82 + (4.5/D) cm

52
Q

Asymmetric Multiplier

A

1 - 0.0032A degrees

53
Q

Frequency Multiplier and Coupling Multiplier

A

refer to tables, FM - lifts/min

54
Q

Answers the question, “Is the weight too heavy for the task?”

A

Recommended Weight Limit (RWL)

55
Q

Answers the question, “How significant is the risk?”

A

Lifting Index (LI)

56
Q

Lifting Index based on results of the RWL equation

A

Lifting Index = Actual Load/ RWL
where actual load is in kg

57
Q

If LI < 1.0

A

the task does not increase the risk of injury

58
Q
  • If LI ≥ 1.0
A

some workers are at risk of injury

59
Q

If LI > 3.0

A

many/most workers are at high risk of injury, leading to low back pain and injury

60
Q

Higher Lifting Index = ___

A

Higher risk of injury

61
Q

If RWL < Actual Weight of load, determine which factor(s) contributes the highest risk, then modify lift

A

Lowes multiplier values = factors of highest risk

62
Q

The lifting (or lowering) equation and LI can only be used when

A
  1. Task/work involves two-handed lifting
  2. Worker is in comfortable lifting posture
  3. The environment is comfortable enough for lifting, including the floorings
63
Q

Limitations of the LI Formula

A
  1. Only one hand is used
  2. > 8 hours
  3. When seated or kneeling
  4. In a restricted workspace
  5. Unstable objects (e.g., buckets, liquid containers)
  6. Involving pushing or pulling
  7. Using wheelbarrows or shovels
  8. Objects of extreme temperature
  9. Poor footing/foot coupling (may cause risk or fall)

Physical Ergonomics (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions