Ergonomics

Question 1

You must empower the ____ not the ____.

Answer 1

1. Worker
2. Task

Adapt the workstation to the worker, not the worker to the workstation

Question 2

Ergonomics Focus

Answer 2

• Injury reduction
• Accident reduction
• Improvement in work performance

Gov Agencies: NIOSH nad OSHA

Question 3

______ generally define the needs of the workspace

Answer 3

Anthropometrics

Height, weight, skill level, strength, and age

Question 4

What mechanical factors can we change relative to the performer and/or his/her environment?

Answer 4

Knees and shoulders - “Strike Zone”

Question 5

Common Workplace Injuries

Answer 5

• Head and neck, lumbar spine, shoulder, wrist and hand
• Overuse/work-related injuries

Question 6

Worker Posture - Seated: Advantages

Answer 6

• Less physiological demand
• Less load on the lower extremities
• Greater postural stability
• Visual & motor control
• Less demand on the cardiovascular system

Question 7

Worker Posture - Seated: Disadvantages

Answer 7

• Lumbar spine flexion, spinal ligament tension
• Impaired breathing & digestion
• Pressure distribution?
• Ischial tuberosities, posterior thigh
• Increased lumbar disc compression
• Blood flow in legs

Question 8

Any seated environment =

Answer 8

Increase in interdiscal pressure

Question 9

Area

Answer 9

contact area

Question 10

Pressure

Answer 10

Force/Area

Question 11

How do you get peak pressure?

Answer 11

Single force plate value

Question 12

What does a cushion do?

Answer 12

Provides more contact area with the sheet, force is more dissipated.

Question 13

NIOSH Lifting Equation

Answer 13

• To assist employers in reducing the risk of lifting-related injuries, NIOSH developed a lifting equation designed to determine the safety of lifting tasks
• Data are measured at origin (start)
• and destination (end) of the lift

Question 14

Load Constant

Answer 14

Predetermines value of 51 lbs is considered risky. Should be a team lift.

Question 15

Lifting Index

Answer 15

• Object Weight/RWL
• LI >1 = ergonomic improvements are necessary to reduce the risk of injury

Question 16

Horizontal Location

Answer 16

• Distance of the hands away from the midpoint between the ankles (base of support)
• Closer is easier, moment arm

Question 17

Vertical Location

Answer 17

Distance of the hands above the floor
Best: Knuckle height in standing
Strike zone: Lifting is knuckle height to shoulder

Question 18

Safe lifting techniques

Answer 18

• Maintain the external load close to the body
  – Minimizes external moment arm and force demands of back muscles
• Lift with lumbar spine as close to neutral as possible
  – Strong extensor muscle contractions in lumbar flexion or extension will stress disc and facets, respectively
• Minimize vertical and horizontal multipliers
  – Decreases total work (Force*distance) and facilitates neutral posture
  – Repetitive lifting should be between the height of the knuckles and the shoulder

Question 19

Loading in lumbar extension, discs buldge _____

Answer 19

Anteriorly

Question 20

Loading in lumbar flexion, discs buldge

Answer 20

Posteriorly

Question 21

Explain the position in which you would perform precision, light, heavy work.

Answer 21

Question 22

Lumbar Spine and Lifting

Answer 22

Frequency matters, adjusting the job in different positions can be made to allow for not as much stress to be placed.

Question 23

Smaller moment arm =

Answer 23

easier to hold/less stress

Question 24

Rotation and Spine

Answer 24

Causes more muscle activation and stress on vertebreral discs with rotation. Have people move there feet! Not twist!

Question 25

To increase stability we must

Answer 25

sacrifice compression. Not making muscles contract can result in no muscle activation putting stress on ligaments. We want active support to the spine which which results in disc compression. Safer than no activation and hanging on ligaments.

Question 26

Core Stabilization

Answer 26

• Need to provide stiffening through muscle activation.
• Quadratus Lumborum is the best stabilizer of the spine.

Question 27

Back Belt - Weight Training

Answer 27

• Don’t work to stabilize the spine, rather it increases the abdominal pressure.
• Tight to avoid migration and increase abdominal pressure.
• Counteracts torque; Trunk wants to go forward and belt pushes it back.

Back belts don’t work in ergonomics.

Question 28

Materials Handling Situations

Answer 28

• Unstable load - Drop it, more risk to try to safe it then letting it break.

Question 29

Factors in niosh

Answer 29

Repition, rate, assymetery angle, duration, vertical, horizontal components.

Question 30

Cumulative Trauma Disorders (CTD’s) - Risk Factors

Answer 30

• Vibrating tools
• Grip size (distal phalanges & thumb overlap)
• Lower work surface
  – Wrist hand position, amount of shoulder abduction/flexion (<30 degrees)
• High static (isometric) hand forces

Shoulder tendonitis, tennis elbow (lateral epicondylitis) and carpal tunnel syndrome

Question 31

Which is better? Why?

Answer 31

1: Right; Smaller Moment Arm
2: Left; Smaller Moment Arm, Better Handle
3: Right; Good neutral wrist position

Question 32

What is a Functional Capacity Evaluation?

Answer 32

A FCE is a comprehensive, objective test of a person’s ability to perform work-related tasks.

May have a return to work task.