MHC Ergonomics & Human Factors 1 — Questions and Answers
Question 1: What is the maximum recommended single-lift weight for an average adult male worker according to NIOSH guidelines?
- 25 lbs
- 51 lbs (Correct answer)
- 75 lbs
- 100 lbs
Correct answer: 51 lbs
NIOSH sets 51 lbs (23 kg) as the recommended weight limit under ideal lifting conditions for an average adult male.
Question 2: Which of the following best describes a 'neutral posture' in material handling ergonomics?
- Bending at the waist to reach a load
- Keeping joints in their natural, mid-range position (Correct answer)
- Extending arms fully overhead to stack items
- Twisting the torso while carrying a load
Correct answer: Keeping joints in their natural, mid-range position
Neutral posture means maintaining joints near their natural mid-range positions, minimizing stress on muscles and tendons.
Question 3: Which type of musculoskeletal disorder (MSD) is most commonly associated with repetitive heavy lifting in warehouse environments?
- Carpal tunnel syndrome
- Lower back injury (Correct answer)
- Rotator cuff tear
- Tennis elbow
Correct answer: Lower back injury
Lower back injuries are the most prevalent MSD in material handling due to the compressive and shear forces placed on lumbar discs during lifting.
Question 4: When performing a team lift, which action is most important to coordinate before moving the load?
- Deciding who will carry the most weight
- Establishing a verbal signal to lift and move simultaneously (Correct answer)
- Selecting the fastest worker to lead
- Wearing matching personal protective equipment
Correct answer: Establishing a verbal signal to lift and move simultaneously
A shared verbal signal ensures all workers lift and move at the same moment, preventing uneven loading and loss of balance.
Question 5: Which ergonomic control measure is considered the most effective for reducing manual material handling hazards?
- Providing back belts to workers
- Implementing engineering controls to eliminate the hazard (Correct answer)
- Rotating workers between heavy tasks
- Training workers on proper lifting technique
Correct answer: Implementing engineering controls to eliminate the hazard
Engineering controls—such as conveyors, lift assists, and adjustable workstations—eliminate or reduce the hazard at the source, making them the most effective control.
Question 6: What does the NIOSH Lifting Equation's Recommended Weight Limit (RWL) help determine?
- The maximum speed at which a load can be transported by conveyor
- The safe load weight for a specific lifting task and conditions (Correct answer)
- The load capacity of a forklift under ideal conditions
- The minimum number of workers required for a team lift
Correct answer: The safe load weight for a specific lifting task and conditions
The RWL defines the weight below which most healthy workers can perform a specific lift without undue risk of lower-back injury.
Question 7: Which factor does NOT directly affect the NIOSH Recommended Weight Limit (RWL) calculation?
- Horizontal distance of the load from the body
- Vertical height of the lift
- Worker's age and seniority (Correct answer)
- Frequency of lifting per minute
Correct answer: Worker's age and seniority
The NIOSH equation uses task-specific multipliers (horizontal, vertical, distance, asymmetry, frequency, coupling) and does not factor in a worker's age or seniority.
MHC Ergonomics & Human Factors 1
What is the maximum recommended single-lift weight for an average adult male worker according to NIOSH guidelines?