OSHA & REGULATORY FOUNDATIONS
If an employer documents musculoskeletal complaints for months but takes no action, how does the General Duty Clause classify this situation?
A violation for failing to correct a recognized ergonomic hazard.
When a worker twists 45° during a lift, which NIOSH variable reduces the Recommended Weight Limit?
The asymmetry multiplier.
A task shows trunk flexion above 60° and deep knee bending. Which tool accurately scores this posture?
REBA.
Why must designers use the 5th–95th percentile range when creating workstations?
To accommodate almost all workers and prevent anthropometric mismatch.
Why are force, posture, and repetition considered the three primary ergonomic risk factors?
They are the main contributors to musculoskeletal strain.
Why is cognitive ergonomics essential in safety-critical digital systems?
It reduces errors by aligning information with human attention limits.
Why is installing adjustable mounting jigs an appropriate control for overhead work?
It eliminates the need for workers to reach above shoulder height.
Why is task rotation effective for kneeling-intensive work?
It reduces continuous pressure on the knees.
Why are knee pads critical for frequent kneeling tasks?
They reduce direct pressure on the knee joint.
Why is elbow-height workstation design ideal for most tasks?
It keeps shoulders relaxed and wrists in neutral alignment.
Why does OSHA consider ergonomic hazards enforceable even without a specific ergonomic standard?
Because the General Duty Clause requires employers to address any recognized hazard.
Why is the Lifting Index (LI) critical for budgeting ergonomic redesigns?
It quantifies risk and shows when a lift exceeds safe recommended limits.
Why is RULA better than NIOSH for analyzing repeated labeling tasks with awkward wrist postures?
RULA evaluates upper-extremity posture and repetition, not lifting
Why is anthropometry essential in tool and workstation design?
It ensures equipment matches real physical dimensions of users.
In a high-speed but low-force hand-labeling station, which risk factor dominates?
Repetition
What does frequent alarm misses on a complex display indicate?
Cognitive overload.
Why do lift tables significantly reduce back risk in warehouses?
They allow lifting from neutral heights instead of floor level.
Why do scheduled visual breaks help reduce eye and neck strain?
They reset visual focus and reduce static posture.
Why does a stylus with a larger grip reduce wrist discomfort?
It promotes neutral wrist posture and reduces pinch force.
Why does a fixed 44-inch surface height create risk for many workers?
It forces shorter workers into shoulder elevation and taller workers into bending.
A company installs new adjustable workstations but injuries continue. What OSHA-aligned step must follow the installation to ensure compliance?
Train workers on proper adjustment and use of the equipment.
A LI of 2.6 indicates what about the task’s risk level?
It exceeds safe limits and requires engineering change, not just behavioral fixes.
What does a REBA score of 11 tell a manager deciding on budgeting priority?
The task requires immediate engineering changes due to very high risk.
What ergonomic problem results from placing a monitor 6 inches too low?
Cervical flexion leading to neck and upper-back fatigue.
Why does poor coupling increase ergonomic risk?
It forces muscles to work harder to maintain grip.
Why is a 3-second alarm response inappropriate for a visually cluttered control panel?
It does not match realistic human reaction times under cognitive load.
Why is aligning dual monitors important?
Asymmetrical viewing increases neck rotation and strain.
Why is rotating between picking and packing effective for foot fatigue?
It changes physical demands and reduces cumulative strain.
Why are anti-vibration gloves only partially effective?
They reduce but do not eliminate vibration transmitted to the hands.
Why is screen-centering critical in design work?
Misalignment leads to repetitive neck rotation.
Why does OSHA encourage neutral posture in 1910 Subparts D and Z?
To minimize joint stress and prevent long-term MSD development.
Why does lifting from floor height drastically increase ergonomic risk?
It increases trunk flexion, spinal compression, and horizontal reach.
Why is neutral alignment important in evaluating workstation design?
It minimizes joint torque and reduces chronic strain.
Why is designing only to average (50th percentile) measurements dangerous?
It excludes large portions of the workforce.
Why does working above shoulder height increase MSD risk?
It elevates the arms, loading the shoulders and neck.
How does simplifying a layout reduce errors?
decreases search time and lowers mental workloa
Why do anti-vibration handles reduce jackhammer MSD risk?
They decrease exposure to harmful hand-arm vibration.
Why is “stretching only” an ineffective ergonomic solution?
It does not address the source of the hazard.
Why is PPE considered the lowest tier of ergonomic control?
It relies on worker behavior and does not remove the hazard.
Why is placing heavy items above shoulder height unsafe?
It significantly increases force and posture risk factors.
What type of control is job rotation, and why is it used in ergonomics?
An administrative control used to reduce prolonged exposure to a single risk factor.
How does poor coupling affect the Recommended Weight Limit during a lift?
It lowers the RWL because the worker cannot securely grip the object.
What is the biggest danger of prolonged static posture?
Restricted blood flow causes cumulative muscle fatigue.
How do anthropometry and biomechanics intersect in construction?
Worker body size must match tool dimensions to minimize force and leverage demands.
How does fixed workstation height create risk?
It forces workers outside neutral posture if it doesn’t match their body size.
What ergonomic principle is violated when too many alarms compete for attention?
The limits of human information processing capacity.
How do tool balancers reduce overhead strain?
They remove sustained weight load from the worker’s shoulders.
Why do micro-breaks matter in repetitive tasks?
They allow muscle recovery without disrupting productivity.
Why do gloves with textured grips reduce fatigue?
They improve coupling and reduce grip force demands.
Why is installing adjustable-height workbenches recommended in redesign?
It accommodates worker anthropometry and reduces MSD risk.
Why are engineering controls preferred over administrative or PPE controls in ergonomic risk management?
They remove or reduce the hazard at the source rather than relying on behavior.
Why is NIOSH not appropriate for analyzing high-speed, low-force repetitive tasks?
It evaluates forceful lifting tasks, not repetitive motion strain.
Why is heat (e.g., 92°F with humidity) considered an ergonomic hazard?
It impairs performance and increases fatigue, affecting posture and decision-making.
Why are adjustable designs preferred in mixed-gender workplaces?
They accommodate wide anthropometric variability.
Why is over-the-shoulder repetitive motion especially risky?
It places sustained load on small shoulder stabilizer muscles.
Why are consistent visual coding systems critical in control rooms?
They speed decision-making by reducing cognitive confusion.
Why are mechanical loaders important for truck-bed loading tasks?
They eliminate the need for lifting above shoulder height.
Why are employees sometimes resistant to carts, and why must admin controls address behavior?
Habits feel “faster,” so training and accountability are required.
Why is PPE alone insufficient for overhead electrician fatigue?
It cannot reduce the force or overhead posture requirements.
hy do anti-fatigue mats help in fixed standing work?
They reduce lower-body muscle fatigue by improving micro-movements and cushioning.