Workplace Biomechanics & Lifting Flashcards
List and provide an example for each of the 5 types of stress that can be applied to the body.
Shear stress or strain
- Between femur and tibia
- Disc problems increasing hyperlordosis
Compression forces
- Patellar pain
- Fractures to the vertebrae
- Hip joint
Tension forces
- Ligament avulsion fractures
Bending forces
Torsional forces
In relation to back stress, explain the difference between type A, B and C injuries.
- Type A injury = single event
- Type B injury = sequence of sub max stresses
- Type C injury = continuous low grade stress
What factors are involved in back stress?
- Body weight and mass distribution
- Level of muscular strength/ support/ imbalance
- Intra-abdominal pressure
- To provide rigidity for the back
- Position during load
- The resultant compressive and shear forces acting
- Many of above factors influenced by activity and lifestyle
How is biomechanics linked with ergonomics?
Biomechanical concepts such as kinetic measures (mass, moment of inertia & location) along with segment data (center of rotation, origin and insertion of muscle, angle of pull of tendons & length of muscle) are used to create ergonomic designs
Who is NIOSH and what do they do?
- National Institute for Occupational Safety and Health
- Responsible for conducting research and making recommendations for the prevention of work-related injury and illness.
Reductions in workplace back injuries can be achieved by: a) risk identification; b) risk assessment
& c) risk control. Explain each of these phases
Risk Identification
- Analysis of workplace injury records
- Consultation with employees
- Direct observation (analysis)
Risk Assessment
- Actions and movements
- Workplace and workstation layout
- Working posture and position
- Duration and frequency of manual handling
- Location of loads and distances moved
- Weights and forces
- Work organization (flow, order, etc.)
- Skills and experience
- Age
Risk Control
- Job redesign
- Mechanical handling equipment
- Training
- Other administrative controls
- Safe Manual Handling Checklist
What is a lumbar motion monitor and how might it be used?
Measures static and dynamic trunk postural variables that predict risk of back injury
- Maximum sagittal flexion
- Maximum lateral velocity
- Average twisting velocity
- Load moment
- Lift rate
Explain how Homer Simpson’s posture might predispose him to a lifting injury.
Due to having more belly fat which causes more load onto his lower spine, more load when carrying an object which causes hyperextension of the spine could result in a lower back injury
Assessment of a computer workstation should encompass what?
- The Operator
- Equipment placement / design
- Workstation environment
- Workload and operator breaks
List several important computer workstation features in relation to the operator
Head, neck and trunk
- Head vertical and directly on top of neck, trunk vertical
Arms and hands
- Upper arms vertical, forearms horizontal or slightly above, hands in line or slightly below line of forearms
Legs
- Feet flat on floor or footrest, lower legs vertical, thighs horizontal
List several important computer workstation features in relation to equipment placement/design
Keyboard
- In position to allow correct positioning of arms and hands
Chair
- Waterfall front to prevent sciatic nerve impingement, five supports on base, minimum support for back = lower onethird of lumbar region to maintain lumber lordosis
VDU (monitor) height
- Best colour contrast = yellow on black; turn brightness down as much as possible and contrast up as much as possible; keep VDU at arms length to minimise radiation; VDU in line with eye line to allow 10° - 20° arc of vision
Often used items should be within easy reach
- Arms length
List several important computer workstation features in relation to workstation environment
Reflections
- Lighting standards [look at naturally occurring illuminance on a horizontal surface]
Contrast
- Appropriate contrast between object and visual field
- Ratio of luminance of work are to surroundings can be 3:1 between a task and its immediate surroundings to 10:1 between a task and the wall or floor
Lighting design considerations
- Suitable level of illumination
- May increase glare
- Older workers require higher levels
Balance of surface luminance’s
- 3-D appearance
- Use of different materials
Avoidance of glare
- Reduced by combination of direct or indirect light
List several important computer workstation features in relation to workload and operator breaks
Ensure Posture changes
- To alleviate stress / improve muscle function
Micropauses
- Small pauses - shutting eyes or looking at something in the distance
Breaks
New staff adapting to job
- Start small, have regular breaks
Which style of lifting is best?
Bend your hips and knees to squat down to your load, keep it close to your body, and straighten your legs to lift.
List 3 strategies to prevent an overexertion injury
- Design the task for all workers
- Select workers believed to be at low risk
- Train workers to reduce their personal risk levels
