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The Back and Material Handling Issues. Cervical. Thoracic. Lumbar. The Spinal Column. The Basic Structure. Short Term or acute effects: Sharp Surfaces Dropped Material Struck-by Moving Materials Mechanical Stress Slips and Falls “Simpler” Cause and effect relationship.
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Cervical Thoracic Lumbar The Spinal Column
Short Term or acute effects: Sharp Surfaces Dropped Material Struck-by Moving Materials Mechanical Stress Slips and Falls “Simpler” Cause and effect relationship Epidemiology of Back Injuries
Epidemiology Chronic or Long Term Effects • Back Ache or Pain • Disc Degeneration • Cause and effect not as simple, more difficult to analyze
Return to Work • Out more than 6 months only 50% chance of returning • One year only 25% • Management and Practitioner Training One study showed that claims dropped from 200K to 20K per year by providing modified work and conservative treat
Material Handling • Lifting/Lowering • Pushing/Pulling • Carrying • Weights and Forces • Frequency of Activities • Load Center of Gravity
Job Risk Factors • Weight of the Object • Location (position of load w.r.t. worker) • Frequency of Lifts • Stability of the Load • Hand Coupling • Workplace Geometry Twisting/Stooping • Environmental Factors
Personal Risk Factors • Gender • Age • Anthropometry • Lift technique • Attitude • Strength • Training
Examples of Manual Handling Controls • Avoid extreme range of motion when lifting • Redesign work station/work area to allow freedom of movement • Provide handles on material handling equipment • Provide lift-assist devices and tables • Unit Load Concept
Job Design • Can reduce one-third of compensable LBP • Minimize reach and lift distances • Keep off floor • Work station design • Frequency • Relax time standard • Rotation • Work-Rest allowances
Job Design • Minimize Weight • Mechanical aids • Carton capacity • Balance contents • Convert • Carry to push/pull • Push over pull • Use large wheels
Training • Focus on awareness and avoidance • Get object as close to body as possible • Planning • Use of handling aids • Back Schools • Strength and fitness important
NIOSH Lifting Equation • Objective: Reduce occurrence of lifting-related LBP • 1981 and 1991 equations • 1981 limited to sagittal plane • 1991 includes asymmetry and coupling
Disqualifiers for Use • One handed lifts • More than 8 hours • Seated or kneeling • Restricted work space • Unstable Objects • Carrying, pushing or pulling while lifting • Wheelbarrows or shovels • High speed motion • Unreasonable foot/floor coupling • Unfavorable environment
Definition of Terms • RWL = Recommended weight limit • LC = Load constant • HM = Horizontal multiplier • VM = Vertical multiplier • DM = Distance multiplier • AM = Asymmetric multiplier • FM = Frequency multiplier • CM = Coupling multiplier
1991 Equation RWL = LC x HM x VM x DM x AM x FM x CM
1991 Guide • Compare RWL to Actual Load (L) • If Greater than or equal to 1 problem
Lifting Index L RWL
1991 Multipliers • LC = 51 Pounds • HM = 10/H • VM = 1-.0075 x / V-30/ • DM = .82 + (1.8/D) • AM = 1 – (.0032 x A) • FM go to Table • CM go to Table
NIOSH Workshop Start of Lift End of Lift
WISHA If the job is a hazard • Reduce weight of load • Increase weight of load so that it requires mechanical assist • Reduce the capacity of the container • Etc.
References • Applications guide for the revised NIOSH lifting equation – On CD • Elements of Ergonomic Programs – On CD • Musculoskeletal Disorders and Workplace Factors – On CD • Work Practices Guide for Manual Lifting NIOSH 81-122