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Download What is Ergonomics? - AURA-O
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ERGONOMICS Recognition of Work-Related Musculoskeletal, Nerve Disease What is Ergonomics? • Ergonomics is the science of fitting the job to the worker. • Ergonomics refers to a work environment designed to maximize safety and increase productivity. What is Ergonomics Gone Bad? • When there is a mismatch between the physical requirements of the job and the physical capacity of the worker, workrelated musculoskeletal disorders (MSD) may result. Ergonomic Disease • • • • • Repetitive motion injury Cumulative trauma disorder Musculoskeletal disorder (MSD) Repetitive stress injury Sprains, strains, tears Musculoskeletal Disorders • Injuries or disorders of: – muscles – tendons – ligaments – nerves (compression or entrapment) – spinal discs – joints and cartilage Signs and Symptoms • • • • • • Muscle pain Joint pain Swelling Numbness Restricted motion Low back pain Musculoskeletal Disorders • Upper Extremities • Hands • Arms • Shoulder • Neck • Upper Back • Lower Back • Feet and Legs Benefits of Good Ergonomics • Decreased injury risk • Increased productivity • Decreased mistakes/rework • Decreased lost work days • Decreased turnover • Improved moral Risk Factors for Ergonomic Hazards Repetitive Motion/Cycle • Same repetitive task • Use of same muscle groups • Short cycle (~<2/min) Awkward Posture Twisting Overhead Reach Force • Heavy lifting • Forceful exertions, pulling, pushing, twisting Contact Stress • Using the hand or knee as a “hammer” Vibration • Whole body vibration – e.g.., Crane operators, truck drivers • Segmental vibration – Pneumatic tools, grinders Risk Factors Also Depend On: • Duration of stress • Amount of recovery time • Temperature – Decrease blood flow to muscles (cold) And a Higher Risk Occurs When: • Risk factors are multiple Controlling Ergonomic Hazards Control Hierarchy 1) Engineering controls • Physical changes 2) Administrative controls • • • Employee rotation Change of pace Job enlargement 3) Work practice controls • Utilization of better procedures, posture 4) Personal Protective equipment Manual Material Handling and Back Protection Acute vs. Chronic Stressors • Acute: – Where the injury arises from a single identifiable event - when transient loads exceed internal tolerances. • Chronic: – Where repeated trauma (albeit incapable of injury in isolation), after sufficient duration, reduces internal capacity resulting in eventual injury. – Microtrauma Back Injury • • • • Muscle Ligament Vertebrae Discs Ergonomic Risk Factors for Backs • Awkward posture • Sitting • Static, bent postures • Fatigue/aging • Whole body vibration Ergonomic Risk Factors for Backs • Handling excessive weight/force • Load size • Frequency of lifting • Grip consideration • Poor physical condition Kinds of Back Injuries • Back strains-When weak or tense muscles are stretched beyond their limit • Back sprains-A partial or complete tear of a back ligament • Herniated discs-Resulting when stress, strain or gradual deterioration on a disc causes it to stick out between the vertebrae • Ruptured discs-When the wall of a disc breaks open. Upper Extremities WorkRelated MSDs Effects • • • • Pain Inflammation Swelling Numbness • Decrease in range of motion • Loss of function • Cycle of injury UECTD Risk Factors Awkward Wrist Postures Tendon Disorders • Tendonitis: – Fibers can become inflamed, fray or tear apart, tendons can thicken, become bumpy and irregular and without sufficient recovery time become permanently weakened Tendon Disorders • Epicondylitis • Lateral epicondylitis - tennis elbow (inflammation of tendon fibers outside of elbow) Source: American Society for Surgery of the Hand • Medial epicondylitis or golfers elbow (inside) Tendon Disorders Rotator cuff tendonitis • Repetitive overhead work • Elevated elbows Source:NIH, Medline Plus Tendons • Stenosing Tenosynovitis (progressive restriction of the synovial sheath) • De Quervain’s disease (thumb tendons) Tendons Tenosynovitis (injury of the synovial sheath) • Trigger finger (stenosing tenosynovitis crepitans) • Ganglionic cyst (swelling of the synovial fluid) Source: Cleveland Clinic Nerve Disorders • Injuries or disorders of the median nerve: – Carpal tunnel syndrome (compression of he median nerve as it passes through the carpal tunnel) – Pronator syndrome (compression of median nerve as it passes between the two heads of the pronator teres muscle) Cubital Tunnel Pain/Numbness www.medicalmultimediagroup.com Bursitis • Shoulder Bursitis - Bursa irritated and thickens with overuse Neurovascular Disorders • Thoracic outlet syndrome - Caused by compression of the neurovascular bundle from repetitive activities overhead or with the arm pulled down towards the back Neck Disorders • Tension or ache in the neck (local muscle tightness/spasm) • Numbness in the arms or hands (nerve impingement) Lower Extremities WorkRelated MSDs Knee Disorders • Bursitis of the knee • Chondromalacia: degeneration (softening) of the cartilage on the posterior aspect of the kneecap Lower leg disorders • Shin splints: involve damage to one of two groups of muscles along the shin bone (caused by standing for a long time or repetitive stress to the lower leg) Foot Disorders • Plantar fasciitis (inflammation of the plantar fascia--the tissue that forms the arch of the foot) • Tarsal tunnel syndrome (entrapment of the tibial nerve) Work Tool Design • Reduce forces Work Tool Design • Use power grip Work Tool Design • Use optimal grasp span Work Environmental Concerns (Heat Stress,Energy Expenditure and Vibration) Heat Disorders • Heat stroke • Heat exhaustion • Heat cramp • Heat collapse • Heat rash • Heat fatigue Heat Stress Operations • • • • • Iron and steel foundries Nonferrous foundries Brickfiring and ceramic plants Glass product facilities Rubber product factories Factors Affecting Susceptibility to Heat • Age • Weight • Degree of physical fitness and acclimatization • Metabolism Environmental Factors • • • • Air movement Humidity Conduction Radiant heat exchange Engineering Controls • • • • • Ventilation Air cooling Fans Shielding Insulation Types of Vibration • Whole Body • Hand-Arm (HAVS) Summary • When there is a mismatch between the physical requirements of the job and the physical capacity of the worker, work-related musculoskeletal disorders (MSD) may result. • Risk Factors for ergonomic hazards: – – – – – Repetitive motion cycle Awkward posture Force Contact stress Vibration • Upper extremities work-related MSD’s • Lower extremities work-related MSD’s
