HFS201 SU4 Main PDF

HFS201 Study Unit 4: Work Related Musculoskeletal Disorder ANGELA TAN, PH.D HEAD OF PROGRAMME, HUMAN FACTORS IN SAFETY RESEARCH LEAD, BEHAVIOURAL INSIGHTS CENTRE OF EXCELLENCE SAFETY MOMENT Course Schedule Venue: LTB.5.04 16 Aug (Fri) 7.00pm: Study Unit 1 – Anthropometry in workspace design 31 Au...

HFS201 Study Unit 4: Work Related Musculoskeletal Disorder ANGELA TAN, PH.D HEAD OF PROGRAMME, HUMAN FACTORS IN SAFETY RESEARCH LEAD, BEHAVIOURAL INSIGHTS CENTRE OF EXCELLENCE SAFETY MOMENT Course Schedule Venue: LTB.5.04 16 Aug (Fri) 7.00pm: Study Unit 1 – Anthropometry in workspace design 31 Aug (Sat) 8.00am: Study Unit 2 – Workspace design principles 13 Sep (Fri) 7.00pm: Study Unit 3 – Manual material handling GBA due – 19 Sep 27 Sep (Fri) 7.00pm: Study Unit 4 – Musculoskeletal disorders Quiz due – 27 Sep to 3 Oct 11 Oct (Fri) 7.00pm: Study Unit 5 – Office ergonomics (run through GBA) 25 Oct (Fri) 7.00pm: Study Unit 6 – Designing for special populations (Class Revision) Written examination - 15 Nov 4pm – 6pm Learning Outcomes Study Unit 3: Manual Material Handling List the regulations and standards available to manage manual handling work Demonstrate appropriate solutions to mitigate risk through redesign of the task, workspace, and work practices Study Unit 4: Work-Related Musculoskeletal Disorders (WRMSDs) Describe the characteristics of musculoskeletal disorders in the workplace Recognise the signs and symptoms of musculoskeletal disorders affecting the body Understand the risk factors that contribute to the development of work-related musculoskeletal disorders Explain the different types of common musculoskeletal disorders occurring in the workplace Evaluate workplaces for the risk of musculoskeletal disorders through the appropriate use of methods and tools Provide suitable ergonomics interventions and recommendations to control the risk of work-related musculoskeletal disorders  How Our Eyes Work Cones are responsible for color perception. Cones play a role in the initial stages of dark adaptation. Rods responsible for night vision. The pupil dilates to increase the light entering in dark places and vice versa in brightly lit environments. Adaptation from dark to light occurs in a few minutes; Adaptation from light to dark can take up to 30 RECAP minutes Sudden changes in luminance can cause temporary blindness, increasing accident risk. The Normal Line of Sight is the preferred direction of gaze when the eyes are at rest. This is about 10 to 15 degrees below the horizontal plane. Items that require close viewing should be placed in front of the worker at a reading distance of 40 cm to 80 cm away (Kroemer et al., 2001). (Source: https://www.epd.gov.hk/eia/register/report/eiareport/ eia_1242006/html/EIA_Report/Section_6.htm)  Which would you buy? RECAP  Glare Direct glare which travels straight from the light source and Indirect glare which is reflected from a surface into the eyes. To reduce glare, Place high intensity light sources outside the visual field For task lighting, the line of sight from the eye to the lamp should have an RECAP angle greater than 30 degrees Replace one high-intensity light source with multiple low-intensity light sources away from the line of sight Use indirect lighting. This reduce shadows and produce an even illuminance Fluorescent lamps fixed to the ceiling in rows should be arranged parallel to the line of sight  Occupational hazards are conditions in the workplace that pose risks to employee health and safety. Ergonomic Hazards: Strains from repetitive motions, improper load and lifting, awkward postures, long sustained positions. Chemical Hazards: Exposure to harmful substances like solvents, pesticides, and cleaning agents. Biological Hazards: Risks from exposure to viruses, bacteria, and other RECAP pathogens, especially in healthcare settings. Physical Hazards: Environmental factors such as radiation, extreme temperatures, and noise. Psychosocial Hazards: Fatigue, stress, harassment, and violence in the workplace. These hazards can lead to fatalities, injuries, illnesses, low productivity and attrition.  The Human Skeleton as a system of levers Muscles that move limb bones are attached near joints. High moment is balanced by erector muscles and causes high stress at L5/1. These muscles contract a small distance, like a lever, to move the other end of the bone. This movement is passed to the next bone, further increasing the motion, forming a multilever effect. RECAP Human tissue is designed to withstand force. Tissue injury happens when: Amount of force on the body is too big Duration of exposure is too long (overuse injury) If the task demand exceeds the individual’s capability, there is a risk of injury. Risk of Injury when Force Exceeding Tissue (Chaffin & Andersson (1991) Fig 6-34) Tolerance is Applied.  MMH Risk Factors Force of Load RECAP Posture while handling load Frequency of manipulating load Duration of task and shift Environment in which task is carried out  Ergonomics Principles Reduce the distance from the load to the trunk Increased Stress when Lifting Load Further Away from Centre of Mass. Ergonomic Approaches to Identify & Quantify Risks Techniques that are easy to administer makes many assumptions: RECAP NIOSH Lifting Equation REBA and RULA Always check the assumptions while using. They are good for pre-post measurement to (Source:https://neckandback.com/treatments/conser illustrate the improvement of an ergonomic vative- treatment-of-mechanical-lower-back- intervention to management. disorders/) Techniques that can diagnose MMH uses IMUs and video analytics to quantify MMH risks. They require deeper analysis taught in HFS206. Overhead tasks Approaches to Control MMH Risks As with all other risks, we can apply what we learnt in SU1 and SU2: Redesigning the workplace Redesigning the load Redesigning the job Let’s compare these approaches with the Hierarchy of Control. Hierarchy of Control Widely recognized as a fundamental concept in workplace safety management. The specific visual representation as an inverted pyramid or triangle became popular over time, though different organizations may depict it slightly differently. It prioritizes the most effective methods of risk mitigation down to personal protective equipment as a last resort. Earliest formal presentations of the idea was in 1950 by the National Safety Council (NSC). Became more widely adopted after the creation of OSHA (Occupational Safety and Health Administration) and NIOSH (National Institute for Occupational Safety and Health) in the 1970s. Hierarchy of Controls (Hot Stove) Think of it like dealing with a hot stove: The best option is to turn it off (eliminate), If you can’t, use a microwave instead (substitute), If you can’t, put a barrier around it (engineering control), If you still can’t, teach people to be careful (administrative control), or Wear oven mitts (PPE). Hierarchy of Controls Get rid of it: If something is dangerous, the best thing to do is to completely remove it. Replace it: If you can’t get rid of it, try to use something safer instead. An example would be to automate the system so that the worker does not need to lift the load and is no longer exposed to the risks. Keep it away: Use tools or equipment to keep people away from the danger. Change how you do things: Adjust the way people work to make it safer, like giving them training or changing their work hours. Wear safety gear: If nothing else works, use protective gear like gloves, masks, or goggles. Redesign the Job Elimination. Can the liquid be transferred through pipes eliminating the need for human to lift the pail? Substitution. Can the twisting action be substituted with a robotic arm? Engineering Control. Can the workplace introduce a lifting tool? Can the pail be redesigned to include handles that facilitate the lifting? Administration Control. Can you teach workers proper lifting techniques? PPE. Can a back support belt be provided? Would providing anti-slip gloves help? Examples of Engineering Controls Common lifting tools: Forklifts Lifting hoists Lifting jacks Pallet trucks Winches Cranes Chain Blocks Downloaded from https://lifting365.com/blogs/blog/types-of-lifting-equipment-guide- to-lifting-gear  ENGINEERING CONTROL: REDESIGN THE WORKSPACE Work equipment, tools, and surfaces required to complete the job should be provided at the workplace to assist the material handler in doing the task. If there is no surface available to place the load, then people will be forced to place it on the floor which require bending to lift. Engineering Control: Redesign the Load A solution to reducing the risk imposed on the worker is to redesign the load. Here are some guidelines to follow when designing the load: Load size should not be wider than shoulders for one person carry Abnormal shapes and uneven weight make loads difficult to handle Loads should be of proper form and shape such that a good hand grip is possible Add handles and improve grip to increase coupling Allow for a power grip not pinched fingers Handles should ensure hand and forearm postures are aligned and not bent Examples of Administrative Controls Implement job rotation. Manual handing tasks are alternated with light work such as computer work. Reduce the pace of the work. This is important when work is not self-paced such as working on an assembly line. This helps reduce the frequency of handling loads. Increase rest breaks. This allows the body to recuperate and reduces the frequency and duration of handling loads. Reduce repetitive motions. This can be done through task variation, where workers are given more than one task to switch between. Training workers lifting techniques. Loads should not be handled below the knee or above the shoulders Personnel Selection. Select people who are fit for the task. Personnel Training (conditioning) What can be included in the training? Training proper lifting techniques. Include practice to improve skills and muscle memory. Making the body physically fit so that it is less susceptible to injury. Teach the biomechanics. Get employee to be aware of, and take ownership of back injuries and their health Get the load close to the body Do not twist the back or bend sideways Do not continue lifting/carrying when the load is too heavy Personnel Selection The personal characteristics of the worker should be considered when evaluating risk of manual handling. Age. Muscular strength starts declining in older workers and whether the Experience in lifting loads in previous jobs as this helps with conditioning and therefore reducing injury. Workers should be screened through medical (physical) examination before being assigned to manual handling work. This screening may include the following (Kroemer et al., 2003): Physiological examination Targeted biomechanical examination to assess musculoskeletal strength Psychophysical examination Static tests to assess isometric strength Dynamic strength tests  PERSONNEL SELECTION A battery of tests which simulate the task required can be developed to test the individual before hiring. Source: https://www.army.mod.uk/physical-employment-standards/ Watch: The Load Effects Assessment Program (LEAP) (youtube.com) Personal Protective Gears Key Considerations Match PPE to specific hazards Ensure proper fit and comfort Follow regulatory requirements Provide training on correct use Downloaded from https://mnltap.umn.edu/guides/ppe Exoskeleton PPE New lifting tools? New hazard? Let’s meet back at 8.10pm What is work related musculoskeletal disorders (WRMSD)? It is MSD caused by work-related activities. MSD can be caused by sports, leisure, or domestic activities. Inflammatory and degenerative injury which affects the muscles, tendons, ligaments, joints, nerves and blood vessels Characteristics of WRMSDs WRMSD is also known as Repetitive Strain Injury (RSI) and Cumulative Trauma Disorder (CTD) 1. Overuse injury - Develop when the same muscles are used over and over without enough rest 2. Progressive in nature Symptoms Pain Swelling and tenderness Limited range of motion or feelings of stiffness Tingling, numbness How do WRMSDs develop? Arise from a range of daily life activities Work and outside of work Caused by interplay of multiple variables such as health, age, work organization and social aspects HF and WSH specialists should not aim to diagnose but to consider reporting symptoms during workplace evaluation Prevalence of WRMSD Britain vs Singapore (above) Work-Related Musculoskeletal Disorders statistics in Great Britain, 2021 (right) Ministry of Manpower Singapore. (2023). Workplace Safety and Health National Statistics 2023. Retrieved from https://www.mom.gov.sg/-/media/mom/documents/safety- health/reports-stats/wsh-national-statistics/wsh-national- stats-2023.pdf Tendinitis and other forms of injuries Tendinitis Muscles Strains and tears - swelling and pain Inflammation of the Tendons. Tendons Strong and inelastic - can tear Scar tissue – inflammation Tendons connect muscles to the bone. Ligaments More often related to single trauma Tendonitis can be caused by overuse, repetitive Repetitive motions - lead to sprain and joint instability motions, or injury. Tendonitis commonly affects shoulders, elbows, Nerves Pressure from tissues within the body or from hard surfaces = nerve compression wrists, knees, and Achilles tendon Nerve impairment = numbness, tingling and pain Blood vessels Compression reduces blood flow (oxygen supply) – fatigue quicker Overhead Task Flexed and abducted upper arms at the shoulder with hands above shoulder level Neck extensors to counteract weight of tilted head Strongly associated with shoulder injuries and pain. Can also impact neck and back Thoracic Outlet Syndrome An impingement of the neurovascular bundle at the thoracic outlet Symptoms Pain or weakness in the shoulder and arm, tingling in fingers, arm fatigue, and sometimes atrophy of hand muscles Risk Factors Repetitive overhead arm movements Over-exertion at the shoulders Traumatic injuries (e.g., car accidents) Rotator Cuff Tendonitis Inflammation of the tendons in the rotator cuff Symptoms Pain and swelling in the front of the shoulder and side of arm Pain triggered by raising or lowering arm Risk Factors Repetitive overhead motions, especially in sports like swimming, tennis, and baseball Occupations requiring frequent overhead work Age-related degeneration of tendons Poor posture or shoulder mechanics Direct trauma to the shoulder Neck Tension Syndrome An irritation of group of muscles in the neck Risk Factors Symptoms Poor posture, especially from prolonged computer/phone use pain and tightness in the neck, shoulders and upper back Stress and anxiety Sleeping in awkward positions Repetitive neck movements Teeth grinding (bruxism) Lower Back Problems Can be muscle strain, sprain, Disc herniation, joint injury, nerve impingement, inflammation, muscle guarding. Causes Poor posture - flexion of spine Handling heavy loads Risk Factors Numbness & pain in the lower-back, lower limbs Spondylosis Risk Factors associated with MSDs Awkward Posture. Deviation from neutral postures e.g. pipetting or sewing industry; arm elevation above 60° Sustained positions increase risk especially overhead Repetitions worsen with rapid work pace High force / shock / heavy lifting and forceful manual exertions Long duration with insufficient recovery time Exposure to vibration or mechanical compression Increased risk of injury when worker exposed to more than one factor. Any of these in combination with each other or with undesirable features of the psychosocial work environment such as high demands and low degree of control over one’s own work increases risk Carpal Tunnel Syndrome Compression of median nerve in carpal tunnel of wrist Symptoms Numbness/tingling in thumb, index, middle fingers Hand/wrist pain, especially at night Weakness in thumb Risk Factors Repetitive hand/wrist motions Conditions like arthritis, diabetes, pregnancy Vibration white finger Condition caused by regular and frequent use of vibrating hand-held tools or machinery. Also known as Hand-arm Vibration Syndrome (HAVS) Symptoms Numbness and tingling in fingers Loss of sensation and dexterity in hands Fingers turning white (blanching), especially in cold conditions Risk Factors Prolonged exposure to vibrating tools like power drills, chainsaws, sanders, grinders, etc. Trigger Finger Condition where a finger or thumb catches or locks when bent Symptoms Pain and stiffness at the base of the affected finger A catching or popping sensation when moving the finger Finger getting stuck in a bent position Risk Factors Repetitive gripping motions Certain medical conditions like diabetes, rheumatoid arthritis, gout  Tennis Elbow (Lateral Epicondylitis) Pain on the outside of the elbow. Symptoms Pain and tenderness on the outside of the elbow Pain that may radiate into the forearm and wrist Weak grip strength Pain when lifting objects, making a fist, or extending the wrist Risk Factors Overuse and repetitive motions of the forearm muscles and tendons Racquet sports, painting, plumbing, typing, or using hand tools Cubital Tunnel Syndrome Compression of ulnar nerve at elbow Symptoms Numbness/tingling in ring and little fingers Elbow pain Hand weakness Risk Factors Repetitive elbow flexion Direct pressure on elbow Elbow trauma/arthritis  COMMON BUT DIFFICULT TO QUANTIFY Difficult to obtain accurate data on the incidence and prevalence High-risk sectors include nursing facilities, air transportation, mining, food processing and heavy and light manufacturing Surveys of working populations have reported upper extremity symptom prevalence's of 20 to 30% or even higher. METHODS TO IDENTIFY WRMSDS QUESTIONNAIRE INTERVIEWS OBSERVATIONS DIRECT Questionnaires Visual Analogue Scales Location, type and level of pain BORG scale Measured perceived exertion Moore and Garg Strain Index Quantify risk factors associated with developing MSD in hand intensive high repetition task Cornell MSK Questionnaire Nordic MSK Questionnaire Cornell Musculoskeletal Discomfort Cornell Musculoskeletal Discomfort Questionnaire Hand Nordic Musculoskeletal Questionnaire Methods to gather MSK data Examine Standard Operating Procedures Understand cycle times and exposure Employee Interviews Used to gather more information about the discomfort as well as uncover possible causes by asking questions relating to the individual’s job Identify fatiguing and difficult tasks Structured, unstructured or semi-structured formats Questionnaires can also be used in the interview to gather data about the stage and severity of the reported discomfort Methods to gather MSK data Observation Used to understand task demands and exposure to risk factors awkward postures, repetitive tasks, high force application, and poor workspace design E.g. REBA and RULA tool, NIOSH lifting equation Can reveal issues that are not self-reported through interviews or questionnaires Used to determine if the job is posing the risk or other factors outside of work Direct Measurements Force measurement EMG Sensors Computer modelling software Class Activity (20 min – ends 9.10pm) Read the following case study which looks at the prevalence of and risk factors associated with WRMSDs in nurses in nursing homes. “Self-Reported Musculoskeletal Disorder Symptoms among Bus Drivers in the Taipei Metropolitan Area” Answer the following questions: 1. List the methods or tools used to gather data on the WRMSDs 2. What was the most prevalent injury amongst the Bus Drivers? 3. How would you improve this study? Upload your answers in CANVAS. Prevention of MSK Redesign to neutral position Provide support / assistive technology Provide fixtures to hold the load Design for movement Limit exposure time Give regular breaks Stretching exercises PPE (e.g. anti-vibration glove)  PREVENTION OF NECK PAIN Avoid head and neck flexed more than 15 degrees Avoid static head postures Greater risk of pain if neck rotated and shoulders elevated Use a sloping desk angle (10 degree) to reduce the cervical load of 15- 22% Prevention of shoulder pain Eliminate elevated shoulder positions Work with elbows close to body Prevent frequent reaching forwards or outwards If work is above shoulder level, reduce the load and time required to hold a static posture Provide arm supports Provide fixtures to hold work object Prevention of hand/wrist pain Tools should be designed to encourage neutral wrist posture Grip strength depends largely on wrist posture Bend the handle, not the wrist Redesign equipment to reduce or dampen vibration Provide gloves Prevention of hand/wrist pain Improve tool design Consider the weight of the tool Optimize dimensions of tools in relation to hand anthropometry There should be enough hand-to-handle contact Avoid pinch grip Handles with high friction surfaces to improve coupling to maintain grip RTW Program MOM launched The RTW Programme in November 2017. RTW supports the employer and employee by: Providing regular updates to employers Working together to craft a plan to safely transit the worker back to work Medical assessments More information on the RTW can be found under Programme in the WSH Council webpage. Singapore Standard SS 569: 2011 Code of Practice for Manual Handling Legally, workplaces in Singapore are expected to meet SS569 as a minimum. Includes the identification and risk assessment of manual handling hazards and appropriate risk control measures Provides guidance on planning and implementation of an ergonomics programme for manual handling operations. Provides a risk assessment checklist and the latest practices in helping workers avoid injuries due to manual handling This standard is accessible via the Multimedia Stations at all NLB libraries, including the public libraries and Lee Kong Chian Reference Library, except for library@orchard and library@chinatown. ISO 11228 Ergonomics Manual Handling Covers lifting and carrying, pushing and pulling, and handling of low loads at high frequency. Specifies recommended limits for manual lifting and carrying with consideration for intensity, frequency, and duration of the task. Provides guidance on the assessment of several task variables, allowing the health risks for the working population to be evaluated. Applicable to manual handling of objects with a mass of 3 kg or more based on an 8-hour working day Limitation: does not account for combined tasks SUMMARY Hierarchy of Control as a method to generate solutions Work Related Musculoskeletal Disorder Prevalence Common Types Method to evaluate Challenges in quantifying Prevention of MSK (Hierarchy of Control) Return to Work programme Standards related to MSK Remind each other to complete the quiz. That’s Care - SU1 (Anthropometric Design Principles) 10% of your assessment. Community - SU1 (Seated vs Standing Work) Prepare a 5 min presentation to do a recap of Courageous – SU1 (Anthropometric Calculations) HFS201. You will prepare over the next 2 Creativity – SU1-2 (Anthropometric Scaling - RASH method) student-led sessions. The objective is to: Growth Mindset – SU2 (Task Analysis & Workspace Design Principles) - Revise for the written exam Integrity – SU2 (Design for Vision) - Share with your friends what is important Kindness – SU3 (Manual Material Handling) The presentation will happen on the last lecture. Leadership – SU3 (Hierarchy of Control) It is not graded. Safety First – SU4 (WRMSK) Student Led Session  [email protected] [email protected] Next 11 Oct 2024 (Friday) 7pm Lecture LTB.5.04