Presentation on theme: "Workplace Ergonomics: Understanding and Preventing Musculoskeletal Disorders and Injuries Part II: Identifying the Risk Factors for Musculoskeletal Disorders."— Presentation transcript:
Workplace Ergonomics: Understanding and Preventing Musculoskeletal Disorders and Injuries Part II: Identifying the Risk Factors for Musculoskeletal Disorders Developers: Margaret Nuesca and Karen Traicoff (Occupational Therapy Students) Project Advisors: Tiffany Boggis, MBA, OTR/L and Zachery Collins, MOTR/L, CEAS Director, School of Occupational Therapy: John White, Ph. D, OTR/L Spring 2010
Ergonomic Risk Factor Interaction Worker Task/Job Environment The goal of ergonomics is to design the job to fit the worker NOT make the worker fit the job Risk factors inherent in the Worker: - Physical - Psychological - Non-work related activities Risk factors inherent in the Job: - Work procedures - Equipment - Workstation design Risk factors inherent in the environment - Physical - Psychosocial climate
Risk Factors that lead to Musculoskeletal Disorders Repetition Force Posture Duration Contact Stresses Psychosocial factors
Repetition Repetition is performing the same postures or motions again and again –Can be very frequent over short period of time –Can be less frequent but repeated over time A job is considered repetitive if the basic cycle time is less than 30 seconds primarily for hand/wrist motions –Example: Typing on a keyboard A job requiring back or shoulder movements is considered repetitive with a several minute interval –Example: Lifting boxes from the floor Repetition combined with other risk factors such as awkward postures and force can increase the risk injury. Examples: –Typing on a keyboard with wrist bent –Holding a phone with shoulder and cheek –Lifting heavy material without proper body mechanics
Force Defined as a strenuous physical exertion usually with heavy loads, may be performed as a push, pull or lift. Common activities contributing to excessive force: –Lifting and carrying –Pushing and pulling –Reaching to pick up loads –Prolonged holding –Pinching or squeezing Force combined with other risk factors such as awkward postures and duration can increase the risk injury. Maximum Force Guidelines to take into consideration by Wick & McKinnis (1998): –Pinch Grip max of 8 lbs (3.6 kg) –Power Grip max of 25 lbs (11.3 kg) –Push max of 24 lbs (11 kg) –Pull max of 18 lbs (8.2 kg) –Static Force Exertion max of 60 seconds
Posture Proper Neutral Posture consist of: –Spine in 3 natural curves (back straight) –Arms & legs parallel to the torso (arms & shoulders down to the side, legs straight) –Elbows, hips, & knees may be at 90 degrees or more (elbows bent, body sitting) Awkward Postures –Are often caused by misalignment between the users body/joints and the accessories and/or computer components –Occurs when the body moves out of a neutral sitting/standing position Awkward postures that can lead to injury are: –Reaching to pick up loads –Twisting while lifting More than 60 seconds in an awkward posture may become a risk factor, such as: –Working overhead –Bending over to floor/ground –Working with wrist bent or typing at the computer
Duration Defined as maintaining a task or position for an extended time There are various forms of duration –Short Duration: Occurring less than 1 hour a day –Moderate Duration: Occurring 1-2 hours a day –Long Duration: Occurring more than 2 hours a day Examples of duration that produce higher risks: –Prolonged sitting and standing with no rest/stretch breaks increases the risk of low-back pain –Holding arms over head or arms/elbows extended in a fixed awkward position for a long duration becomes a risk factor –Sustaining a fixed task or position for long periods of time decreases blood circulation
Contact Stresses Defined as pressure of the soft tissue and skin against any hard surface Contact stress combined with force and repetition increases risk factor Examples: –Resting wrist or forearm over the edge of the work tables –Legs lose circulation by contact with edge of a chair –Using ones hand as a hammer, such as compacting items or pushing down on a stapler –Working on knees without cushions Sustaining a fixed position for long periods of time decreases blood circulation and may damage tissue or a nerve Examples: –damaged ligaments leading to tendonitis –damaged median nerve leading to carpal tunnel syndrome
Psychosocial factors Work-related job stressors as seen in: –High mental demands –Workloads and deadlines –Low job control –Poor social support Non work-related stressors may include: –Depression and anxiety –Symptoms of psychological distress –Home problems There is increasing evidence that psychosocial factors related to job and work environment play a role in the development of work-related MSDs of the UE and back. Studies have shown that psychosocial demands may produce increased muscle tension and exacerbated task-related biomechanical strain (National Institute for Occupational Safety and Health, 1997). Psychosocial demands may affect awareness and reporting of MSD symptoms, and/or perceptions of their cause.
Part II Summary Risk factors that contribute to MSDs within the workplace are: 1.Repetition 2.Force 3.Posture 4.Duration 5.Contact Stresses 6.Psychosocial A combination of these risk factors can increase the likelihood for injury
References Claiborne, D. K., Powell, N. J. & Reynolds-Lynch, K. (1999). Ergonomics and cumulative trauma disorders: A handbook for occupational therapists. San Diego: Singular Publishing Group, Inc. Konz, S. & Johnson, S. (2004). Work design: Occupational ergonomics. Scottsdale, AZ: Holcomb Hathaway. National Institute for Occupational Safety and Health (1997). Musculoskeletal disorders and workplace factors: A critical review of epidemiologic evidence for work-related musculoskeletal disorders of the neck, back, upper extremity, and low back. Retrieved from 141/ergotxt1.htmlhttp://www.cdc.gov/niosh/docs/ /ergotxt1.html Department of Business and Consumer Business Oregon OSHA (no date). Introduction to Ergonomics: How to indentify, control, and reduce musculoskeletal disorders in your workplace. Retrieved from University of Oregon, Labor Education and Research Center, & Oregon Occupational Safety and Health Administration (2008). Applied Ergonomics for Long Term Care [PowerPoint slides]. Retrieved from Wick, J. & McKinnis, M. (1998). A structured ergonomics design review process. In S. Kumar (Ed.), Advances in Occupational Ergonomics and Safety (pp ). Amsterdam: IOS Press.