Repetitive Stress Injury (RSI) is a kind of catch all phrase for many conditions, including:
Carpal Tunnel Syndrome
Tenosynovitis / DeQuervain’s Syndrome
Thoracic Outlet Syndrome
Myofascial Pain Syndrome
Chronic Sprain / Strain
Repetitive Stress Injuries occur from repetitive movements involving a specific set of muscles and joints. Mechanical Onset RSI (MORSI), also known as mouse arm disease (MAD), is a mouse-related musculoskeletal injury that affects millions of people around the world and costs employers and insurers billions of dollars. As we spend increasing amounts of time at our computer workstations, we need to be aware of how the design and arrangement of our equipment can impact our chances of acquiring a mouse-related musculoskeletal injury.
How Do I Avoid a Mouse-Related Musculoskeletal Injury?
The feature photo above is an excellent example of how NOT to use your mouse. The following tips should help you avoid a mouse-related musculoskeletal injury. These same posture principles apply to other input devices (e.g., trackball, touchpad, pen, digitizing puck etc.). Postural variation is a key factor for good ergonomics. Try to regularly vary your posture when you work with a mouse, and in this way you will help to minimize the risk of ergonomic problems. Remember, the best ergonomic mice are designed to allow you to vary your posture while working with the mouse.
Mouse Grip – Hold the mouse gently when moving it over a mousing surface. Cup your hand over the mouse, almost floating, without allowing the mouse to support the weight of your arm. Gripping the mouse tightly will strain the muscles in your arm and hand, which could lead to a mouse-related musculoskeletal injury. Frequent breaks should also be taken and arms stretched to boost circulation and re-oxygenate the hand and finger muscles.
Mouse from the Elbow – The human wrist was not designed for a computer mouse. Operating a mouse is awkward and becomes uncomfortable, because the wrist is turned up to 90 degrees from its most comfortable natural resting position. Any bending of the wrist, either to the side or up and down, can lead to tendon damage or other mouse-related musculoskeletal injury. To help avoid a mouse-related musculoskeletal injury, make controlled mouse movements with the entire lower arm, using your elbow as the pivot point and keep your wrist straight and neutral.
Optimal Mouse Position – The most up-to-date studies show that a slightly reclined sitting posture with the hips flexed at 100 to 115 degrees is ideal if you have to sit at a desk. So, sit back in your chair, relax your arms then lift your mousing hand up, pivoting at the elbow, until your hand is just above elbow level. Your mouse should be positioned somewhere around this point. Don’t use a mouse by stretching to the desk or out to the side of a keyboard. This stresses your back by reducing the angle of your hips and increases your chance of getting a mouse-related musculoskeletal injury.
Protect Your Wrist – Your wrists should never be in direct contact with any surface, including wrist rests and mouse pads. Instead, use the base of your palms to support the weight of your hands and arms in between mousing and typing to keep pressure off the sensitive carpal tunnel area in the wrist. This will help reduce the risk of a mouse-related musculoskeletal injury.
Avoid Restricting Circulation – Blood circulation is responsible for the action that moves nutrients, gases and wastes to and from cells, and helps stabilize body temperature and pH to maintain harmony. When blood vessels constrict, blood does not flow properly. Many people have exposed blood vessels near the skin at the wrist, where the pulse is often taken. Any pressure in this region will disrupt circulation into the hand and this will cause constriction in those blood vessels, which can cause hands and fingertips in the mouse hand to become cold. This can lead to a mouse-related musculoskeletal injury like Carpal Tunnel Syndrome, Arthritis, Raynaud’s, DeQuervain’s, or Tendonitis.
Don’t Use a Wrist Rest – Don’t use wrist rests or splints while typing, experts warn. Research has shown that using a wrist rest doubles the pressure inside the carpal tunnel. According to Professor Alan Hedge, Cornel University, the floor of the tunnel is a more flexible ligament that transmits external pressure changes directly into the carpal tunnel. Are you already suffering from Carpal Tunnel Syndrome (CTS)? One way to find out is by performing a test called “Tinel’s sign”, which simply involves tapping on the palmar surface of the wrist, which is enough to cause tingling and numbness in someone developing CTS.
Avoid Restricting Arm Movement – With a softly padded wrist rest, especially one that is rounded, or a soft chair arm rest the forearm becomes “locked” into position. Mouse movements should be made using the elbow as the pivot point, not the wrist. Too much wrist movement increases intracarpal pressure, leading to a mouse-related musculoskeletal injury.
Mouse Shape – Choose a mouse design that fits your hand, but is as flat as possible to reduce wrist extension. Don’t use a curved mouse. Use a larger, symmetrically shaped mouse, such as the Whale mouse or the Perfit mouse, which encourage arm rather than wrist movements or that encourage postural variety and one or two-handed use. Pen-based mice designs also allow a more comfortable grip. Some types of mouse palm support can be attached to the mouse, such as the Mouse Bean.
Load sharing – If you want to load share between your right and left hands, using the mouse for some of the time with each hand, you need to choose a mouse platform that can easily be configured to the left and/or right and a symmetrical shaped mouse that can be used by either hand.
Other Input Devices
Whether you choose a different mouse design, trackball, joystick, pen, touchpad, multitouch pad, or some other input device, make sure that you position it comfortably and that your wrist stays in a neutral position when using the device to avoid a mouse-related musculoskeletal injury.
How to Position Your Mouse in Your Workspace
Right-handed and left-handed mouse users should position a flat mouse platform, 1-2″ above the keyboard and over the numeric keypad – you can easily move it out of the way if you need to access these keys. With a downward sloping mouse platform, position this close to the side of the keyboard so that you can use the mouse in a neutral wrist position. However, if you are left-handed and have a right-handed keyboard, with the numeric keypad on the right, your best bet would be to use an angle-adjustable mouse platform placed immediately to the left side of the keyboard, and position it so that your left wrist is neutral. Mouse platforms are commercially available. If you require assistance choosing a mouse platform, please call Accredited Rehabilitation Consultants.
Accredited Rehabilitation Consultants not only provides ergonomic evaluations and ergonomic consulting, we also can help you get set up with the ergonomic equipment you need to prevent costly injuries in the workplace. See our Ergonomic Equipment page for more information on how we can help you make appropriate ergonomic selections for your workplace. We have relationships with many manufacturers and will recommend the best options regarding ergonomic equipment on the market.
An industrial injury is a repetitive or specific work-related musculoskeletal disorder (MSD) or an injury where pain interferes with normal work activities or daily living activities. Industrial injuries can occur suddenly by means of a workplace accident or over time as a result of many factors, including:
Repetitive Stress Injuries (RSIs) can occur when a worker performs a task that uses the same large or small muscles over and over, with little chance for rest or recovery;
Risk factors that increase the chance of RSIs include:
Lack of variety in job tasks;
The worker not being accustomed to the task, and
New workers who have not be sufficiently instructed on how to safely perform the task.
Force/Gripping injuries can occur when:
Workers grasp, tools or object that are too large, odd-shaped, vibrating or an awkward shape.
When the worker is wearing bulky gloves or the worker’s hands are cold.
When workers use a pinch grip to grasp small objects.
Hand and wrist tendons and muscles tire much quicker when workers use a pinch grip rather than a power grip. And much more pressure is exerted on soft tissue, such as muscle, tendons, ligaments and nerves. Over time, these can cause debilitating industrial injuries.
Awkward Posture/Kneeling injuries can occur when any joint of a worker’s body bends or twists excessively, outside a comfortable range of motion. This puts stress on muscles, tendons and joints.
Static Posture injuries can occur when an awkward posture is held for a long time, causing muscle fatigue, because:
Fatigued muscles ache because of a lack of circulation from holding a static posture for too long.
Fatigued muscles can lead to increased discomfort, spasms and even injury.
Local Contact Stress occurs when:
A hard or sharp object comes in contact with the skin.
A worker strikes objects sharply with the hand, foot, knee or other body part.
Local contact stress can irritate soft tissue and interfere with circulation and nerve function, especially when:
The hard object comes into contact with an area with little protective tissue, such as the wrist, palm, or fingers.
When the pressure is applied repeatedly or over a long period of time.
Vibration exposure can occur:
While using power tools in multiple occupations and settings, (e.g., automotive repair shops, construction work, engineering, dental care, etc.)
When hands are exposed to very high frequency vibrations, such as dental technicians and dentists.
The whole body being exposed to vibrations such as shocks, jolts, lateral sway and vertical bouncing, while driving equipment.
Vibration from power tools can place stress on the tissues of the fingers, hand and arms, which can cause such conditions as Hand-Arm Vibration Syndrome (HAVS), arthritis or tendonitis. It can also cause changes in muscle fibers, which can result in impaired grip force, reduced mobility and pain in the hand and arm. Whole body vibration (WBV) from driving puts stress on the feet, buttocks and spinal tissues, which can cause cumulative trauma, repetitive stress injuries, chronic wear and even sudden shock syndrome injuries.
What is an Ergonomic Injury?
Industrial injuries caused by ergonomic hazards are also known as ergonomic injuries. Ergonomic injuries are very commonplace now because industries require increasingly higher rates of production, which can result in such ergonomic hazards as:
Workers frequently lifting, carrying, pushing or pulling loads unassisted by fellow workers or devices;
Increasing specialization that require workers to perform repetitious functions or movements over extended periods of time, day after day;
Workers being required to work more than 8 hours a day, which leads to fatigue;
Workers being required to work quicker on fast assembly lines; and
Workers having to handle tools or objects requiring a pinch grip or excessive force.
Preventing Ergonomic Risks that Lead to Industrial Injuries
The likelihood of developing industrial injuries is dependent on the frequency and duration of exposure to ergonomic risk factors. The following are a few common ergonomic injuries and simple remedies that can reduce or eliminate them:
Electronic telephone head set, upright document holder.
Carpal Tunnel Syndrome (CTS)
Special keyboard, voice activation software.
Implement rest or stretch breaks, alternative task assignment.
Changing workstation layouts to minimize twisting, raising or lowering work surfaces and storage spaces to minimize reaching, bending and kneeling, providing proper seating for low level or kneeling work and providing knee pads for workers that need to kneel.
Repetitive Stress Injuries
Eliminating excessive force and awkward positions, providing safe and effective job procedures, allowing workers to rotate between workstations and tasks (job rotation).
Putting remedies in place alone will not reduce the risk of industrial injuries. Workers will also require proper training on how to perform their job duties safely and ergonomically.
Ergonomic Consulting Services in Los Angeles
An employer needs to take into consideration all aspects and areas of the workplace in order to develop a practical approach of proactive planning and assessment to reduce and eliminate industrial injuries. Accredited Rehabilitation Consultants can help. We employ a four-phase process of pairing low-cost, high-impact solutions to real problems.