Avoiding and minimising risks from poorly designed tasks and workstations

The main risk factors for work-related upper limb disorders fall under three headings: task, environment and equipment.

Task-related factors

Repetition

• Wherever possible, alternate activities often during the day. Rotate heavy or repetitive tasks with lighter, less repetitive ones.
• Use diverging conveyors off a main line so that tasks are less repetitive.

Working posture

• Redesign tools so that they allow neutral postures.
• Reposition a work table to remove long or excessive reaches and allow neutral posture.
• Fit diverters on conveyors to direct materials towards the worker and remove excessive leaning or reaching.
• Keep the back and neck erect with the shoulders relaxed. Minimise twisting and bending. Position equipment and work so that the body is directly in front of, and close to, the main work.
• Arrange the work to keep shoulders relaxed, arms comfortably supported and wrists in a suitable neutral posture. Adjust the chair, work surface and equipment for the task and individual, with foot support where needed; one prescribed elbow angle does not suit every activity.
• Reduce sustained or repeated extreme wrist positions and force through task and tool design. There is no universal 15-degree safe zone that guarantees protection.
• Avoid bending the neck forward for long periods. If typing from a manuscript, put the document in a holder beside or below the screen.
• Avoid static positions for long periods. Muscles tire faster when held in one position, so keep moving to improve circulation.

Force

• Use a device to lift and reposition heavy objects so that less force is needed.
• Reduce the weight of the load to limit force.

Duration of exposure

• Set up systems that rotate workers away from tasks, to limit continual exertion, repetitive movement and awkward postures.
• Design a job rotation system in which employees move between jobs that use different muscle groups.

Twisting

• Avoid twisting wherever the task allows. Any twisting action, such as turning the wrist with a screwdriver, adds to the risk of ULDs.

Rest

• Provide extra short breaks between the scheduled ones.
• Create more micro-breaks for workers who must sit or stand all day. These give a chance to sit down and rest, or stand up and stretch, as the situation requires.

Psychosocial factors

• As well as the physical aspects of work, take account of psychosocial risk factors. They affect how workers respond psychologically to their work and workplace. High workloads, tight deadlines and lack of control over work and working methods, for example, can make people more likely to develop and report ULDs.
• Suggest a stretch-and-flex programme at the work site. It also gives a chance for team bonding and communication while preparing each person's body for the work ahead.

Environment-related factors

Temperature

• When it is too cold, or when we touch cold materials, our hands can become numb. Numb hands make us more likely to misjudge the force needed and use too much. A cold environment also makes the body less flexible, so every movement and held position takes more effort, and MSDs become more likely.
• When it is too hot and humid, workers tire faster and may be more open to injury.
• Improve the working environment, since cold and draughts add to discomfort, and reduce exposure to uncomfortable temperatures.
• Provide suitable PPE and local heating or cooling where a comfortable temperature cannot be kept.
• Do not place workstations too near air vents.
• Avoid metal-handled tools in cold environments.

Working space. If there is not enough space to do the job, the strain on the body rises and so does the risk of MSDs.

• Change the workstation layout to improve posture, particularly when workers apply force.
• Consider height-adjustable workbenches, or place tools and materials within short reaching distance.

Lighting and glare

• Make sure overall lighting is adequate, or provide suitable task lighting.
• Avoid reflections and glare by moving lights, fitting blinds to windows or moving workstations.

Equipment-related factors

User requirements

• Provide suitable training and information.
• Consider involving workers in decisions about their work.
• Encourage workers to report any upper limb discomfort promptly so it can be dealt with. A body map may help to identify problem areas.
• Use the largest joints and muscles to do the job.
• Use two hands to lift rather than one, even for light objects and tasks, and avoid lifting with the forearm fully pronated (palm down) or supinated (palm up).

Equipment design

• Make sure tools and equipment fit the workers' hands and suit the task. A large shaped handle on a scraper, for example, makes it easier to hold and use.
• Select the correct tool, handle and size for the task and required force. Do not improvise extensions or exceed the tool's intended use; extra length can create loss of control or overload.
• Use vices, clamps or jigs to hold objects steady, so that the hand does not have to keep a forceful grip.

Equipment adjustability

• Make sure workstations are at a suitable height for comfortable work, with suitable chairs and footrests. Consider adjustable workstations.
• Position the keyboard and pointing device so they can be used comfortably without excessive reaching or wrist bending. Use adjustment where needed; no single tray or tilt setting suits every user.
• Tilt containers or objects so the wrist does not have to bend to pick things up.

Summary notes for Element 6 · Cheat sheet · Glossary. A study aid, not published or endorsed by NEBOSH.