Guidance for safety reps
Identifying potential RSI risks in the workplace
International RSI Awareness Day 2002
Spotting the risks of RSI
Repetitive strain injuries, or RSI (known by the Health and Safety Executive as upper limb disorders) affect hundreds of thousands of workers every year in Britain, and millions around the world. This TUC guidance for union workplace safety reps is being launched on International RSI Awareness Day 2002 (the last day in February - the only non-repetitive date of the year), to help safety reps identify which jobs in their workplace carry the highest risk of RSI. It uses a 'risk filter' designed by the Health and Safety Executive (HSE) which identifies those tasks in their workplace which will require further assessment of the risk of RSI. The carrying out of a full risk assessment does not form part of this exercise. Where the need for such assessments is identified then this should be done using the additional guidance contained in HSG(60) (REV) launched on 28 February 2002 and available through the HSE website at from HSE Books.
The TUC is urging safety reps to use this filter on International RSI Awareness Day and beyond as part of their legal right to conduct safety inspections. Where possible, this exercise should be conducted in partnership with management, so that the analysis of the likelihood of risks is shared, and the action to address those risks (starting with a full risk assessment), is done in partnership.
Identifying problem tasks
Carrying out a detailed assessment of every job could be a major undertaking, and might involve unnecessary effort. To help identify situations where a detailed assessment is necessary, the risk filter will show you whether key risk factors are likely to be present in a task, and indicates whether a more detailed risk assessment may be necessary. Where the filter identifies several risk factors in combination, the risk of RSI is likely to be greater.
There are two main approaches you can use to identify if you have a problem in your workplace.
Firstly safety reps and managers can look for any signs of problems or symptoms amongst the workforce - the TUC advocates the use of body mapping, which encourages workers to discuss their work and the effect it has on their health - further details are available on the Hazards magazine website at www.hazards.org/diyresearch/index.htm
Secondly, you can observe work tasks themselves to see if risk factors for RSI are present. This can be done using a simple initial assessment of risks such as the risk filter. Other sources of information that may help include expert advice, industry standards and legislative standards.
Warning signs
Warning signs can indicate the presence of hazards relating to RSI. Signs of existing RSI problems can include:
- injury and illness records;
- jobs which workers are reluctant to do;
- jobs where workers complain of discomfort;
- workers having made adaptations to workstations, tools or chairs;
- workers requesting to be re-deployed or taken off a job;
- splints or bandages being worn; and/or
- use of painkillers.
Guidance on using the risk filter
The aim of the risk filter is to set out an approximate boundary below which the risk of RSI is likely to be low. The risk filter work sheet is provided as an aid to risk assessment. It has been developed by the HSE from the scientific literature and from expert opinion. As such, it does not set out precise exposure limits, but should help you to identify the potential risks and possible measures to reduce them. Other methods of assessment are available and may be equally appropriate in assessing the level of risk of RSI.
Use of the risk filter will help to identify those situations where a more detailed assessment is necessary. (Please note that certain risk factors have been purposely omitted in the filter in order to provide a useable first stage, screening tool.)
Before undertaking applying the risk filter you should read the guidance on risk factors. In order for your application of the filter to be effective you should:
- involve all people involved with the tasks to take advantage of their intimate knowledge of the work;
- explain to the worker(s) what you are doing prior to assessing a task. You should always emphasise that the assessment is of the task and not the worker’s performance;
- be aware that if you identify any tasks that relate to display screen equipment or involve manual handling you will also need to refer to specific guidance on the relevant regulations to assess these;
- make sure that you have spent some time observing the task and talking to those involved, and what you are seeing is representative of normal working procedures;
- complete the assessment in the workplace (where possible, and if it is safe to do so);
- focus on the upper limb at each step ensuring you consider the fingers, hands, wrists, arms, shoulders and neck;
- where the risk filter indicates further action move on to stage two of the assessment using the risk assessment worksheets contained in HS(G) 60 (REV).
Risk filter procedure
Completing the risk filter work sheet involves:
- recording the basic details of the task such as the date, name of the task, the assessor and task description;
- probably using a separate risk filter work sheet for each task;
- going through each step in turn and placing a tick in each box where you observe examples of these risks;
- planning a more detailed risk assessment if any of the risk factors are ticked;
- identifying those tasks with the most risk factors (the more the greater the risk) to help in prioritising tasks for the second stage risk assessment.
Risk filter work sheet
Task:
Assessor:
Date:
If you answer yes to any of the steps, you should then make a full risk assessment of the job. Remember to consider each of the body parts of the upper limbs (fingers, hands, wrists, arms, shoulders and neck).
Step 1: Signs and symptoms
Are any of the following present?
- medically diagnosed cases of RSI in this work
- complaints of aches or pains
- improvised changes to work equipment, furniture or tools
Step 2: Repetition
Are any of the following repetitive elements present for more than two hours total per shift?
- repeating the same motions every few seconds
- a sequence of movements repeated more than twice per minute
- more than 50% of the cycle time involved in performing the same sequence of motions
Step 3: Working postures
Are any of the following working postures present for more than two hours per shift?
- large range of joint movement such as side to side or up and down
- awkward or extreme joint positions
- joints held in fixed positions?
- stretching to reach items or controls?
- twisting or rotating items or controls
- working overhead
Step 4: Force
Are any of the following forces applied with a sustained or repeated application of force for more than two hours total per shift?
- pushing, pulling, moving things (including with the fingers or thumb)
- grasping/gripping
- pinch grips ie holding or grasping objects between thumb and finger
- steadying or supporting items or work pieces
- shock and/or impact being transmitted to the body from tools or equipment
- objects creating localised pressure on any part of the upper limb
- sustained or repeated application of force
Step 5: Vibration
Do workers use any powered hand-held or hand-guided tools or equipment or do they hand-feed work pieces to vibrating equipment regularly (ie. at some point during most shifts)?
If you answer yes to any of the steps, you should ask your employer to make a full risk assessment of the job.
NB: This worksheet was developed by the HSE who use the term ULD (upper limb disorders) where the TUC would use RSI (repetitive strain injury).
Guidance to using the risk filter work sheet
Step 1: Signs and symptoms
Look for:
- actual cases of RSI in work;
- are you aware of increases in sickness absence, reports of problems?
- complaints of aches or pains;
- talk to managers, supervisors and workers;
- improvised changes to work equipment, furniture or tools;
- walk through the workplace to identify improvised changes;
- check with managers, supervisors and workers for 'difficult' jobs or those which have become more 'difficult' recently.
Step 2: Repetition
Check for frequent movements for prolonged periods. Examples may include repeated hand press operations, repeated triggering operations, repeated cutting actions, repeated handling etc.
A 'cycle' refers to a sequence of actions of relatively short duration that is repeated over and over, and is almost always the same. They are not necessarily associated with one single joint movement, (such as the elbow), but with movements of one or more parts of the limb (such as reaching, manipulating and placing an object). Cycles are not always clear-cut, and in such cases observers should look for similar actions that are repeated.
A simple task may consist of a sequence of movements which would be repeated and therefore form the cycle. A more complex task may consist of elements some or all of which may be distinct cycles.
Step 3: Working postures
Check for postures that are awkward and/or held for prolonged periods in a static or fixed position. Check fingers, wrists, hands, arms, shoulders and necks. Make a sketch using a stick figure if this helps. Remember: The more the joints deviate from their neutral position, the greater the risk.
Step 4: Force
Check for sustained or repeated application of force.
Step 5: Vibration
Make a note of the type of vibrating tools or equipment such as grinders, polishers etc. that are in use.
Other factors
You should also be aware that psychosocial and working environment factors (such as high job demands and lack of control, cold and lighting) could further increase the risk of RSI.
NB: This guidance was developed by the HSE who use the term ULD (upper limb disorders) where the TUC would use RSI (repetitive strain injury).
RSI risk factors
Risk factors which affect RSI can be thought of in terms of task, environment, or worker-related. The principal RSI risk factors are:
Task-related factors
Environment-related factors
Worker-related factors
Each of these risk factors, including their definitions and why they create the risk of RSI, is discussed in more detail below.
Risk factors commonly interact with each other in creating the overall risk of RSI. For example, the task of gripping a heavy power tool with a large handle for six hours would result in an awkward, forceful gripping posture and exposure to vibration over a prolonged period. Therefore working postures, duration, force and working environment are all risk factors for injury in this task.
In contrast, if this task was only done for a short period in each shift, the risk of injury may not be high. This is despite the fact that risks from working postures, force and vibration are still present.
Generally, there is an increased risk of injury when there are a number of risk factors acting in combination. However, one risk factor acting alone can create an unacceptable risk of injury if it is sufficiently great in magnitude, frequency or duration.
Repetition
Work is repetitive when it requires the same muscle groups to be used over and over again during the working day and use of frequent movements for prolonged periods. Rapid or prolonged repetition may not allow sufficient time for recovery and can cause muscle fatigue due to depletion of energy and a build up of metabolic waste materials. Fast movements and acceleration require high muscle forces.
Working posture
Working postures can increase the risk of injury when they are awkward and/or held for prolonged periods in a static or fixed position.
Awkward postures
An awkward posture is where a part of the body (eg limb and joints) is used well beyond its neutral position. A neutral position is, for example, where the trunk and head are upright, the arms are by the side of the body, forearms are hanging straight or at a right angle to the upper arm, and the hand is in the handshake position. When a person's arm is hanging straight down with the elbow by the side of the body, the shoulder is in a neutral position. However, when employees are performing overhead work (eg repairing equipment or accessing objects from a high shelf) their shoulders are far from the neutral position.
When awkward postures are adopted, additional muscular effort is needed to maintain body positions, as muscles are less efficient at the extremes of the joint range. Resulting friction and compression of soft tissue structures can also lead to injury.
Static postures
Static postures occur when a part of the body is held in a particular position for long periods of time without the soft tissues being allowed to relax. When holding a box, for example, it is likely that the hands and arms are in a static posture. Static loadings restrict blood flow to the muscles and tendons resulting in less opportunity for recovery and metabolic waste removal. Muscles held in static postures fatigue very quickly.
In both the above types of posture (awkward and static), the risk of RSI will be related to the number of times the posture is repeated, and/ or the length of time it is held. As with all the risk factors for RSI, the impact of the working posture needs to be understood in relation to other risk factors.
Force
Force can be applied to the muscles, tendons, nerves and joints of the upper limb by:
- handling heavy objects when performing tasks, ie an external load;
- fast movement or excessive force generated by the muscles of the body - often to be transmitted to an external load, eg trying to undo a stiff bolt; or
- local force and stress from items coming into contact with parts of the upper limb, such as the handle of a pair of pliers digging into the palm of the hand.
The level of force that is generated by the muscles is affected by a number of factors including:
- working posture: the level of muscular effort required increases when a part of the body is in an awkward posture;
- the size and weight of objects being handled;
- the speed of movement: as extra force is needed at the beginning and end of fast movements such as hammering; and
- vibrating tools or equipment: as operators need to use increased grip force in working with vibrating equipment.
Use of excessive force can lead to fatigue and if sustained, to injury, either through a single-event strain injury or through the cumulative effect of the repeated use of such force. Local force and stress can also cause direct pressure on the nerves and/or blood vessels and increase the risk of discomfort and injury.
Force in gripping
The need to grip raw materials, product or tools is a potential risk factor if excessive force is used. The amount of force required to grip can be influenced by, the type of grip used, the posture of the wrist, exposure to cold and vibration and the effects of wearing gloves.
The force required to grip objects is also dependant upon the material or item being gripped. For example, a screwdriver handle with a flexible grip requires less force when being used than one with a harder handle. The size of the object being gripped can also affect the force required. For example, pliers with a wide span have a greater impact on grip than those with a narrower span.
Muscle force is greatest when a power grip (eg gripping a handle in the palm with fingers and thumb) is used as this allows a large surface area of the hand to be utilised. The strongest grip strength occurs when the wrist is close to the ‘handshake’ position or is slightly bent upwards.
Duration of exposure
Duration refers to the length of time for which a task is performed. It includes the length of time that the task is undertaken in each shift, plus the number of working days the task is performed (eg 4 hours per day, five days per week). Duration is an important concept in assessing the risk of musculoskeletal disorders. Building such a complex factor into a simple risk filter is difficult. More than 2 hours total per workday have been used as basic building blocks of exposure time throughout the guidelines in the risk filter. It must be emphasised however that the 2 hour period is not a limit and should be applied pragmatically.
It is generally accepted that many types of upper limb disorders are cumulative in nature. Therefore, when duration time is increased the risk of injury is increased. This is because when parts of the body undertake work for periods without rest, there may be insufficient time for recovery. Consequently, time for the individual’s body to recover from a specific task or tasks is important.
Short exposures are unlikely to create significant risk of injury, except where the task is exceptionally demanding and/or the worker has not been allowed to build up to its demands over a period of time. This can occur after return to work from holidays or with an increase in work pace.
Working environment
Working environment refers to aspects of the physical work environment that can increase the risk of RSI. This includes factors such as vibration, cold and lighting.
Vibration
Exposure to hand-arm vibration results from the use of hand-held/guided power tools and equipment or fixed machinery such as bench grinders where the workpiece is held by the worker. Vibration can increase the risk of RSI and is known to cause vibration white finger and carpal tunnel syndrome, loss of sense of touch or temperature, painful joints and loss of grip strength. Information about the dose (ie vibration magnitude and exposure time) of vibration is needed in order to accurately assess the risk.
Cold
Working in cold temperatures, handling cold products or having cold air blowing on the hands and wrists can place additional demands on the body as well as possibly requiring the use of personal protective equipment (which can compound the risk by requiring additional force to grip). Exposure to cold can result in decreased blood flow to the hands and upper limbs, decreased sensation and dexterity, decreased maximum grip strength and increased muscle activity (which is part of the body’s natural response to being cold).
Lighting
The visual demands of the task are an important consideration, since a worker’s posture can be largely dictated by what they need to see. Dim light, shadow, glare or flickering light can encourage workers to adopt a bent neck and poor shoulder postures in order to see their work, thereby exacerbating the effects of other risk factors.
Psychosocial factors
It is now considered that psychosocial work characteristics are implicated in the onset of RSI. Psychosocial factors include certain aspects of work design, the organisation and management of work and the overall social environment in the workplace and can affect people’s perception of their working conditions and symptoms experienced. Important factors include:
- job stress leading to excessive pressure such as high job demands, time pressures and lack of control;
- lack of support from supervisors or co-workers;
- tasks requiring high levels of attention and concentration are related to increased muscle tension, changing thresholds for the perception of pain and fatigue.
Many of the effects of these psychosocial hazards are probably mediated by stress-related processes, and these in turn may interact with physiological changes in muscle and other soft tissues to bring about the onset of symptoms and disease. Psychosocial factors are also highly relevant in the maintenance of, and recovery from RSI pain.
Individual differences
All individuals are different and for biological reasons there may be some people who are more or less likely to develop an RSI. Individual differences may also have implications for employees reporting RSI type conditions. Where an ergonomic approach is followed, this should ensure that tasks are within the capabilities of the entire workforce. Some factors may increase the risk of developing symptoms. These include:
- new employees may need time to acquire the necessary work skills and/or rate of work;
- difference in competence and skills;
- workers of varying body sizes, ie height, reach etc. This can lead to adopting poor postures when working at shared workstations;
- vulnerable groups, eg older, younger workers and new or expectant mothers;
- health status and disability;
- individual attitudes or characteristics that may affect compliance with safe working practices or reporting of symptoms .
NB: This guidance was developed by the HSE who use the term ULD (upper limb disorders) where the TUC would use RSI (repetitive strain injury).
HSE Books contact details - tel: 01787 881165, fax: 01787 313995, web: www.hsebooks.co.uk
Report (3,500 words) issued 23 Feb 2002