TNO physical work load

TNO physical work load

assess risks, tackle issues

Welcome to the Working Posture Risk Assessment Tool (WRAP 1.0)


What is WRAP?

This working posture risk assessment tool can be used to determine the risk of developing musculoskeletal disorders (pain or malfunction in joints, ligaments and/or muscles) due to unfavourable working postures. The use of this method will enable you to:

  • gain insight into the health risks due to unfavourable postures
  • identify high-risk postures

The WRAP risk assessment tool can be regarded as the first step towards risk reduction and prevention. A detailed description of the stepwise approach involved can be found by clicking on the ‘download forms’ tab. WRAP can also be used to ascertain whether preventive measures have had the desired effect of reducing the risk of injury.

The assessment takes place per task, i.e. for all employees who perform that task, and not per employee, function or day. It is important to check whether there are functions that involve several risky tasks per day. In that case, it may be necessary to consult a kinesiologist (an expert in the physiological and mechanical aspects of human movement).


For which tasks?

The method is intended for the assessment of working postures during tasks:

  • that are performed during a working day and that take longer than 30 minutes per day (add all periods)
  • where the force exerted by 1 hand is less than 1 kgf or 10 N (approximately the weight of a package of sugar).

Examples of such tasks are driving a lorry, washing patients (by nurses), general dentistry work, sorting of products weighing less than 1 kg and quality checks.

The method is not recommended for the evaluation of computer-related work. Other methods that test the ergonomics of computer devices are recommended for this purpose.


For which employees?

This method is suitable for assessing risks for adult employees between the ages of 18 and 65, in all sectors of industry.


Who can use the method?

Potential users are those who are responsible for a company’s working conditions, such as prevention officers, working conditions coordinators, personnel officers, HR management staff or – in small companies – the director himself. Health and safety experts and working conditions services can also use the method. The method does not require any specific prior knowledge.


  • If large differences in task performance between workers or between working days exist, it is advisable to observe various workers on different working days. The assessment results can be averaged to calculate the overall risk assessment score.
  • The risk assessment should preferably be performed by a team of two persons rather than one single observer – especially when the assessment is performed for the first time. This generally leads to better results.

* WRAP 1.0 was developed on the basis of both scientific knowledge concerning high-risk working postures and expert opinion. The validity of the tool is still unknown, however. It is therefore important that the risk assessment should also involve a check for the presence of other health risk factors as well as risk factors for absenteeism from work.