The REBA grid, “Rapid Entire Body Assessment“, is an evolution of the RULA grid. The tool was edited by the same authors, Dr. L. McAtamney and Dr. S. Hignett, en 2000. It is more complete and allows to evaluate the posture of the whole body (144 in total, static, dynamic, rapid movement…). On the other hand, it does not take into account the phenomena of vibrations or even the duration of the actions. For these reasons, the tool is more suitable for the service sectors than for the work done in production.
The principle of the method is based on the observation of the operator’s work cycle and then on the evaluation of the postures adopted during these cycles. At the end of the evaluation, the REBA grid indicates the level of risk and it is inferred whether or not improvement actions are necessary and the level of urgency of implementation of these actions.
Generally speaking, the method divides the body into 2 segments:
- Group A represents the upper part of the body (shoulder, elbow, handle).
- Group B is part of the lower body (leg, neck, trunk).
Each part is recorded individually and is translated via a table into one note per group. Finally, a global note is assigned according to the notes of groups A and B and the constraints applied (type of effort…).
The process is as follows:
- Determine the work cycle to be observed.
- Select the posture to be evaluated.
- Decide which side of the body is going to be evaluated or if too complex, evaluate both sides at the same time.
- Determine the score for each side of the body.
- Get the overall score and the level of risk associated with it.
- Review the scoring of each part of the body to determine where the actions are needed.
- Redesign the Workstation and introduce improvements towards the identified ergonomic risks.
- Once the changes are made, re-evaluate with the REBA grid to validate the results.
For the evaluation, it is advisable to help yourself with photos or videos of the different postures observed.
1-Group A evaluation
This is to evaluate the upper body posture on which we will affix an adjustment variable. We will identify a note for:
- The shoulders: The score depends on the position of the arms as well as an adjustment variable (seated position…).
- Elbows: The score depends on the angle that the forearm makes with the upper arm.
- wrists: The score depends on the position of the wrist in terms of bending but also of rotation.
Once the scores have been identified for these 3 parts of the body, we identify the overall score of the Group a posture in a table.
The REBA grid proposes to evaluate the posture relative to the object we have to grasp. The evaluation grid takes into account the simplicity to grasp the object in question.
3-Group B evaluation
This is to evaluate the posture of the lower body on which, we will affix an adjustment variable. We will identify a note for:
- The neck: The score depends on the position of the neck (flexion or extension) as well as an adjustment variable (rotation…).
- The trunk: same as for the neck, the score depends on the position of the trunk in relation to the adjusted legs of the trunk rotation.
- Legs: The score depends on the level of stability of the support or, if one works in an unbalanced way, adjusted from the angle of knee bends.
Once the scores have been identified for these 3 parts of the body, we identify the overall score of the posture of group B in a table.
4-Score of effort and load
The level of stress of the posture is assessed. So for actions of pushing, lifting, pulling…, we take into account the level of stress in Kg that one will adjust with the shocks…
Getting the final score will be done in 2 times:
- The value for all of our previously identified scores is searched in the table.
- This score is adjusted with the level of activity observed: frequency…
Interpretation of the score
This very playful method does not allow to accurately evaluate tasks related to small Handlingof objects with hands. It does not allow us to evaluate tasks requiring long travel or very varied and unpredictable tasks. It also lacks precision to analyze the frequency of efforts or certain postures very specific to the production.
The method, a little more general than the method RULA, can be used to evaluate most tasks.
Hignett S, McAtamney (2000)-L. Rapid Entire body assessment (REBA)
Hignett S, McAtamney (2006)-L. REBA and RULA: whole body and upper limb assessment tools.
E. P. Takala (2010) – Systematic evaluation of observational methods assessing biomechanical exposures at work