The method is to evaluate the task for each of the 4 muscle groups that are the lower limbs, the back, the neck/shoulders and the arms/wrists/hands. For each of them have evaluated:
- Cycle Time* : This is the duration of the operation in such a time as we repeat X times over a given time. Depending on the operation, the cycle time is different depending on the body parts.
- the Duration* : This is the average time that happens in 2 breaks. In other words, the time we spend doing the task without any significant interruption.
- The Force * *: This is the force to carry out the task. This force depends on the abilities of the person as well as the regions of the body.
- Speed * *: Speed is a risk factor for additional MSD . One evaluates by region of the body.
- The Posture: Of course, inflections, twists… are factors that increase exposure to MSD. They are evaluated by regions of the body.
Beyond that, 3 other criteria are evaluated in 1-fold for the whole body:
- Total time: This is the total time per normal working day that we devote to the task we are evaluating.
- The Vibrations: Vibrations are aggravating factors. They are evaluated at once for the whole body.
* The duration and cycle time are evaluated independently of each other. On the other hand, the score will be combined because it is considered that a task with a very low cycle time but performed over a long duration is more at risk than a task with a long cycle time but carried out over a short duration.
* * There too, strength and speed are factors that we will evaluate independently of each other but that we will combine in a table to have the final score. It is considered that the same statically applied effort is less risky than if it is applied with movement.
Once all the scores have been obtained, we will carry out by regions of the body an evaluation of the risk MSD. The interpretation is binary, ” at risk ” or ” to be monitored “, and 3 criteria per body regions are to be taken into account to validate a situation at risk. If one of them is validated, then the situation is considered ” at risk “:
- The combined strength and speed score is 5
- The sum of the score ” Strength/Speed ” and posture is at least 8.
- The sum of all the scores is more than 15