Let's consider again the image of the overflowing glass. The load on the tissues is due to what you do, in which posture, for how long and in which psychological state: activity, posture, duration, stress. The glass overflows when the load on the tissues is durably higher than the evacuation.
The risk vector "activity, posture, duration, stress" is aggravated by
- extrinsic risk factors (that can be fixed by an external person): bad ergonomics, cold, draft, clothing, high workpace, etc.
- intrinsic risk factors, which are related to the (conscious or unconscious) that you make of your own body: unhealthy natural posture, inability to recognize or solve extrinsic risk factors, overweight, etc.
The load is evacuated when you relax and sleep.
Finally, the capactiy of the tissues (size of the glass) is determined by your physical, medical and psychological condition. It is partially genetically determined, but also partially influenceable
Read more: Recognizing WRMSD / Cost of WRMSD / Risk factors