Table 3.

Classification according to criteria of injury mechanism and risk factors inherent to activities.

Classification		Criterion
		Mechanism/Risk Factors
MSD Type	Onset Mode	Mechanical Action	Mechanism of Tissue Injury/Tissue Integrity	Risk Factor
0	Late	−Tissue trauma due to a tolerable effort	Alteration of homeostasis with a mild inflammatory response	Absent
1	Sudden	−External direct trauma −Tissue trauma due to excessive effort	Traumatic, generating an episode of acute inflammation in healthy tissue	Physical Operational
2	Sudden	−External direct trauma −Tissue trauma due to excessive effort	A new episode of acute inflammation in tissue previously damaged or inflamed but not fully regenerated.	Individual physical Ergonomic Operational
3	Gradual	−Trauma in the inflamed or fibrous tissue that may occur with low-energy effort	Repeated episodes of inflammation over unregenerated tissue, maintaining a continuous process of chronic inflammation.	Individual physical Ergonomic Operational