Body postures determine which joints and muscles are used in an activity, as well as the amount of force
exerted. Poor postures place unusual or excessive
forces on components of the body.

(a)  

This refers to the amount of time a person holds a static position to perform a given task. The longer the same muscle or muscle group is used, the greater the likelihood of both localized and general fatigue

(a)  

Motions performed only infrequently, even if performed in an awkward position, seldom result in any bodily harm. However, as a particular motion becomes more and more frequent, the risk of injury increase

(a)  

A systematic process for identifying, analyzing,
and controlling workplace risk factors, often
for reducing musculoskeletal disorder

(a)