A workers posture can either be good, poor or awkward. It is not always the choice of the employee to have an awkward posture, but can be because of their environment or tools.
Poor posture has a big impact on the muscles. If you are holding the correct posture when performing a task, you will be optimizing the way your muscles work together to create your movement. The blood supply will be plentiful to the muscles being worked, and risk of fatigue is minimal within reason.
When you have poor posture, the large and small muscles are unable to function in the order and way they prefer. Muscles begin overcompensating for each other and the extra strain causes certain fatigue. Correct posture means that the larger, stronger, more enduring muscles take the majority of the work, and the smaller ones merely assist. With incorrect posture the smaller muscles sometimes have to do all the work and blood supplies are impinged on resulting in continuous fatigue.
Any movement or action when repeated or prolonged whilst in an awkward posture can easily cause problems in referring areas of the body. If you reach, twist, bend, lift up, crouch, tightly grip or hold something in place for a length of time, you must assess carefully the following: