When employees perform tasks that involve long reaches, they are exposed to awkward postures—the postures of their shoulders and/or back—which deviate significantly from their neutral or strongest posture. Repeatedly performing tasks in such postures pose increased stresses on the joints and/or spinal discs. Muscles do not work as efficiently in awkward postures and the muscles must exert more physical effort to accomplish the task. This increased force contributes to muscle-tendon fatigue and strain. If frequent reaching is a part of the job, the stress on the shoulder may cause irritation and inflammation of the tendons, muscles, and shoulder joint. This, in turn, may place increased pressure on nerves and blood vessels, reducing the supply of blood to the affected muscles and tendons.
Ask why
Why are employees reaching behind, overhead, or across their bodies? Many times there is no logical reason except that is where tools and parts have always been located. In most cases, this can be easily corrected by moving frequently used items closer.
“Everyone performs best when working in an area directly in front of the torso called the comfort zone. This area is where we are the strongest, possess and execute the most control, and have the best visual acuity. In addition, working inside the comfort zone may also reduce the time necessary to perform a work activity because unnecessary movements are reduced or eliminated,” [Humantech, Inc. Applied Industrial Ergonomics v4.0, (Ann Arbor: Allegra Press, 2004), p. 71.].
When workstations are arranged with frequently used tools and parts within easy reach (graphic below), operators and materials have a shorter travel distance. Eye movements, hand movements, and body movements are reduced resulting in less effort and the likelihood of an injury occurring.