"For the shoulder, a relaxed, neutral posture is one in which the arm hangs straight down by the side of the torso. As the arm is flexed, abducted, or extended, the included angle between the torso and the upper arm increases." Studies have linked awkward postures and shoulder tendinitis. Source: NIOSH Publication No. 97-141.
"Studies that examined force or forceful work or heavy loads to the shoulder, or described exposure as strenuous work involving the shoulder abduction, flexion, extension, or rotation that could generate loads to the shoulder region were also included. Most of the studies that examined force or forceful work as a risk factor for shoulder symptoms or tendinitis had several concurrent or interacting physical work load factors.
"There is evidence for a positive association between highly repetitive work and shoulder MSDs. The evidence has important limitations. Only three studies specifically address the health outcome of shoulder tendinitis and these studies involve combined exposure to repetition with awkward shoulder postures or static shoulder loads." Studies usually defined repetition, or repetitive work, for the shoulder as work activities that involved cyclical flexion, extension, abduction, or rotation of the shoulder joint. Source: NIOSH Publication No. 97-141: Chapter 3. Image by Suat Eman
More than 20 epidemiologic studies that have examined workplace factors and their relationship to shoulder musculoskeletal disorders (MSDs). The 3rd chapter of NIOSH Publication No. 97-141: titled Musculoskeletal Disorders and Workplace Factors examiners this relation. Image by Graur Razvan Ionut