Levels of evidence for interventions associated with positive effects were : Moderate evidence for arm supports ; and Limited evidence for ergonomics training plus workstation adjustments , new chair and rest breaks .
Levels of evidence for interventions associated with “ no effect ” were : Strong evidence for workstation adjustment alone ; Moderate evidence for biofeedback training and job stress management training ; and Limited evidence for cognitive behavioral training .
No interventions were associated with “ negative effects ” .
Conclusion It is difficult to make strong evidence d-based recommendations about what practitioners should do to prevent or manage upper extremity MSDs .
There is a paucity of high quality OHS interventions evaluating upper extremity MSDs and none focused on traumatic injury outcomes or workplace m and ated pre-placement screening exams .
Background Little is known about the most effective occupational health and safety ( OHS ) interventions to reduce  upper extremity musculoskeletal disorders ( MSDs ) and injuries .
Methods A systematic review used a best evidence synthesis approach to address the question : “ do occupational health and safety interventions have an effect on upper extremity musculoskeletal symptoms , signs , disorders , injuries , cl aims and lost time ? ”
Effects of keyboard tray geometry on upper body posture and comfort.
The effects of a downward-tilting ( DT ) keyboard tray on wrist posture , seated posture and self-assessed musculoskeletal discomfort were investigated in a field experiment . Thirty-eight professional office workers were studied . A pretest assessed how they typed using either a conventional keyboard on a desk or on an articulating keyboard tray , and with or without wrist rests . Workers were r and omly allocated to a control ( n = 15 ) or test group ( n = 23 ) that used their existing keyboard in a DT system . A post-test was conducted 3 weeks later . Results showed no significant changes in wrist posture , seated posture or reports of musculoskeletal discomfort for the control group , and approximately 50 % of typing wrist movements put the h and in a neutral zone . There were significant improvements in wrist posture , seated posture and upper body musculoskeletal discomfort for the test group using the DT system . Over 80 % of typing wrist movements put the h and into a neutral zone with the DT arrangement . Reactions to using a conventional keyboard on a DT system were positive
Levels of evidence for interventions associated with positive effects were : Moderate evidence for arm supports ; and Limited evidence for ergonomics training plus workstation adjustments , new chair and rest breaks .
Levels of evidence for interventions associated with “ no effect ” were : Strong evidence for workstation adjustment alone ; Moderate evidence for biofeedback training and job stress management training ; and Limited evidence for cognitive behavioral training .
No interventions were associated with “ negative effects ” .
Conclusion It is difficult to make strong evidence d-based recommendations about what practitioners should do to prevent or manage upper extremity MSDs .
There is a paucity of high quality OHS interventions evaluating upper extremity MSDs and none focused on traumatic injury outcomes or workplace m and ated pre-placement screening exams .
Background Little is known about the most effective occupational health and safety ( OHS ) interventions to reduce  upper extremity musculoskeletal disorders ( MSDs ) and injuries .
Methods A systematic review used a best evidence synthesis approach to address the question : “ do occupational health and safety interventions have an effect on upper extremity musculoskeletal symptoms , signs , disorders , injuries , cl aims and lost time ? ”