| Carpal tunnel syndrome (CTS) has been the subject of a growing number of studies, most of them leading to contradictory outcomes. The objective of the thesis was to assess the relationship between various task and device designs used while performing office and industrial work and risk factors for upper extremity musculoskeletal disorders with an emphasis on Carpal Tunnel Syndrome.; Different sections of the thesis looked into different aspects as follows: the forearm muscles activity in different wrist deviated positions and neutral zone, and the self-selected resting position without visual feedback; the effect of different keyboards designs and typing training on wrist motion, overall applied force, forearm muscle activity and typing performance; the effect of wrist/forearm/elbow posture on grip strength; and, the impact of office job design on body and upper extremity musculoskeletal symptoms.; A total of over two hundred and fifty volunteers participated for the five studies. Self selected wrist neutral posture significantly decreased muscle activity. Placement of wrists in neutral zone is expected to reduce risk of injuries. Also, taking into account that the alternative keyboards and training promoted reduced wrist deviation without increasing the EMG activity or reducing the performance, they were considered to constitute valid solutions for conventional keyboard replacement. Awkward postures caused decreased grip force and increased forearm muscles' activity.; The ergonomic assessment of new devices should precede their introduction and not follow it. It is proposed that a thorough understanding of the factors that intervene in the task-CTS causal relationship, as well as the assessment of workers' adaptation capacity will lead to ergonomic interventions that may reduce the number of work-related CTS cases. |
