Comparing learning during the familiarization phase with a slanted mouse and a vertical mouse when performing a repeated pointing-clicking task.

Purpose. Vertical and slanted mouse models have been developed to reduce forearm pronation. Discomfort, performance and stresses have been analyzed with these mice in previous studies but not learning during the familiarization phase. Methods. Eighteen females performed repeated pointing-clicking tasks with a standard mouse used as a reference followed by a slanted mouse and a vertical mouse in a randomized order. The duration of each task was measured. For each participant-mouse combination, changes in duration upon repeating the task were analyzed using a statistical model including a log-linear slope followed by a plateau. We consider that when the plateau is reached, the participant is familiar with the task. Results. For both the slanted mouse and the vertical mouse, the plateau is reached after about 30 repetitions of the task. The duration of the plateau was similar for these two mouse models. For the vertical mouse only, the slope increased significantly when used second versus when used first. Conclusion. Learning speed appeared slower with the vertical mouse than with the slanted mouse. In light of these findings and those of previous studies, decision-makers and employees should consider the slanted mouse rather than the vertical mouse.

Effects of mouse slant and desktop position on muscular and postural stresses, subject preference and performance in women aged 18-40 years.

This study compared muscular and postural stresses, performance and subject preference in women aged 18-40 years using a standard mouse, a vertical mouse and a slanted mouse in three different computer workstation positions. Four tasks were analysed: pointing, pointing-clicking, pointing-clicking-dragging and grasping-pointing the mouse after typing. Flexor digitorum superficialis (FDS) and extensor carpi radialis (ECR) activities were greater using the standard mouse compared to the vertical or slanted mouse. In all cases, the wrist position remained in the comfort zone recommended by standard ISO 11228-3. The vertical mouse was less comfortable and more difficult to use than the other two mice. FDS and ECR activities, shoulder abduction and wrist extension were greater when the mouse was placed next to the keyboard. Performance and subject preference were better with the unrestricted mouse positioning on the desktop. Grasping the mouse after typing was the task that caused the greatest stress. Practitioner Summary: In women, the slanted mouse and the unrestricted mouse positioning on the desktop provide a good blend of stresses, performance and preference. Unrestricted mouse positioning requires no keyboard, which is rare in practice. Placing the mouse in front of the keyboard, rather than next to it, reduced the physical load.

Incidence of Stress and Psychosocial Factors on Musculoskeletal Disorders in CAD and Data Entry.

A comparative study concerning the incidence of psychosocial factors and stress on musculoskeletal disorders (MSD) was conducted on 30 males carrying out a computer-aided design (CAD) task and on 26 females carrying out a data entry task. Both populations completed a questionnaire concerning complaints of MSD, stress symptoms, psychosocial factors and working life. This study showed that the work context was more favourable to the data entry task operators than to the CAD task operators. In addition, there were relationships in CAD and in data entry between complaints of MSD and stress variables as well as between anguish and psychosocial factors. This field study has shown the importance of stress and of the work context in the occurrence of MSD in computer work.

Biomechanical stresses in computer-aided design and in data entry.

A study of the risk factors of musculoskeletal disorders (MSDs) of the upper limbs was carried out on 2 populations, 1 performing a computer-aided design (CAD) task and the other performing a data entry task. A questionnaire on MSD complaints and working life was completed by a sample of each population. Biomechanical measurements of the forces, the angles, and the repetitiveness of movements of the upper limbs were carried out on some operators in each sample. It emerged that complaints of the upper limbs seem to be linked to the use of input devices. The grip forces exerted when using the keyboard and mouse were higher in CAD than in data entry.