Biomechanics and performance when using a standard and a vertical computer mouse

The use of computer mouse devices started in the 1980s because of graphic design media needs. Since then, it became a standard tool for user–computer interface and interaction. However, the standard computer mouse design requires upper extremity postures that may increase carpal tunnel pressure and median nerve strain, decrease blood flow and result in muscle fatigue, all of which are associated with carpal tunnel syndrome (CTS) and other upper extremity MSD.

The vertical mouse (VM) is an alternative to the standard mouse (SM) because it has a different design that intends to minimise some of the problems previously identified with the standard computer mouse. The authors’ objective behind doing this study was to compare the upper limb biomechanics and task performance when using a standard and a vertical computer mouse (VM).

They measured the muscle activation (electromyography), forearm movements (electrogoniometers), performance (Fitts’ Law test) and satisfaction (questionnaire) of 16 subjects.

There were significant differences between the VM and the SM, respectively, on motion (288 vs. 428 pronation, p ¼ 0.001; 58 ulnar vs. 78 radial deviation, p ¼ 0.016) and muscle activity (13% vs. 16% of extensor carpi activity, p ¼ 0.006; 10% vs. 13% extensor digitorum activity, p ¼ 0.001). VM user satisfaction was good (68); however, time to target was longer (4.2 vs. 3.4 s, p, 0.001).

The authors’ concluded that using the VM decreased wrist pronation and lowered wrist extensor muscle activity, but additional training and familiarisation time may be required to improve user performance.