Keyboard design through physiological strain measurements

Muscular load and performance compared between a pen and a computer mouse as input devices

“…Similar results were found by all aforementioned studies, including ours. These findings seem contradictory to Zipp et al (1983). An explanation was published recently by Brown et al (2007).…”

“…According to the manufacturer of the I-pen, the more natural hand position during use of the I-pen should reduce the muscular load on the Trapezius. Zipp et al (1983) investigated the effects of lower arm pronation on Trapezius EMG. Their results showed that a pronation of the lower arm reduced by 10 already caused significantly lower muscle activity in neck, shoulder and arm muscles during keyboard work.…”

The effect of six keyboard designs on wrist and forearm postures

“…The evidence linking awkward wrist and forearm postures during keyboard use to elevated risk for arm disorders is mixed (Gerr et al, 2004). However, during the past 50 years, a number of alternative geometry keyboard designs have been proposed to reduce awkward wrist and forearm postures during typing (Kroemer, 1972;Zipp et al, 1983;Nakaseko et al, 1985;Honan et al, 1995). Only recently has there been evidence, from prospective intervention trials, that alternative geometry keyboard designs may reduce or prevent hand and arm pain and disorders (Tittiranonda et al, 1999;Moore and Swanson, 2003).…”

Workplace Use of an Adjustable Keyboard: Adjustment Preferences and Effect on Wrist Posture

“…(13,14) Electromyographic studies conducted on split keyboard users also showed reduced electrical activities of the forearm as well as the neck and shoulder muscles. (15,16) In response to these findings, alternative keyboards have been designed and marketed to improve hand and forearm postures as well as comfort during typing. Performance, electromyographic analysis, and subjective preference data, based on short-term (1-3 day) use of these keyboards have demonstrated decreased electromyographic activities of the finger flexors and extensors and wrist flexors, (17) significant reduction in wrist extension and ulnar deviation, (18,19) and favorable ratings (20,21) in comparison with a conventional keyboard.…”