How Entirely Split Keyboards Can Impact Wrist Posture

The characteristics of a split keyboard can in principle be modified to affect the posture and comfort of the user is shown in the figure below. The distance of the split, opening angle (γ), fore/aft angle (α), and tenting angle (β) all have a direct impact on level of wrist extension, ulnar deviation, and pronation required to position the hands on the keys.

The ability to adjust these parameters allows an employee to adopt the keyboard to their stature and task, whereas a non-adjustable keyboard will generally require the employee to adopt their body to the equipment.

An important finding of Tittiranonda et al. is that the actual keyboard design and
implementation of ergonomic features makes a big difference in its effectiveness. So someone can own a highly adjustable keyboard but without an understanding of how to implement it, it can be a quite ineffective tool.

So do people of various heights note a positive effect of using an adjustable split keyboard and do people optimize the position of the keyboard to achieve a positive effect when they have one?

The fully split keyboard was shown to have positive results related to posture, discomfort, and performance for all sizes and shapes of people. Ulnar deviation and wrist pronation, awkward wrist postures, was significantly improved. Participants did tent to change their keyboard configurations naturally properly and dramatically different from a conventional keyboard.

The study also explains that people who gave the unconventional fully split keyboards “a solid chance” by not immediately rejecting it when first adapting to it thought the design was much better and would not return to a conventional keyboard. The average keys per minute was not effected by the split design of the keyboard after about a week for a transition period.

The greater the body mass index of the individual resulted in a correlation with the average split angle and distance. This makes sense as individuals with wider shoulders or mid-sections would have wider shoulders resulting in greater ulnar deviation if they were to rest their hands in front of a standard keyboard and align their fingers with the keys.

The study also explains that decreases in discomfort can be seen across the body including but not limited to the neck, and upper back. Splitting the keyboard apart allowed users to reposition their upper extremity and change how they reached for the keyboard. The kinetic chain of muscles from the wrists impacts more than just the wrists.