Wrist postures in video display terminal operators (VDT) using different keyboards

Area of Science:

• Ergonomics
• Occupational Health
• Biomechanics

Background:

• Repetitive strain injuries are common among video display terminal (VDT) workers.
• Keyboard design significantly influences wrist posture and potential for injury.
• Standard QWERTY keyboards may not optimize ergonomic conditions for all users.

Purpose of the Study:

• To compare wrist motion differences between a standard QWERTY keyboard and two alternative ergonomic designs: the Truform and Comfort keyboards.
• To evaluate the impact of keyboard design on wrist flexion-extension and radial-ulnar deviation.
• To identify keyboard designs that promote a more neutral wrist posture.

Main Methods:

• Twenty adult VDT workers participated in a randomized crossover study.
• Participants typed on three keyboards: standard QWERTY, Truform, and Comfort.
• Wrist motion (flexion-extension, radial-ulnar deviation) was measured using the WristSystem during 5-minute typing sessions.
• Contrast score analysis compared mean wrist motion values across keyboard conditions.

Main Results:

• Both Truform and Comfort keyboards significantly reduced ulnar deviation and extension compared to the QWERTY keyboard.
• The Comfort keyboard demonstrated the greatest reduction in ulnar deviation and extension, keeping values within the neutral range.
• The Truform keyboard reduced ulnar deviation but resulted in extension values comparable to or exceeding the QWERTY keyboard.
• Slight increases in radial deviation and flexion were observed with alternative keyboards but remained within neutral zones.

Conclusions:

• The Comfort keyboard is most effective in maintaining a neutral wrist posture among the tested designs.
• Ergonomic keyboards, particularly the Comfort design, can significantly reduce harmful wrist motions.
• Findings can inform occupational therapists in recommending ergonomic keyboard solutions for workstation modifications.