JANET BLACKSTONE
Physical Exposure Differences Between Children and Adults on Different-sized Computer Input Devices
Safety and Ergonomics, MS
Preceptor: Peter Johnson, PhD
Today’s youth start using computers at an earlier age and have longer daily exposures compared to previous generations. People of all ages use standard computer input devices designed for adult males, and because body dimensions and strength vary widely, children using standard computer equipment may have a greater tendency to experience awkward postures or apply excessive forces during computer work. Reports in the scientific literature suggest that soft tissue injuries are not uncommon in adults who use computers, and self-reporting of discomfort attributed to computer use among school-age children has recently been documented.
The primary aims of this study were i) to characterize the relevant anthropometry of adults and children and ii) to measure the physical exposures of wrist posture, muscle activity, and force expended as a percent of maximal capacity in children and their same-gender biological parents using a standard-sized and smaller keyboard and mouse.
Children worked with two to three times the range of motion of the adults on the standard mouse and keyboard, respectively, and worked with greater ulnar deviation and less extension than the adults. Adults worked at higher muscular loads while typing with a 10-fold difference in typing productivity, compared to children. Device size influenced both wrist posture and muscular load in children: they operated the small mouse with less ulnar deviation and lower muscular activity compared to the standard mouse. Adults had greater wrist extension on the small mouse compared to the standard.
These physical exposure differences may portend adverse symptom development, thus calling into question the appropriateness of children using adult-sized computer input devices. The findings of this study may have applications in the design of size-appropriate computer input devices for children.
