European Journal of Applied Physiology

, Volume 114, Issue 12, pp 2469–2482 | Cite as

Fatigue development in the finger flexor muscle differs between keyboard and mouse use

  • Jeong Ho KimEmail author
  • Peter W. Johnson
Original Article



The aim of the present study was to determine whether there were any physiological changes in the muscle as a result of intensive computer use.


Using a repeated measures experimental design, eighteen subjects participated in four different 8-h conditions: a control (no exposure) condition and three exposure conditions comprised of 6 h of computer use (keyboard, mouse, and combined keyboard and mouse use) followed by 2 h of recovery. In each condition, using 2 Hz neuromuscular electrical stimulation, eight temporal measurements were collected to evaluate the fatigue state (twitch force, contraction time, and ½ relaxation time) of the right middle finger Flexor Digitorum Superficialis (FDS) muscle before, during, and after computer use.


The results indicated that 6 h of keyboard, mouse, and combined mouse and keyboard use all caused temporal fatigue-related changes in physiological state of the FDS muscle. Keyboard use resulted in muscle potentiation, which was characterized by approximately 30 % increase in twitch force (p < 0.0001) and 3 % decrease (p = 0.04) in twitch durations. Mouse use resulted in a combined state of potentiation and fatigue, which was characterized by an increase in twitch forces (p = 0.002) but a prolonging (11 %) rather than a shortening of twitch durations (p < 0.0001).


When comparing mouse and keyboard use, the more substantial change in the physiological state of the muscle with mouse use (potentiation and fatigue compared to just potentiation with keyboard use) provides some physiological evidence which may explain why mouse use has a greater association with computer-related injuries.


Electrical stimulation Muscle fatigue Computer use Musculoskeletal disorders 



This study was supported by the National Institute for Occupational Safety and Health under an R21 Grant (OH009088-02) and Washington State Medical Aid and Accident Fund. The authors would like to thank all the participants for taking part in this study.

Conflict of interest

No conflicts of interest, financial or otherwise, are declared by the authors.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Department of Industrial and Systems EngineeringNorthern Illinois UniversityDeKalbUSA
  2. 2.Department of Environmental and Occupational Health SciencesUniversity of WashingtonSeattleUSA

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