Scientific/Clinical Article| Volume 31, ISSUE 1, P42-51, January 2018

Hand rest and wrist support are effective in preventing fatigue during prolonged typing

Published:February 21, 2017DOI:


      Study Design

      Case series (longitudinal).


      Only few reports concerning the efficacy of commonly used strategies for preventing upper limb occupational disorders associated with prolonged typing exist.

      Purpose of the Study

      We aimed to investigate whether the duration of typing and the use of 2 strategies (hand rest and wrist support) changes muscle physiological response and therefore the electromyography records.


      We enrolled 25 volunteers, who were unfamiliar with the task and did not have musculoskeletal disorders. The subjects underwent 3 prolonged typing protocols to investigate the efficacy of the 2 adopted strategies in reducing the trapezius, biceps brachii, and extensor digitorum communis fatigue.


      Typing for 1 hour induced muscular fatigue (60%-67% of the subjects). The extensor digitorum communis muscle exhibited the highest percentage of fatigue (72%-84%) after 1 and 4 hours of typing (1 hour, P = .04; 4 hours, P = .02). Fatigue levels in this muscle were significantly reduced (24%) with the use of pause typing (4 hours, P = .045), whereas biceps brachii muscle fatigue was reduced (32%) only with the use of wrist supports (P = .02, after 4 hours). Trapezius muscle fatigue was unaffected by the tested occupational strategies (1 hour, P = .62; 4 hours, P = .85).


      Despite presenting an overall tendency for fatigue detected during the application of the protocols, the assessed muscles exhibited different behavior patterns, depending on both the preventive strategy applied and the muscle mechanical role during the task.


      Hand rest and wrist support can successfully reduce muscle fatigue in specific upper limb muscles during prolonged typing, leading to a muscle-selective reduction in the occurrence of fatigue and thus provide direct evidence that they may prevent work-related musculoskeletal disorders.

      Level of Evidence



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      JHT Read for Credit

      Quiz: #523

      Record your answers on the Return Answer Form found on the tear-out coupon at the back of this issue or to complete online and use a credit card, go to There is only one best answer for each question.
      • #1.
        The study design was
        • a.
        • b.
        • c.
          a retrospective cohort
        • d.
          a longitudinal case series
      • #2.
        The proposed intervention was a combination of
        • a.
          ultrasound and deep friction massage
        • b.
          splinting and resistive exercise
        • c.
          wrist support and rest
        • d.
          rest from function and TENS
      • #3.
        The subject population was
        • a.
          all normal volunteers
        • b.
          all patients with chronic fatigue syndrome
        • c.
          50% normal and 50% actual patients
        • d.
          professional soccer players
      • #4.
        The muscle exhibiting the most fatigue was the
        • a.
        • b.
        • c.
        • d.
      • #5.
        The proposed intervention demonstrated positive effects
        • a.
        • b.
      When submitting to the HTCC for re-certification, please batch your JHT RFC certificates in groups of 3 or more to get full credit.