Effects of physical and mental task demands on cervical and upper limb muscle activity and physiological responses during computer tasks and recovery periods

  • Yuling Wang
  • Grace P. Y. Szeto
  • Chetwyn C. H. Chan
Original Article
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Abstract

The present study examined the effects of physical and mental workload during computer tasks on muscle activity and physiological measures. Activity in cervical postural muscles and distal forearm muscles, heart rate and blood pressure were compared among three tasks and rest periods of 15 min each in an experimental study design. Fourteen healthy pain-free adults participated (7 males, mean age = 23.2 ± 3.0 years) and the tasks were: (1) copy-typing (“typing”), (2) typing at progressively faster speed (“pacing”), (3) mental arithmetic plus fast typing (“subtraction”). Typing task was performed first, followed by the other two tasks in a random order. Median muscle activity (50th percentile) was examined in 5-min intervals during each task and each rest period, and statistically significant differences in the “time” factor (within task) and time × task factors was found in bilateral cervical erector spinae and upper trapezius muscles. In contrast, distal forearm muscle activity did not show any significant differences among three tasks. All muscles showed reduced activity to about the baseline level within first 5 min of the rest periods. Heart rate and blood pressure showed significant differences during tasks compared to baseline, and diastolic pressure was significantly higher in the subtraction than pacing task. The results suggest that cervical postural muscles had higher reactivity than forearm muscles to high mental workload tasks, and cervical muscles were also more reactive to tasks with high physical demand compared to high mental workload. Heart rate and blood pressure seemed to respond similarly to high physical and mental workloads.

Keywords

Mental stress Physical stress Electromyography Heart rate Blood pressure 
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Notes

Acknowledgments

The authors would like to acknowledge the Department of Rehabilitation Sciences, The Hong Kong Polytechnic University for funding this project. We would also like to express our appreciation to Dr. Raymond Chung for advice on statistical analysis and Mr. Man Cheung for technical support.

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Yuling Wang
    • 1
    • 3
  • Grace P. Y. Szeto
    • 1
  • Chetwyn C. H. Chan
    • 1
    • 2
  1. 1.Department of Rehabilitation SciencesThe Hong Kong Polytechnic UniversityHong Kong SARChina
  2. 2.Applied Cognitive Neuroscience LaboratoryThe Hong Kong Polytechnic UniversityHong Kong SARChina
  3. 3.Department of Rehabilitation MedicineThe First Affiliated Hospital of Sun Yat-sen UniversityGuangzhouChina

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