Journal of Physical Therapy Science
Online ISSN : 2187-5626
Print ISSN : 0915-5287
ISSN-L : 0915-5287
Original Article
The effects of smartphone use on upper extremity muscle activity and pain threshold
Minkyung LeeYunkyung HongSeunghoon LeeJinyoung WonJinjun YangSookyoung ParkKyu-Tae ChangYonggeun Hong
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Keywords: VDT, Smartphone, Muscle pain

2015 Volume 27 Issue 6 Pages 1743-1745


[Purpose] The purpose of this study was to determine whether muscle activity and pressure-induced pain in the upper extremities are affected by smartphone use, and to compare the effects of phone handling with one hand and with both hands. [Subjects] The study subjects were asymptomatic women 20–22 years of age. [Methods] The subjects sat in a chair with their feet on the floor and the elbow flexed, holding a smartphone positioned on the thigh. Subsequently, the subjects typed the Korean anthem for 3 min, one-handed or with both hands. Each subject repeated the task three times, with a 5-min rest period between tasks to minimize fatigue. Electromyography (EMG) was used to record the muscle activity of the upper trapezius (UT), extensor pollicis longus (EPL), and abductor pollicis (AP) during phone operation. We also used a dolorimeter to measure the pressure-induced pain threshold in the UT. [Results] We observed higher muscle activity in the UT, AP, and EPL in one-handed smartphone use than in its two-handed use. The pressure-induced pain threshold of the UT was lower after use of the smartphone, especially after one-handed use. [Conclusion] Our results show that smartphone operation with one hand caused greater UT pain and induced increased upper extremity muscle activity.

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© 2015 by the Society of Physical Therapy Science. Published by IPEC Inc.

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives (by-nc-nd) License.
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