The comparison of muscle activity according to various conditions during smartphone use in healthy adults

  • Kim, You Lim ;
  • Yoo, Jaehyun ;
  • Kang, Sinwoo ;
  • Kim, Taerim ;
  • Kim, Namyeol ;
  • Hong, Sojeong ;
  • Hwang, Wonjeong ;
  • Lee, Suk Min
  • Received : 2016.02.01
  • Accepted : 2016.03.17
  • Published : 2016.03.30


Objective: The purpose of this study was to see the changes in muscle activity of the upper limb in persons using a smartphone. Design: Cross-sectional study. Methods: An experiment was conducted to target 15 right-handed university students. Experiments were carried out for students using cell phones for more than a year. In this study, experiments were carried out with one-handed and both handed operation of smartphone use in a sitting position, the same parameters with smartphone use in a standing position. The experiments were carried out by having the subjects write a text message in Korean on the smartphone for 3 minutes repeated 3 times with a rest period of 10 seconds given between each 3 minute period. Electromyography (EMG) was used to record the muscle activity of the upper trapezius (UT), extensor carpi radialis (ECR), and abductor pollicis (AP) during phone operation. Results: The muscle activity of the AP and ECR were significantly higher during single handed compared to double handed in both sitting and standing position (p<0.05). The muscle activity of the ECR was significantly higher in standing position compared to sitting position with double handed use of the smartphone (p<0.05). UT muscle activity of the right has been activated more than twice compared to the left UT in a sitting position (p<0.05). And UT muscle activity on the right has been activated more than five times compared to the left in a standing position (p<0.05). Conclusions: Using smartphone with double hand is useful for the prevention of musculoskeletal disorders.


Electromyography;Muscle activation;Smartphone


  1. Kim YM, Yoo HS, Joo YJ Choi SH, Wang JW. A study on the use pattern of Korean mobile phone. National Radio Research Agency (RRA), Ministry of Science ICT and Future Planning. Gwacheon: KCC; 2006.
  2. Korea Communications Commission (KCC), Ministry of Science ICT and Future Planning. Cellphone members statistics. Gwacheon: KCC; 2015.
  3. Yun SH, Min GM, Park DG, Choi YL, Yun SP, Hong SG. Study on the Evaluation of the age of the character input method. J Ergon Soc Korea 2006;10:406-9.
  4. Ryu TB. Performance analysis of text entry with preferred one hand using smart phone touch-keyboard. J Ergon Soc Korea 2011;30:259-64.
  5. Kim CM, Park JH, Kim KH, Oh TO, Son K. Evaluation repetitive strain risk for the thumb joint according to texting types of mobile phones. Korean Soc Precis Eng 2011;11:1477-8.
  6. Park JS. The variables in influencing on smart phone addiction in adolescents and college students [MS thesis]. Yongin: Dankook University; 2011.
  7. Zhang YF, Bang MY. Analysis of variables influencing on the addiction tendencies of chinese high school students at-risk for smartphone addiction. J Spec Child Edu 2014;16:209-26.
  8. Lee MS. Smartphone addiction and related social concerns [MS thesis]. Seoul: Yonsei University; 2011.
  9. Eom SH, Choi SY, Park DH. An empirical study on relationship between symptoms of musculoskeletal disorders and amount of smartphone usage. J Korean Saf Manage Sci 2013;15:113-20.
  10. Xie Y, Szeto GP, Dai J, Madeleine P. A comparison of muscle activity in using touchscreen smartphone among young people with and without chronic neck-shoulder pain. Ergonomics 2016;59:61-72.
  11. Lee HK. The comparison of posture in the use of smartphone on muscle fatigue of cervical erector spinae and upper trapezius in healthy adults [MS thesis]. Seongnam: Gachon University; 2014.
  12. Ong FR. Thumb motion and typing forces during text messaging on a mobile phone. Paper presented at: 13th International Conference on Biomedical Engineering; 2008 Dec 3-6; Singapore. p. 2095-8.
  13. Kim GH, Park JH, Son G. Dynamic modeling of thumb acting on smartphone. J Korean Soc Precis Eng 2012;5 Suppl:1207-8.
  14. Karlson AK. Interface design for sing-handed use of small device. Paper presented at: UIST Adjunct Proceedings Doctoral Symposium; 2006 Oct 15-18; Montreux, Switzerland. p. 27-30.
  15. Berolo S, Wells RP, Amick BC 3rd. Musculoskeletal symptoms among mobile hand-held device users and their relationship to device use: a preliminary study in a Canadian university population. Appl Ergon 2011;42:371-8.
  16. Lee M, Hong Y, Lee S, Won J, Yang J, Park S, et al. The effects of smartphone use on upper extremity muscle activity and pain threshold. J Phys Ther Sci 2015;27:1743-5.
  17. Kim KS, Lee SW, Choi Y, Jin MR. Carpal tunnel syndrome among service and manufacturing workers with repetitive motion tasks. Korean J Occup Environ Med 1998;10:505-23.
  18. Keun YC. A study on the reliability of EMG examination using EM2. Taehan Chikkwa Uisa Hyophoe Chi 1989;27:149-54.
  19. Kamei K. The reliability and validity of surface electromyography to study the functional status of the lumbar paraspinal muscles [MS thesis]. Melbourne: RMIT University; 2008.
  20. Geisser ME, Ranavaya M, Haig AJ, Roth RS, Zucker R, Ambroz C, et al. A meta-analytic review of surface electromyography among persons with low back pain and normal, healthy controls. J Pain 2005;6:711-26.
  21. Kim CM, Park JH, Kim GH, Son K. A comparative evaluation about force and fatigue on thumb according to input type for repetitive use of mobile phone. J Biomed Eng Res 2011;32:312-8.
  22. Kasman G, Wolf S. Surface EMG made easy: a beginner's guide for rehabilitation clinicians. Scottsdale (AZ): Noraxon USA, Inc.; 2002.
  23. von Tscharner V, Barandun M, Stirling LM. Fatigue-related decrease in Piper rhythm frequency of the abductor pollicis brevis muscle during isometric contractions. J Electromyogr Kinesiol 2011;21:190-5.
  24. Kim DS. Biomechanical analysis of a smart phone task with different posture [MS thesis]. Daegu: Kyungbuk National University; 2011.
  25. Koo SJ. Effect of the duration of use of smart phones on forward head posture and muscle fatigue and pain [MS thesis]. Changwon: Kyungnam University; 2015.

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