The present study aims to evaluate the effects of posture, task, and handgrip style on discomfort, neck kinematics, and concomitant muscular activity when using a smartphone (SP).
Background
Along with the popularity of smartphones, musculoskeletal disorders have become prevalent among smartphone users. However, comprehensive aspects of discomfort, kinematics, and electromyographic responses across various conditions remain to be investigated.
Method
Twenty-four young smartphone users performed typing, video watching, and reading tasks while holding the smartphone both with one hand and with two hands while either sitting or standing. Neck kinematics and muscular activities were simultaneously recorded.
Results
Working with SPs led to higher discomfort in the neck (p = 0.01), lower back (p = 0.01), and shoulder (p = 0.04) while sitting as compared to standing. Sitting was associated with greater neck flexion and more minor lateral bending for all tasks and grip styles (p < 0.05). Electromyographic analysis indicated significant differences between sitting and standing, with alterations being dependent on the test condition. Moreover, neck kinematics and muscular activities significantly differed based on the task nature, handgrip, and interactions.
Conclusion
This study highlights the risk of using smartphones in increased neck angle flexion and muscular activities fatigue. Thus, posture and handgrip should be considered while using SPs. As each test condition affects a specific dependent variable, a holistic approach is required to evaluate the responses of SP users’ musculoskeletal systems.
Application
Results can be applied to develop guidelines for musculoskeletal disorders/discomfort prevention among SP users, especially with the rise of smartphone use during the COVID-19 pandemic.
AkkayaN.DoguB.ÜnlüZ.ÇarlA. B.AkkayaS.TekinL.ÖzçakarL. (2015). Ultrasonographic evaluation of the flexor pollicis longus tendon in frequent mobile phone texters. American Journal of Physical Medicine & Rehabilitation, 94, 444–448. https://doi.org/10.1097/PHM.0000000000000186
2.
AntonaB.BarrioA. R.GascoA.PinarA.Gonzalez-PerezM.PuellM. C. (2018). Symptoms associated with reading from a smartphone in conditions of light and dark. Applied Ergonomics, 68, 12–17. https://doi.org/10.1016/j.apergo.2017.10.014
3.
AsakawaD. S.DennerleinJ. T.JindrichD. L. (2017). Index finger and thumb kinematics and performance measurements for common touchscreen gestures. Applied Ergonomics, 58(9), 176–181. https://doi.org/10.1016/j.apergo.2016.06.004
4.
BeroloS.WellsR. P.AmickB. C.III (2011). Musculoskeletal symptoms among mobile hand-held device users and their relationship to device use: A preliminary study in a Canadian university population. Applied Ergonomics, 42(2), 371–378. https://doi.org/10.1016/j.apergo.2010.08.010
5.
ChoiJ.-H.JungM.-H.YooK.-T. (2016). An analysis of the activity and muscle fatigue of the muscles around the neck under the three most frequent postures while using a smartphone. Journal of Physical Therapy Science, 28(5), 1660–1664. https://doi.org/10.1589/jpts.28.1660
6.
CosciaM.CheungV. C.TropeaP.KoenigA.MonacoV.BennisC. (2014). The effect of arm weight support on upper limb muscle synergies during reaching movements. Journal of Neuroengineering and Rehabilitation, 11, 1–15. https://doi.org/10.1186/1743-0003-11-22
7.
Factors, A. N. S. I. H., & Society, E. (2007). ANSI/HFES 100–2007 human factors engineering of computer workstations. Hum Fact Ergon Soc, 10, 89.
GoldJ. E.DribanJ.ThomasN.ChakravartyT.ChannellV.KomaroffE.-G. (2012). Postures, typing strategies, and gender differences in mobile device usage: An observational study. Applied Ergonomics, 43(2), 408–412. https://doi.org/10.1016/j.apergo.2011.06.015
10.
GonçalvesJ. S.MoriguchiC. S.TakekawaK. S.CouryH. J. C. G.de Oliveira SatoT. (2017). The effects of forearm support and shoulder posture on upper trapezius and anterior deltoid activity. Journal of Physical Therapy Science, 29(5), 793-798. https://doi.org/10.1589/jpts.29.793
GustafssonE.CoenenP.CampbellA.StrakerL. (2018). Texting with touchscreen and keypad phones-A comparison of thumb kinematics, upper limb muscle activity, exertion, discomfort, and performance. Applied Ergonomics, 70, 232–239. https://doi.org/10.1016/j.apergo.2018.03.003
13.
GustafssonE.JohnsonP. W.HagbergM. (2010). Thumb postures and physical loads during mobile phone use–A comparison of young adults with and without musculoskeletal symptoms. Journal of Electromyography and Kinesiology, 20(1), 127–135. https://doi.org/10.1016/j.jelekin.2008.11.010
14.
GustafssonE.ThoméeS.Grimby-EkmanA.HagbergM. (2017). Texting on mobile phones and musculoskeletal disorders in young adults: A five-year cohort study. Applied Ergonomics, 58, 208–214. https://doi.org/10.1016/j.apergo.2016.06.012
15.
HajifarS.SunH.MegahedF. M.Jones-FarmerL. A.RashediE.CavuotoL. A. (2021). A forecasting framework for predicting perceived fatigue: Using time series methods to forecast ratings of perceived exertion with features from wearable sensors. Applied Ergonomics, 90, 103262. https://doi.org/10.1016/j.apergo.2020.103262
HansrajK. K. (2014). Assessment of stresses in the cervical spine caused by posture and position of the head. Surgical Technology International, 25, 277–279.
18.
HermensD.FeriksB. (2005). Surface electromyography for the non-invasive assessment of muscles (seniam). European Union.
19.
Hiemstra-van MastrigtS.KampI.Van VeenS.VinkP.BoschT. (2015). The influence of active seating on car passengers' perceived comfort and activity levels. Applied Ergonomics, 47, 211–219. https://doi.org/10.1016/j.apergo.2014.10.004
20.
IjiriT.UrabeY.MaedaN.SasadaiJ.SuzukiT. (2020). Comparative study of the differences in shoulder muscle activation according to arm rotation angle. Human Movement Science, 69, 102567. https://doi.org/10.1016/j.humov.2019.102567
21.
KazemiZ.MazloumiA.ArjmandN.KeihaniA.KarimiZ.GhasemiM. S., (2021). A comprehensive evaluation of spine kinematics, kinetics, and trunk muscle activities during fatigue-induced repetitive lifting. Human Factors, 1–16.
22.
KietrysD. M.GergM. J.DropkinJ.GoldJ. E. (2015). Mobile input device type, texting style and screen size influence upper extremity and trapezius muscle activity, and cervical posture while texting. Applied Ergonomics, 50, 98–104. https://doi.org/10.1016/j.apergo.2015.03.003
23.
KimH. K.KimN.ParkJ. (2020). Relationship analysis between body flexion angles and smartphone tilt during smartphone use. International Journal of Industrial Ergonomics, 80(3), 103034. https://doi.org/10.1016/j.ergon.2020.103034
24.
KimM.-S. (2015). Influence of neck pain on cervical movement in the sagittal plane during smartphone use. Journal of Physical Therapy Science, 27(1), 15–17. https://doi.org/10.1589/jpts.27.15
25.
KimT. (2016). Effect of duration of smartphone use on muscle fatigue and pain caused by forward head posture in adults. Journal of Physical Therapy Science, 28(6), 1669–1672. https://doi.org/10.1589/jpts.28.1669
26.
KoP.-H.HwangY.-H.LiangH.-W. (2016). Influence of smartphone use styles on typing performance and biomechanical exposure. Ergonomics, 59(6), 821–828. https://doi.org/10.1080/00140139.2015.1088075
27.
KonradP. (2005). The abc of emg. A Practical Introduction to Kinesiological Electromyography, 1, 30–35.
28.
LeeM.HongY.LeeS.WonJ.YangJ.ParkS. (2015a). The effects of smartphone use on upper extremity muscle activity and pain threshold. Journal of Physical Therapy Science, 27(6), 1743–1745. https://doi.org/10.1589/jpts.27.1743
LeeT.-H.ChoiJ.-D.LeeN.-G. (2015c). Activation timing patterns of the abdominal and leg muscles during the sit-to-stand movement in individuals with chronic hemiparetic stroke. Journal of Physical Therapy Science, 27(11), 3593–3595. https://doi.org/10.1589/jpts.27.3593
MingZ.PietikainenS.HänninenO. (2006). Excessive texting in pathophysiology of first carpometacarpal joint arthritis. Pathophysiology, 13(4), 269–270. https://doi.org/10.1016/j.pathophys.2006.09.001
33.
NamwongsaS.PuntumetakulR.NeubertM. S.BoucautR. (2019). Effect of neck flexion angles on neck muscle activity among smartphone users with and without neck pain. Ergonomics, 62(12), 1524–1533. https://doi.org/10.1080/00140139.2019.1661525
34.
NingX.HuangY.HuB.NimbarteA. D. (2015). Neck kinematics and muscle activity during mobile device operations. International Journal of Industrial Ergonomics, 48, 10–15. https://doi.org/10.1016/j.ergon.2015.03.003
35.
O’ConnorC. M.ThorpeS. K.O’MalleyM. J.VaughanC. L. (2007). Automatic detection of gait events using kinematic data. Gait & Posture, 25(3), 469–474. https://doi.org/10.1016/j.gaitpost.2006.05.016
36.
SeghersJ.JochemA.SpaepenA. (2003). Posture, muscle activity and muscle fatigue in prolonged VDT work at different screen height settings. Ergonomics, 46(7), 714–730. https://doi.org/10.1080/0014013031000090107
37.
SENIAM (2007). Surface EMG for non-invasive assessment of muscles.
38.
ShinG.ZhuX. (2011). User discomfort, work posture and muscle activity while using a touchscreen in a desktop PC setting. Ergonomics, 54(8), 733–744. https://doi.org/10.1080/00140139.2011.592604
39.
StrakerL. M.ColemanJ.SkossR.MaslenB. A.Burgess-LimerickR.PollockC. M. (2008). A comparison of posture and muscle activity during tablet computer, desktop computer and paper use by young children. Ergonomics, 51(4), 540–555. https://doi.org/10.1080/00140130701711000
40.
SyamalaK. R.AilneniR. C.KimJ. H.HwangJ. (2018). Armrests and back support reduced biomechanical loading in the neck and upper extremities during mobile phone use. Applied Ergonomics, 73, 48–54. https://doi.org/10.1016/j.apergo.2018.06.003
41.
TakalaE.-P. (2002). Static muscular load, an increasing hazard in modern information technology. Scandinavian Journal of Work, 28(4), 211–213. Environment & health. https://doi.org/10.5271/sjweh.667
42.
TegtmeierP. (2018). A scoping review on smart mobile devices and physical strain. Work, 59(2), 273–283. https://doi.org/10.3233/WOR-172678
43.
TohS. H.CoenenP.HowieE. K.StrakerL. M. (2017). The associations of mobile touch screen device use with musculoskeletal symptoms and exposures: A systematic review. Plos One, 12(8), e0181220. https://doi.org/10.1371/journal.pone.0181220
44.
VahediZ.MazloumiA.SharifnezhadA.KazemiZ.GarosiE. (2020). Head forward flexion, lateral bending and viewing distance while using a smartphone: A comparison between sitting and standing postures. Work, 67, 1–10. https://doi.org/10.3233/WOR-203303
VillanuevaM. B. G.JonaiH.SotoyamaM.HisanagaN.TakeuchiY.SaitoS. (1997). Sitting posture and neck and shoulder muscle activities at different screen height settings of the visual display terminal. Industrial Health, 35(3), 330–336. https://doi.org/10.2486/indhealth.35.330
47.
XieY.SzetoG. (2015). A study of muscle activity in using touchscreen smartphone among young people with and without neck-shoulder pain. Physiotherapy, 101, e1668–e1669. https://doi.org/10.1016/j.physio.2015.03.068
48.
XieY.SzetoG. P.DaiJ.MadeleineP. (2016). A comparison of muscle activity in using touchscreen smartphone among young people with and without chronic neck–shoulder pain. Ergonomics, 59(1), 61–72. https://doi.org/10.1080/00140139.2015.1056237
49.
XieY. F.SzetoG.MadeleineP.TsangS. (2018). Spinal kinematics during smartphone texting–A comparison between young adults with and without chronic neck-shoulder pain. Applied Ergonomics, 68, 160–168. https://doi.org/10.1016/j.apergo.2017.10.018
50.
YoonW.ChoiS.HanH.ShinG. (2021). Neck muscular load when using a smartphone while sitting, standing, and walking. Human Factors, 63(5), 868–879. https://doi.org/10.1177/0018720820904237
51.
YoungJ. G.TrudeauM.OdellD.MarinelliK.DennerleinJ. T. (2012). Touch-screen tablet user configurations and case-supported tilt affect head and neck flexion angles. Work, 41(1), 81–91. https://doi.org/10.3233/WOR-2012-1337
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