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Table of Contents
ORIGINAL ARTICLE
Year : 2020  |  Volume : 2  |  Issue : 2  |  Page : 92-98

A study on the relationship between median nerve mobility and cervical core muscle endurance among asymptomatic young adults using smartphone


Physiotherapy Department, PT School and Center, TNMC and BYL Nair Hospital, Mumbai, Maharashtra, India

Date of Submission06-Apr-2020
Date of Decision04-Jun-2020
Date of Acceptance10-Sep-2020
Date of Web Publication04-Jan-2021

Correspondence Address:
Dr. Danielle Malcolm Dsouza
B504, Sarla Garden, Nehru Road, Vakola, Santacruz East, Mumbai 400 055, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijptr.ijptr_10_20

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  Abstract 


Background and Objectives: The posture adopted when using a smartphone is a major cause for concern. The objective of the study was to find the correlation of neural tissue mobility of the median nerve and cervical core muscle endurance with smartphone use in asymptomatic young adults.
Materials and Methods: This was a cross-sectional observational study conducted in a tertiary care hospital. A total of 75 asymptomatic young adults were assessed for the frequency and intensity of smartphone use, cervical core muscle endurance, and neural tissue mobility of the median nerve.
Statistical Analysis Used: Spearman correlation test was used in this study.
Results: The study showed a significant correlation of median nerve mobility with the Problematic Mobile Phone Use (PUMP) Scale score (P = 0.00, r[dominant], r[nondominant] =0.588) and the duration of smartphone use. In terms of number of years, r (dominant) =0.516, r (nondominant) = 0.413. In terms of number of hours/day, r (dominant) = 0.776, r (nondominant) = 0.597. Furthermore, a significant correlation of cervical core muscle endurance with the PUMP Scale score [P = 0.00, r = −0.730] and duration of smartphone use exists. In terms of number of years, P = 0.00, r = −0.534. In terms of number of hours, P = 0.00, r = −0.791.
Conclusion: The neural tissue mobility of the median nerve is hampered with increased smartphone use in terms of duration of use. Furthermore, the cervical core endurance is less in individuals who use their smartphone for longer durations and in those who are more addicted.

Keywords: Asymptomatic young adults, cervical core muscle endurance, median nerve mobility, smartphone


How to cite this article:
Kubal SV, Dsouza DM. A study on the relationship between median nerve mobility and cervical core muscle endurance among asymptomatic young adults using smartphone. Indian J Phys Ther Res 2020;2:92-8

How to cite this URL:
Kubal SV, Dsouza DM. A study on the relationship between median nerve mobility and cervical core muscle endurance among asymptomatic young adults using smartphone. Indian J Phys Ther Res [serial online] 2020 [cited 2021 Jan 15];2:92-8. Available from: https://www.ijptr.org/text.asp?2020/2/2/92/189936




  Introduction Top


Today's smartphones resemble mini-computers making them indispensable gadgets among youngsters. A major cause for concern is that the user is forced to adopt awkward postures which increase neck flexion and extreme wrist positions.[1] According to Junhyuk et al., as the neck flexion angle increases, additional stresses are placed on the ligaments and muscles of the cervical spine.[2] To maintain a correct posture in the cervical region, the deep neck flexors contribute in maintaining a balance between the head and neck. They stabilize the cervical spine using low levels of static muscle endurance instead of generating high levels of mobility.[3] Over a period of time, the altered posture adopted while using the smart phone alters the length-tension relationship of the cervical muscles, decreasing their muscular efficiency and extra muscle action is thus needed to hold the head and neck in a stable position.[4]

Research has shown that the median nerve is responsible for the movements related to smartphone use.[5] The past research has also shown that the nervous system adapts to mechanical loads by undergoing elongation, sliding, cross-sectional change, angulation, and compression in response to physical stresses, failing which it is vulnerable to conditions which may alter the neurodynamics.[6] The combination of increased neck flexion angles, abnormal postures and styles while typing, and repetitive motion of the wrist, thumb, and fingers, without taking adequate breaks, thereby affects the musculoskeletal system and results in fatigue, pain, and repetitive stress injuries.[7]

There is a paucity of literature on the effect of smartphone use on the mobility of the median nerve and the increased neck flexion angles adopted during use on the endurance of the deep neck flexors in young Indian adults who are avid users of the smartphone. Hence, the present study aimed at filling this lacuna.


  Materials and Methods Top


This was a cross-sectional observational study conducted at the Physiotherapy Outpatient Department of B. Y. L. Nair Charitable Hospital, Mumbai. Seventy-five individuals were included in the study by convenience sampling using the formula: N= [(Zα+ Zβ)/C] 2 + 3.[8] In accordance with Jin In Lee et al., the correlation of coefficient® = 0.339 was taken.[9] The study was endorsed by the Institutional Ethics Committee.

The purpose of the study was explained and written, and an audiovisual informed consent was also obtained from the participants. Asymptomatic young adults between 18 and 25 years of age, using the smartphone for at least 1 year, who understood English were included. Individuals undergoing fitness training, with experiences of medical attention for neck/upper extremity, suffering from any inflammatory, degenerative, or neuromuscular condition of the upper extremity/neck affecting the ADLs, with impaired cognitive function, and those involved in activities involving repetitive movements of the upper extremity/neck in the past 6 months were excluded from the study.

Each participant participated in a single testing session and was given a consent form to ensure voluntary participation in the study. Data were obtained from the participants and recorded.

Methodology

Problematic Mobile Phone Use Scale

This scale was used to assess the frequency and intensity of mobile phone usage. The scale comprised 20 items and was self-administered by the participant, and the most suitable option was selected on a Likert scale, “1” indicating “strongly disagree” and “5” indicating “strongly agree.” The total score was obtained by adding the score of each individual item.[10]

Cervical core muscle endurance

The pressure biofeedback unit (folded into thirds) was placed under the upper cervical spine and inflated to a baseline pressure of 20 mmHg

The participant was instructed to nod and increase pressure on the cuff to 22 mmHg and hold the pressure steady for 10 s as shown in [Figure 1]
Figure 1: Technique used to measure the endurance of the deep neck flexors using the pressure biofeedback stabilizer

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If the participant could hold the position with minimal superficial muscle activity, he/she was asked to relax and repeat the flexion, this time increasing the pressure to 24 mmHg. This was incrementally increased by 2 mm up to 30 mmHg

The final pressure was the one at which the participant could hold steady for10 s

Muscle endurance of the deep neck flexors was measured by the number of 10 s holds (up to 10) at the final pressure, with a rest period of 10 s between repetitions. Loss of pressure of > 2 mmHg was regarded as failure, and the number of repetitions to that point was used in the calculation of the holding capacity. A performance index was used to document an objective measure as follows:

Performance Index = Increase in Pressure × Number of repetitions of 10 s holds.[11],[12]

Neural tissue mobility of the median nerve

As shown in [Figure 2]a, [Figure 2]b the participant was in a supine and relaxed position and was instructed to look toward the ceiling. The limb not being tested was kept relaxed on the abdomen while the examiner performed the following movement sequence on the upper extremity being tested.[13],[14]
Figure 2: (a) End position of ULTT1 with ipsilateral cervical flexion. (b) End position of ULTT1 with contralateral cervical flexion

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  1. Scapular depression
  2. Shoulder abduction to 110°
  3. Forearm supination and wrist and finger extension
  4. Elbow extension
  5. Contralateral/ipsilateral cervical side flexion.


Two elbow extension measurements as given below were used to calculate the elbow deficit angle.

Elbow deficit angle = Elbow extension with contra-lateral cervical spine lateral flexion - elbow extension with ipsi-lateral cervical spine lateral.

Statistical analysis

Data were analyzed using the IBM SPSS Software (version 25, SPSS Inc, Chicago, Illinois. U.S). Descriptive analysis of the data was done. As the data did not pass the Shapiro–Wilk test for normality, Spearman's test was used to assess the correlation between the variables (rs).


  Results Top


The present study was conducted in an urban setup on 75 physiotherapy students between the age group of 18 and 25 years, with a mean age of 21.19 ± 1.814 years. Out of the total sample population, 64 (84.3%) were female, while 11 (14.7%) were male, and 71 participants (94.7%) were right-hand dominant, while 4 (5.3%) were left-hand dominant. The participants used the smartphone for a minimum of 1 year and a maximum of 9 years, with a mean of 5.76 ± 2.065 years and 4.4008 ± h/day. Out of the total number of participants, 53 (70.7%) used both hands for texting, while 22 participants (29.3%) used only the dominant hand. The mean neural tissue tightness on the dominant side was 10.52° ± 4.455°, and on the nondominant side, it was 6.92° ± 3.157°. The participants had a mean cervical core endurance of 48.48 ± 16.552, and on a score of 20–100, the mean Problematic Mobile Phone Use (PUMP) Scale score was 52.08 ± 15.013 [Table 1].
Table 1: DESCRIPTIVE STATISTICS

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There was a significant correlation between the Upper Limb Tension Test 1 (ULTT1) and the PUMP Scale score. The “r” values were found to be 0.833 and 0.588 on the dominant and nondominant sides, respectively [Graph 1](a) and [Graph 2](a)]. Furthermore, there was a significant correlation between the ULTT1 and the duration of smartphone use. In terms of number of years, the “r” values were found to be 0.516 and 0.413 on the dominant and nondominant sides, respectively [Graph 1](b) and [Graph 2](b)]. In terms of number of hours, the “r” values were found to be 0.776 and 0.598 on the dominant and nondominant sides, respectively [Graph 1](c) and [Graph 2](c)].



There was a significant correlation between the cervical core muscle endurance and the PUMP Scale score. The “r” value was found to be − 0.730 [Graph 3](a)]. There was a significant correlation between the cervical core muscle endurance and the duration of smartphone use. In terms of number of years of use, the “r” value was found to be − 0.534 [Graph 3](b)]. In terms of number of hours of use per day, the “r” value was found to be −0.791 [Graph 3](c)].




  Discussion Top


The present study aimed at correlating the effect of smartphone use with endurance of the cervical core muscles as well as with the neural tissue mobility of the median nerve.

A strong correlation between the neural tissue tightness of the median nerve and the smartphone addiction on the PUMP Scale on the dominant side, while only a moderate correlation on the nondominant side implies that an increased addiction to the smartphone hampers the mobility of the median nerve, thereby producing tightness of the neural tissue, which has more effect on the dominant side as compared to the nondominant side.

Furthermore, the current study showed a positive correlation between the ULTT1 and the duration of smartphone use, implying that an increased duration of use increases the neural tissue tightness.

According to Shahanawaz, in static postures, the segments of the body are aligned and maintained in certain positions, increasing the passive tension on the neural tissue. This, in turn, may alter the physical stresses on the nerve trunk resulting in altered compression or elongation of the nerve.[15] The results of this study are supported by Alruzayhi et al. who concluded that increased duration of smartphone use increases its negative effects on the nerves and other soft-tissue structures in the upper quadrant.[16] Furthermore, Inal et al. indicated the possibility of enlargement of the median nerve in high smartphone users who have a habit of single-handheld smartphone use.[17] Furthermore, a study by Andrea Julius et al. found that shoulder protraction does restrict median nerve sliding resulting in paresthesia in the median nerve distribution.[18] Furthermore, altered postures attained during prolonged smartphone use can cause some muscles to be placed in shortened positions, over time resulting in increased compression on the nerve. Furthermore, research has shown that wrist positions which deviate from neutral increase carpal tunnel pressures placing increased tension and pressure on the median nerve.[19]

A negative correlation of cervical core muscle endurance with smartphone addiction on the PUMP Scale as well as duration of smartphone use implies that the cervical core endurance is less in individuals who use their smartphone for longer durations and in those who are more addicted.

The results of this study are consistent with a study by Lee et al. which found that a longer duration of smartphone use leads to a higher neck flexion angle.[20] A study performed by Gong et al. reported that posture of the cervical spine has a greater effect on the endurance than on the strength of the deep neck flexors.[21] Furthermore, previous research concluded that participants who were excessive smartphone users had an abnormal craniovertebral angle as compared to those who were not.[2] This could thereby alter the length–tension relationship of muscles around the cervical spine. As the ability of a muscle to generate force is influenced by its length, when a muscle is shortened or lengthened, its ability to generate force is reduced.[22]

Furthermore, the “double-crush mechanism” explained by Duyur et al. could be a reason for the affection to the median nerve. Due to increased neck flexion or extreme wrist postures attained during smartphone use, the median nerve could be compressed either at the cervical spine or in the carpal tunnel leading to a deterioration of axonal conduction, thus resulting in other parts of the nerve becoming more sensitive due to the increased mechanosensitivity.[23]


  Conclusion Top


The neural tissue mobility of the median nerve is hampered with increased smartphone use. Furthermore, the cervical core endurance is less in individuals who use their smartphone for longer durations and in those who are more addicted.

Clinical implications

  1. The results of the study could be employed in educational programs and thus create awareness about the correct posture when using a smartphone for extended periods
  2. Students should make a conscious effort to reduce the amount of time spent on a smartphone along with implementing other preventive measures. These include maintenance of correct posture during usage, taking frequent short breaks, and usage of voice to text software
  3. Furthermore, endurance training of the deep neck flexors and neural mobilizations of the median nerve can be given to healthy smartphone users before the development of musculoskeletal symptoms in the upper quadrant.


Future scope of study

Further research can be carried out on a larger cohort in order to obtain results that can be generalized to the whole population.

Acknowledgment

We would like to thank our Dean for allowing us to conduct the study in the institution premises. We would also like to thank our HOD Dr. Mrs Chhaya Verma for her guidance. We would also like to specially acknowledge the participants for their valuable time and cooperation given for the study, without whom this study would not have been possible. Special thanks to Ms. Vaibhavi Rathod for her valuable inputs and suggestions.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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2.
Akodu AK, Akinbo SR, Young QO. Correlation among smartphone addiction, craniovertebral angle, scapular dyskinesis, and selected anthropometric variables in physiotherapy undergraduates. J Taibah Univ Med Sci 2018;13:528-34.  Back to cited text no. 2
    
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Kim EY, Kim KJ, Park HR. Comparison of the effects of deep neck flexor strengthening exercises and Mackenzie neck exercises on head forward postures due to the use of smartphones. Indian J Sci Technol 2015;8:569-75.  Back to cited text no. 3
    
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Deborah Condon. Heavy Smartphone use may Damage Nerves; 2017. Available from: http://www.irishhealth.com/article.html?id=25855. [Last accessed on 2017 Nov 18].  Back to cited text no. 5
    
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Balakrishnan R, Chinnavan E, Feii T. An extensive usage of hand held devices will lead to musculoskeletal disorder of upper extremity among student in AMU: A survey method. IJPESH 2016;3:368-72.  Back to cited text no. 7
    
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Hulley SB, Cummings SR, Browner WS, Grady D, Newman TB. Designing Clinical Research: An Epidemiologic Approach. 4th ed.. Philadelphia, PA: Lippincott Williams and Wilkins; 2013. p. 79. Available from: http://www.sample-size.net/correlation-sample-size/. [Last accessed on 2020 Mar 24].  Back to cited text no. 8
    
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Lee J, Sueb Song H. The correlation analysis between hours of smartphone use and neck pain in the Gachon university students. Acupuncture 2014;31:99-109.  Back to cited text no. 9
    
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Merlo LJ, Stone AM, Bibbey A. Measuring problematic mobile phone use: Development and preliminary psychometric properties of the PUMP Scale. J Addict 2013;2013. Article ID 912807, 7 pages.  Back to cited text no. 10
    
11.
James G, Doe T. The craniocervical flexion test: Intra-tester reliability in asymptomatic subjects. Physiother Res Int 2010;15:144-9.  Back to cited text no. 11
    
12.
Fernandez-de-las-Peñas C, Pérez-de-Heredia M, Molero-Sánchez A, Miangolarra-Page JC. Performance of the craniocervical flexion test, forward head posture, and headache clinical parameters in patients with chronic tension-type headache: A pilot study. J Orthop Sports Phys Ther 2007;37:33-9.  Back to cited text no. 12
    
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Magee DJ. Orthopedic Physical Assessment. 5th ed.. Missouri US: Elsevier; 2008. p. 164-5.  Back to cited text no. 13
    
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Byng J. Overuse syndromes of the upper limb and the upper limb tension test: A comparison between patients, asymptomatic keyboard workers and asymptomatic non-keyboard workers. Manual Ther 1997;2:157-64.  Back to cited text no. 14
    
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Shahanawaz SD. Upper limb neural tissue extensibility in apparently asymptomatic professional computer users. ARC J Neurosci 2016;1:19-25.  Back to cited text no. 15
    
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Alruzayhi M, Almuhaini M, Alwassel A, Alateeq O. The effect of smartphone usage on the upper extremity performance among Saudi Youth, KSA. Romanian J Rhinol 2018;8:47-53.  Back to cited text no. 16
    
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Gong W, Kim C, Lee Y. Correlations between cervical lordosis, forward head posture, cervical ROM, and the strength and endurance of the deep neck flexor muscles in college stduents. J Phys Ther Sci 2012;24: 275-7.  Back to cited text no. 21
    
22.
Lee KJ, Han HY, Cheon SH, Park SH, Yong MS. The effect of forward head posture on muscle activity during neck protraction and retraction. J Phys Ther Sci 2015;27:977-9.  Back to cited text no. 22
    
23.
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