The Head Down Generation: Musculoskeletal Symptoms and the Use of Smartphones Among Young University Students

Abstract

Background:

Smartphones offer a variety of mobile applications for diverse purposes and access to services that contribute to an increased time of interaction with the device, influencing the users' health and behavior.

Introduction: The time of interaction with smartphones is more intense with the younger generation, and physical, psychological, and social complications are reported. This research aims at identifying the factors associated with musculoskeletal symptoms due to the use of smartphones in university students in Brazil.

Materials and Methods: The study has a quantitative transversal type approach, with 522 college students between the ages 18 and 26. A structured questionnaire was applied in 2017, to characterize the sociodemographic profile, composed of information regarding the use of smartphones added to the Nordic questionnaire of musculoskeletal symptoms.

Results: One of the main results found was a tendency for participants to have symptoms of musculoskeletal pain with regards to their typing methods on smartphones. When asked about the cases when such symptoms were considered to be related to the use of the device, most cited the cervical region (43.87% of cases). It was also found that those who type on their phones with the head at 45

° and 60° angles are about twice as likely to have higher scores of severe symptoms than those typing with their neck at 0° (anatomical position).

Conclusion: Within the university student population the typing position on a

smartphone and time of use are associated with the presence of pain in the cervical region.

Introduction

Smartphones offer a variety of mobile applications for diverse purposes such as entertainment, communication, and access to services that contribute to an increased time of interaction with the device, influencing the users' health and behavior.^1,2 Lepp and Barkley identified a negative relationship between smartphone use and health, where the main reports of problems were related to smartphone addiction,^3,4 social isolation,⁵ sleep disturbances,^6,7 depression and anxiety,^8,9 phobias,¹⁰ and accidents while walking¹¹ or driving.^12
–14 Other research also associates the time of interaction with musculoskeletal symptoms, mainly in the younger population.^15

–18

This population is composed of a large number of students, including those at the university level, who use the device for academic purposes.¹⁹ The younger generations are digital natives born in the age of mobility and use the technology in different contexts in their daily lives. Consequently, they are more prone to be affected by musculoskeletal symptoms through the use of smartphones, as seen in studies with populations from Korea,^17,20 China,²¹ Canada,²² Switzerland,²³ as well as other studies comparing young Americans and Koreans.²⁴ In Brazil, only one study by Damasceno et al.²⁵ evaluated the perception of posture associated to neck pain in young people, but they were students in a single public high school.

Taking into account the group's experience in identifying the social and cultural impacts of the use of technologies,^26,27 as well as the evaluation of technologies and health consequences, the objective of this article was to identify factors associated with musculoskeletal symptoms due to the use of smartphones in Brazilian university students. The intent was to identify those students exposed to this problem, understand this negative interaction resulting from the use of the smartphone, and provide subsidies for future actions within the educational scope and promote health. Most of the previous studies on musculoskeletal injuries in relation to the use of a certain technology were based on the use of computers by students. However, today, students interact with smartphones for longer and more frequently compared to computers.²⁸ Gold and colleagues²⁹ demonstrate that uncomfortable postures, strength, and repetition actions are associated with the risk of musculoskeletal disorders. The typing styles and smartphone characteristics (with/without physical keyboard) influence the postures, as well as the intensity and the frequency of muscular activation, and inappropriate behavior of interacting can lead to tingling, numbness, and pain.³⁰ If there are no changes and these conditions remain, users are negatively affected as to their quality of life.

Materials and Methods

The study is characterized by a quantitative, descriptive, cross-sectional observational approach among university students aged 18–26 years at a higher education institution in Brazil. A questionnaire was applied to characterize the student profile, with questions regarding their interaction with smartphones and musculoskeletal symptoms. As inclusion criteria, the participant had to be classified as an “active typist,” referring to those who send at least 25 text messages or e-mails a day and browse the internet or play games for more than 1 h/day using their smartphones.¹⁶ We excluded individuals who reported these interactions through other portable devices (e.g., mini-game consoles) and individuals diagnosed with repetitive strain injury (RSI) or work-related musculoskeletal disorders (WMSDs) in the regions of the spine, neck, shoulders, arms, or hands.

Procedures for Data Collection

The online sociodemographic questionnaire was combined with the Nordic Questionnaire on Musculoskeletal Symptoms.³¹ We used a web banner, in the main page of the virtual learning environment (Moodle), displayed for 30 consecutive days, beginning on May 13, 2017. Students are advised to access Moodle regularly (at least once a week) so they can perform complementary activities for their undergraduate education.

Instruments for Data Collection

Structured sociodemographic questionnaire

The sociodemographic questionnaire based on the studies of Berolo et al.³² and Sharan et al.¹⁶ was applied for issues related to smartphone use. It consists of block of questions with sociodemographic profile and physical activities of the student, habits and forms of interaction with the smartphone, products and services most accessed, and where and how (posture) the interaction is done the most. To indicate area and intensity of pain, we used the Visual Analog Scale, a one-dimensional instrument for the evaluation of pain intensity, numbered 0 to 10, 0 being “no pain” and 10 being “maximum pain”.³³ The perception of the body image itself during the use of the smartphone was based on the study done by Hansraj³⁴ who proposed a figure of one side of the body to allow the student to mark the flexed angle of the neck and head most used when on his/her smartphone. It also indicates which region of the body feels the most pain.

Nordic musculoskeletal questionnaire

To measure musculoskeletal symptoms we adopted the Nordic Musculoskeletal Questionnaire in its specific form for the neck and shoulder region validated in the Portuguese language³⁵ facilitating the comparison of the results between the associated factors.

The participant identified on the body map the presence of pain, discomfort, tingling/numbness within the last 12 months and within 7 days before the gathering, and if, as a consequence of such pain, he/she could not perform the daily activities, had to take some time off, or sought health professional care, in the last 12 months. The second part was composed with questions regarding the symptomatic regions, where the participants indicated whether they believe that the reported symptoms are related or not to the use of the smartphone.

Data Analysis

To investigate the possible associations between typing styles and area with pain, as well as the typing position and area with pain, the chi-square association test was applied. Later, to evaluate the relationship and influence in the number of hours of use per day, the dominant hand, and the posture of greater interaction with the smartphone with the symptom severity score, a regression model was used. And, to compare the distribution of the symptom severity score between the categories of hours of use of the smartphone per day, the dominance of the hand, and the posture of greater interaction, we used the Kruskal–Wallis test.

Ethics Statement

The study was approved by the Ethics Committee in the Centro Universitário de Maringá–UNICESUMAR, Brazil (approval no. 1.953.069).

Results

A total of 1,083 questionnaires were answered whereby after applying the exclusion criteria, we reached the number of 522 (139 excluded [RSI/WMSDs]/331 [not active users]/91 [use other devices rather than smartphones]).

The majority of the students were female (62.84%) between 18 and 20 years (50.19%) and between 21 and 23 years old (37.93%). Regarding activities and physical activities, most respondents considered themselves to be sedentary (55.36%). It was observed that 87.74% of the students were right-handed. Most of them (77.97%) predominantly hold the smartphone with both hands and type with both thumbs (Table 1), 14.75% hold it with the right hand and type with the right thumb, and very few have different typing styles. More than half of respondents estimate their daily use of smartphones to be more than 5 h at home or everywhere else. The posture in which students see themselves interacting more with the smartphone is seated (68.97%) (Table 1).

Table 1.

Absolute (and Relative) Frequencies of Habits and Customs Regarding the Smartphone of the Research Participants (n = 522)

FACTORS	INCLUDED
FACTORS	FREQUENCY	%
Dominance of hand using the smartphone
Holds with right hand and types with left hand	8	1.53
Holds with right hand and types with right thumb	77	14.75
Holds with left hand types with right hand	16	3.07
Holds with left hand types with left thumb	14	2.68
Holds with both hands and types with both thumbs	407	77.97
How many hours is the smartphone used per day
Less than 2 h	23	4.41
2–3 h	66	12.64
3–4 h	83	15.90
4–5 h	82	15.71
More than 5 h	268	51.34
Postures adopted while using smartphone
Laying down on my back	88	16.86
Laying down on my stomach	13	2.49
Laying down on one side	40	7.66
Standing up	21	4.02
Sitting	360	68.97

Table 2 shows that more than half (61.49%) reported having had a problem (such as pain and discomfort) in the last 12 months in the neck region, whereas little more than one fourth (25.48%) reported having had problems in the last 7 days. The shoulders and dorsal region were responsible for reported problems in the last 12 months, with almost half of them indicating that they felt impaired in these regions after interaction with the device (46.17% and 44.44%, respectively).

Table 2.

Absolute (and Relative) Frequencies of Ergonomic Interference in Four Different Situations, Reported by Participants in the Research (n = 522)

REGION	PROBLEMS (LAST 12 MONTHS)	AVOIDED ACTIVITIES (LAST 12 MONTHS)	CONSULTED A PROFESSIONAL (LAST 12 MONTHS)	PROBLEMS (LAST 7 DAYS)
Neck
No	201 (38.51%)	489 (93.68%)	498 (95.4%)	389 (74.52%)
Yes	321 (61.49%)	33 (6.32%)	24 (4.6%)	133 (25.48%)
Shoulders
No	281 (53.83%)	496 (95.02%)	503 (96.36%)	433 (82.95%)
Yes	241 (46.17%)	26 (4.98%)	19 (3.64%)	89 (17.05%)
Dorsal area
No	290 (55.56%)	496 (95.02%)	491 (94.06%)	425 (81.42%)
Yes	232 (44.44%)	26 (4.98%)	31 (5.94%)	97 (18.58%)
Elbow/forearm
No	407 (77.97%)	513 (98.28%)	518 (99.23%)	490 (93.87%)
Yes	115 (22.03%)	9 (1.72%)	4 (0.77%)	32 (6.13%)
Lumbar area
No	263 (50.38%)	480 (91.95%)	473 (90.61%)	423 (81.03%)
Yes	259 (49.62%)	42 (8.05%)	49 (9.39%)	99 (18.97%)
Wrists/hands/fingers
No	258 (49.43%)	488 (93.49%)	511 (97.89%)	445 (85.25%)
Yes	264 (50.57%)	34 (6.51%)	11 (2.11%)	77 (14.75%)

A total of 22.03% reported having problems within the last 12 months in the areas of the elbow/forearm. The lumbar region caused problems in 49.62% and 18.97% of students in the last 12 months and 7 days, respectively.

When questioned about the relationship between the signs and symptoms with the use of the smartphone, the area most mentioned was the cervical region (43.87%), followed by hand/wrist (30.87%).

Regarding the postural position in which the respondent fits in the criteria for typing on the smartphone, it was verified that the majority (36.97%) type with a 30° inclination of the neck when standing or sitting.

As shown in Table 3, sufficient sample evidence was not observed to affirm the existence of a significant association between typing style and the region with the pain. In contrast, it is noted that the typing position is significantly associated with the region where there is pain in general (p = 0.002).

Table 3.

Results for the Chi-Square Association Test Between the Selected Variables

VARIABLES	χ²	DL	p
Typing style × region of pain (right hand)	26.44	24	0.3311
Typing style × region of pain (right hand)	32.56	24	0.1137
Typing style × region of pain	20.37	16	0.2039
Typing position × region of pain	36.79	16	0.0022^*

p value ≤0.05.

DL, degrees of liberty.

According to Table 4, it can be observed that in regards to the number of hours of smartphone use per day, individuals using the device from 4 to 5 h tend to present a higher score for symptoms of severity than those with less than 2 h of use. Still, those who type on a smartphone with the neck position bent at 45° and 60° have almost twice the odds of presenting higher severity scores of musculoskeletal symptoms than those typing in the 0° position.

Table 4.

Estimates of the Parameters for BEZI Regression Model Adjusted to the Sample Data

	ESTIMATE	STANDARD ERROR	p
Intercept	−2.03	0.43	0.000^*
Hours of smartphone use per day (less than 2 h)
2–3 h	0.21	0.14	0.149
3–4 h	0.12	0.14	0.402
4–5 h	0.27	0.12	0.027^*
More than 5 h	0.09	0.20	0.646
Dominance of hand using the smartphone (holds device with right hand and types with the left)
Holds with the right hand and types with the right thumb	0.17	0.30	0.572
Holds with left hand and types with right hand	0.30	0.34	0.386
Holds with left hand and types with left thumb	−0.27	0.38	0.479
Holds with both hands and types with both thumbs	0.02	0.29	0.956
Posture of greater interaction with smartphone (laying down on back)
Laying down on stomach	0.34	0.22	0.115
Laying down on one side	0.19	0.15	0.190
Standing up	0.02	0.20	0.934
Sitting	−0.07	0.10	0.490
Position when typing on smartphone (0°)
15°	0.34	0.29	0.236
30°	0.45	0.29	0.116
45°	0.66	0.29	0.023^*
60°	0.64	0.30	0.033^*

p value ≤0.05.

Discussion

Our results indicated that some types of behaviors when using a smartphone are factors associated with musculoskeletal symptoms in university students.

We found that more than half of the students considered themselves to be sedentary. It is known that the addiction and time of use of the smartphone can negatively influence physical health, by reducing the amount of daily physical activity, such as walking. Kim et al.³⁶ had already shown that students in Korea dependent on smartphones were less likely to walk on a daily basis. Physical exercise can be considered as an act of prevention, since it can help prevent the onset of musculoskeletal pain and general harm to health.³⁷

As for habits of interaction with smartphones, we noticed that regardless of the predominant hand (right-handed = 87.74%), problems arising from incorrect use can jeopardize all individuals. Of the students, 407 (77.97%) indicated typing in a nonrecommended way, which is when they were using both hands to hold the smartphone and typing on the screen only with their thumbs. Ko et al.³⁸ recommend holding the smartphone with just one hand and typing with the other hand using the index finger and avoiding using only the thumbs. In our data, only 1.53% of those who reported holding the device with the right hand and typing with the left and 3.07% of those holding with the left hand and typing with the right were doing so as recommended by the researchers. The determination of “right” and “wrong” for typing style takes into account ergonomic aspects of most devices, as well as biomechanical aspects of the interaction.^39,40

We found that typing styles during smartphone use did not show enough evidence to significantly affirm a correlation with musculoskeletal symptoms. Nevertheless, we noted that there is a propensity to pain with these styles of interaction. This noncharacterization sample of symptoms may be associated with the reports done by Gold et al.⁴¹ where they affirm that typing on a mobile device may put users at risk of musculoskeletal injuries, and future research should include longitudinal epidemiological studies to determine if posture and typing risks identified may be associated with musculoskeletal injuries. In addition, with regard to habits, more than half of the students estimated that their daily interaction with the device was superior to 5 h, and only 4.41% reported using it for less than 2 h. Our data are close to what Kong et al.⁴² found when they noted that about 56% of the population in the United States use smartphones, and the average time spent per day is 5.1 h. Hansraj³⁴ further confirms the average time people spend per day on their smartphones and associates this navigation period with significant postural changes. In the same context, a survey conducted in Canada by Xie et al.²² with 137 college students, staff, and teachers concluded that participants spend more than 4.65 h/day on a smartphone. Of the respondents, 67.05% of those using the device reported using it for 4 h or more and indicated a tendency to have pain.

Main Body Areas and Distribution of Number of University Students with Reported Musculoskeletal Symptoms

It was possible to see in our research that the most affected area of the body due to excessive typing was the neck (cervical region) reported by 43.87% of those included in the study; subsequently, the wrist/hand/finger region presented an index of 30, 46% of reported pain associated with smartphone use. In contrast, the less cited region was the elbow (3.45%). Observational and experimental studies show us important ergonomic alterations in posture and muscle activity during smartphone use.^14,43 The use of this device tends to result in a flexed neck with prolonged periods of flexed arms.⁴⁴ Surface electromyographic examination techniques were used to measure the increased activation of the extensor muscles in the neck and thumbs with the habit of text messaging on a smartphone.⁴⁵ The highest activation in these muscle regions is positively correlated with pain in the neck, shoulder, and wrists.^45,46

Those who use smartphones flex their head forward or flex the arm continuously. Thus, this posture is an important factor in explaining pain in the neck, shoulders, and hands. A survey of more than 3,000 Chinese high school students assessed that the impact of using mobile devices for more than 2 h a day was associated with an almost 50% increase in the risk of neck pain.⁴⁷ Meanwhile, higher rates of physical activity were associated with a reduced rate of neck pain. Therefore, the duration of the use of the device and the level of physical activity have been important factors when considering the relationship between the device and neck pain.

University Student's Posture While Using a smartphone

The postural and biomechanical mechanism when flexing the neck was translated into an estimate of body perception during the use of the device in our study. Thus, we were able to observe, through associative sampling analysis, the direct relationship of the postural angles of the neck and the musculoskeletal symptoms in the cervical region. When asked about body perception, more than a third of the students (35.06%) reported having pain in the neck. This shows that those typing on a smartphone with their heads tilted at 45° and 60° angles are almost twice as likely to have severity score symptoms of 1 compared to those typing in the 0° position. This similarity to typing angles was found by Lee et al.⁴⁸ where they examined the effects of cervical flexion angle on muscle fatigue and pain in the cervical spinal erector muscles and upper trapezius fibers in adults aged 20 years. The results of the study showed statistically significant differences in muscle fatigue and pain in the upper right and upper left trapezius. Depending on the angle of cervical flexion, they showed statistically significant levels of fatigue and muscular pain at 50° than at 0° or 30°. It is implied that the angle of cervical flexion during the use of the smartphone can influence muscle fatigue and pain in the upper trapezius.

This biomechanical mechanism of looking down to check the smartphone anteriorly flexes the neck, and the pressure on the cervical spine is multiplied. The neck supports the head while protecting the integrity of the spinal cord. With the best postural presentation, the cervical spine maintains an anterior lordotic curvature to support the weight of the head, which on average weighs about 10 kg. As the neck flexes forward, the cervical curvature decreases and the head's weight increases dramatically. In this perspective Kim⁴⁹ indicates that individuals who adopt this posture of greater neck flexion when using a smartphone are more susceptible to the painful mechanism in the cervical region and wrists and should be aware of their posture and thus modify their cervical alignment.

Limitations of the Study

The generalization of the results presented should consider the inherent limitations of the cross-sectional studies that use self-filling instruments. Our research had university students as a population, and it is important to evaluate the differences between other age groups. Although some studies have observed a higher prevalence in the Middle East and East Asian populations, studies comparing different nationalities are still needed.^4,24 In our research, we present data for Brazilian students enrolled in a private university in the south of the country. However, the geographic and sociocultural coverage of the country requires comparative studies or includes a larger number of participants especially if we consider that access to broadband and mobile telephones is not equally available in all regions of the country.⁵⁰

Conclusion

We confirm the evidence presented in previously reported research.^{15,16,18,20,32,48,49} It is important to understand all the biomechanical and physiological processes of the body and the activities of interaction with smartphones, which already suggest a direct relationship as a predominant factor to the painful mechanism in young students.

We confirm that there is an association between time and posture when using the smartphone and the occurrence and reports of pain. In the long term, these problems can qualitatively affect the lives of individuals, without taking into account the emotional and social harms of this interaction. Because the use of smartphones is an irreversible trend we highlight the need for health educational programs that alert to musculoskeletal disorders, promoting change of habits, and provide incentives to practice physical activities.

It is increasingly more common to see individuals with their “heads down,” touching with their fingers the bright screen, seduced by the content in those devices. These are contexts present in today's society, which condition some behaviors that may not be healthy. Faced with this panorama, sometimes gloomy and real, it is relevant to point to perspectives that alert to the quality of the interaction with the device.

Footnotes

Acknowledgment

To CAPES Foundation for the scholarship.

Disclosure Statement

No competing financial interests exist.

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