The influence of educational intervention, according to ergonomic principles on neck and shoulder disability and pain indices relevant to smartphones, among students

Abstract

BACKGROUND:

The increasing usage of smartphones by students has caused awkward ergonomic postures which have led to musculoskeletal pain and disabilities, especially in the neck and shoulder, the purpose of the current study is the reduction of neck and shoulder pain and disability, via an educational intervention, according to comprehensive ergonomic principles.

MATERIALS AND METHODS:

The current study, which was an educational intervention, has been implemented with both intervention and control groups in the form of pre-test and post-test, including intervention group control group, in the years, 2023 and 2024 in Iran. Participants from both separate schools of Shahid Beheshti University of Medical Sciences completed the NDI (Neck Disability Index), DASH (Disabilities of the Arm, Shoulder, and Hand) questionnaires, and VAS (Visual Analog Scale) to determine the disability and pain indices in both neck and shoulder, and then, the educational intervention was conducted, for the ergonomic usage of smartphone, during three consecutive days, after two months (eight sessions for reminding which considered one session per week) of implementation of the program by the volunteers. Participants completed the mentioned questionnaires again, and then, data analysis was conducted by statistical software SPSS version 23.

RESULT:

The findings depict more NDI, compared to DASH and more Neck-VAS, compared to Shoulder-VAS, as well as, NDI (P = 0.003), DASH (P = 0.001), Neck-VAS (P = 0.000), and Shoulder-VAS indices (P = 0.041) have statistically been decreased significant, among the post-test intervention group, compared to the pre-test intervention group, in addition to, the four last mentioned indices have statistically been reduced significant, respectively (P = 0.005), (P = 0.043), (P = 0.04), and (P = 0.006) among the post-test intervention group, compared to the post-test control group.

CONCLUSION:

The training in the ergonomic principles of Stanford University can reduce neck and shoulder pain and disability indices among smartphone users.

Introduction

The widespread usage of smartphones by a high number of individuals,[1] with the rate of usage in Iran up to 77.72 millions of people in 2023[2] and among developed countries, including China, India, and the United States orderly, 974.69, 659, 276.14 millions of people in 2022 which can be high.[3] It has led to the creation of awkward ergonomic postures which have caused the prevalence of musculoskeletal disorders among various types of population groups in the societies,[4] especially with the expansion of virtual education, due to the COVID-19 pandemic and also virtual learning, the use of smart electronic devices and smartphone screens for study purposes among individuals have increased.[5,6,7] Despite numerous studies on the prevalence of neck and shoulder pain and disability, there is a comprehended need for the development of an educational program in accordance with ergonomic recommendations and protocols for mitigating pain and disability indices in the neck and shoulder among smartphone users. In fact, the usage of smartphones is not limited to calls and texting nowadays, but also at the national level, the rate of usage of smartphones by Iranian students is high because, despite the disadvantages of excessive usage of smartphone, it is a tool for dealing with personal issues and performing daily tasks, including in search of information like conducting researches, taking photographs and videos, entertainments, academic tasks, such as educations and assignments, earning income, escaping from real life, passing time, communicating with family, communicating with friends, interacting and conversing with the opposite sex for the purpose of being seen and heard in community, which one of them is related to academic works, such as conducting assignments and teaching lessons.[8] The prevalence of musculoskeletal disorders through the usage of smartphones in the neck area is high up to 49.6% and the intensity of moderate to severe disability caused by long-term usage of smartphone in the neck area has been reported up to 42.5% among students,[9] also the intensity of shoulder pain among students is significant up to 42.9%,[10] awkward postures, including holding smartphones in a two-handed posture, compared to a one-handed posture cause more flection in the neck area[11] and can also lead to musculoskeletal disorders in the shoulder area,[12] while gender difference is not a significant risk factor in the amount of neck flection,[13] seated postures, compared to standing postures cause more neck flection,[14] in addition, repetitive postures,[15] as well as, the long-term usage of smartphones are key risk factors in the occurrence of pain and discomfort in the neck area,[16,17,18,19] repetitive arm and wrist postures, during smartphone usage cause an increase in the amount of force can be applied on the neck and shoulder.[20] One of the factors of spinal disorders, which causes disorders in the shoulder, is caused by the long-term usage of smartphones,[14,21] musculoskeletal problems caused by the use of smartphones may initially be short-term but if appropriate precautions are not considered, they can cause long-term disabilities in individuals,[9] during the usage of smartphones, including texting and watching the screen of smartphone for reading the text of books and articles, the upper limbs are the most stuck, also measuring the level of fatigue of the cervical spine muscles and the upper part of the trapezius muscle with electromyography during smartphone use has shown that pain and fatigue worsen with longer usage of smartphones,[16] in addition, even short periods of usage up to 20 minutes of performing tasks with the help of a smartphone, it has shown pain and discomfort in the upper limbs of the shoulder and neck area,[22] in which the highest level of discomfort, based on previous studies, has been reported in the shoulder, neck, and back,[22,23] providing that ergonomic training with the help of smartphones has cognitive benefits for young people,[24,25] in fact, there are various methods, including surgery, exercises, and feedback, to improve and control posture, one of these methods is the improvement of users’ awareness.[4] Hence, the ergonomic guideline should consist of advices on how to interact with handheld electronic devices to achieve a relaxed posture and reduce muscle load for declining the risks of musculoskeletal disorders. Therefore, based on the collection of a set of needs in accordance with the ergonomic needs of smartphone users, including ergonomic posture, the duration of use of smartphones, short and intermittent rests during smartphone usage, and appropriate stretching movements which include benefits, such as reducing muscle tension, promoting better posture, reducing pressure and stress, improving blood flow, improving the range of motion, and increasing the flexibility of students,[26] during smartphone usage, also conducting researches for the best educational-ergonomic program which matches the needs mentioned, based on previous studies, indeed the Stanford ergonomic guide which is a set of ergonomic guidelines regarding the ergonomic posture of holding smartphones and the appropriate way of typing, paying attention to neck posture, short and intermittent rests to eliminate repetitive and static postures, light stretching movements, paying attention to the duration smartphone usage, as well as, the appropriate posture for conversation and supplementary features such as voice typing,[26,27,28,29] has the most adjustment to the mentioned goals for assessing the efficiency of this program in an interventional study for ergonomic usage of this electronic device. This study has endeavored to reduce the disability and pain indices of the neck and shoulder associated with smartphone users among the students through the implementation of the Stanford University ergonomic protocol, via educational intervention, an innovative part of the current study is merging stretches, postural modifications, and the elimination of static postures under an united program for intervention by focusing on both neck and shoulder which are under dangerous more than other areas of body, because of the rate of muscular skeletal disorders in Iran, in fact, the second position about neck pain belongs to Iran (1055.5 incidence per 100000), after Norway (1145 incidence per 100000), at the global level.[30]

Material and Methods

Study participants and sampling

The current study, which was a semi-experimental controlled pre-test and post-test ergonomic educational intervention, was conducted over two months with the participation of both intervention and control groups, including men and women, in the years 2023 and 2024, with the sample size (n = 53) determined by formula with 95% confident level,[31] an average (d = 17.37%-12.89%), standard deviation (SD = 7.5),[32] and possibility of 20 percent of departing the study, during intervention. The sampling method was nonrandom sampling, because it was a semi-experimental study, and participants were from two separate medical science colleges among undergraduate students. Ethical considerations were observed, including the approval of the consent form consisting of exiting the study by individuals every time, students’ satisfaction, human dignity, no invasive intervention, respect for individuals’ engagements by the volunteers, and the examination of the entry criteria for the study, which included not having a background of musculoskeletal disorders, including upper limb surgery, or a hereditary history of musculoskeletal disorders.[22] In addition to, disability, pain, and musculoskeletal disorders resulting from an accident, including an accident, surgery, or any sudden event that led to the onset of these symptoms, during the intervention, were considered to be avoided. To eliminate distorting factors, both intervention and control groups must not have significant differences in background variables. For this purpose, background variables include (age, sex, hours of using smartphones during the day, weight, height, type of phone brand) were measured between the control and intervention groups to homogenize both groups statistically, furthermore, any paramedical action, such as physiotherapy or the use of medicines were related to neck musculoskeletal disorders, acupuncture, occupational therapy, or starting a stretching-sports activity, were considered as intervening factors and exiting criteria for the study, after the start of the ergonomic educational intervention. Hence, volunteers from both groups were asked to report the mentioned cases to eliminate intervening environmental variables.

Study design and setting

The implementation steps of the study are as follows (according to Figure 1):

Figure 1.

Material and methods flowchart

The first step (demographic information collection)

Demographic information was obtained through the completion of a demographic questionnaire by the volunteers, including gender, age, height, weight, average hours of cell phone use per day,[33] type of phone brand, the extent of computer use during the day, and the status of stretching-gym activities.

The second step (pre-test on the intervention and control groups)

Individuals from the intervention and control groups reported their history of pain and disability in the neck and shoulder areas through the Neck Disability Index (NDI) and DASH questionnaires,[34,35] which were distributed with the help of (docs.google.com/forms) via, social networks such as, Telegram, WhatsApp, and email, as well as, by the paper and pencil version. A Visual Analog Scale[36] was also used to determine the severity of pain and discomfort in each shoulder and neck member. The goal of this step was to determine the baseline level of musculoskeletal pain and disability resulting from smartphone use in both intervention and control groups to compare the severity of neck and shoulder pain to determine educational priority during the development of the educational program, as well as, to compare with post-test results.

The third step

The development of an educational program, according to needs assessment and ergonomic educational intervention, according to the findings and the review of previous studies, an educational program, based on the ergonomic principles of smartphone usage was conducted for the intervention group. First of all, reviews of resources with keywords were related to Google’s search engine and Microsoft’s artificial intelligence was conducted. Then, based on the educational program’s goals, educational contents were related to ergonomic principles of the neck and shoulder associated with electronic devices, such as smartphones, tablets, and computers were collected. The educational program had to be translated into Persian, and after determining the quality of the educational content according to the goals, an educational program was prepared in the form of PowerPoint files, PDFs, and three instructional videos, including principles of posture during smartphone usage, micro-breaks, the importance of muscle stretching during smartphone usage, and a video on ergonomic principles of computer usage as an alternative task to smartphones during the long periods of study and texting, all of them was the proportion of the Stanford University ergonomic guideline.[26,27,28,29,37,38,39] In addition to, instructional images related to ergonomic principles were created, afterward, the educational content was trained to individuals, according to Schedule which is visible, via [Table 1], over three consecutive days of educational intervention, and eight sessions (once a week for two months) for reminding the educated ergonomic principles with the help of images, short sentences, and short files, during the implementation of the educational program, students’ questions about ergonomic principles were responded to clarify any ambiguities, control group was only appreciated by examiner at end of the study through a reward which was the educational program, after filling in the questionnaires by control group.

Table 1.

The content of ergonomic training sessions during, the usage of smartphones for two months

Steps		Educational schedule		Sessions
Intervention (training)		The introduction includes the explanation of the relationship between the use of smartphones and the resulting pain and discomfort in smartphone users. It also covers the education of the ergonomic posture of the hands, while holding and using the smartphones, as well as, the ergonomic posture of the neck and head, during smartphone usage.		1
Intervention (training)		Instruction on how to eliminate static, repetitive, and prolonged postures during the use of smartphones, including suggestions for short and intermittent rest periods known as Micro-breaks.		2
Intervention (training)		Description of the benefits of short-term and intermittent muscle stretching as a form of brief and intermittent rest during smartphone use. Additionally, instruction on four muscle stretching routines that help reduce muscle tension, promote better posture, decrease pressure and stress, improve blood circulation, enhance the range of motion, and increase flexibility in the neck, shoulder, fingers, back, wrist, and arm.		3
Implemented by the target group—Reminders and follow-ups.		Reminders and follow-ups on training through the distribution of images, educational texts, and also educational clips via virtual space and social networks.		4
Implemented by the target group—Reminders and follow-ups.		Responding and clarifying questions raised by smartphone users with the help of virtual space and social networks regarding the educational program.		5
Implemented by the target group—Reminders and follow-ups.		Reminders and follow-ups on training through the distribution of images, educational texts, and also educational clips via virtual space and social networks.		6
Implemented by the target group—Reminders and follow-ups.		Reminders and follow-ups on training through the distribution of images, educational texts, and also educational clips via virtual space and social networks.		7
Implemented by the target group—Reminders and follow-ups.		Reminders and follow-ups on training through the distribution of images, educational texts, and also educational clips via virtual space and social networks.		8
Implemented by the target group—Reminders and follow-ups.		Responding and clarifying questions raised by smartphone users with the help of virtual space and social networks regarding the educational program.		9
Implemented by the target group—Reminders and follow-ups.		Reminders and follow-ups on training through the distribution of images, educational texts, and also educational clips via virtual space and social networks.		10
Implemented by the target group—Reminders and follow-ups.		Reminders and follow-ups on training through the distribution of images, educational texts, and also educational clips via virtual space and social networks.		11

The fourth step

Post-test was conducted on both the intervention and control groups, after two months, according to the duration of previous trial studies,[40,41] to evaluate the results of the implemented educational intervention, participants from the intervention and control groups were asked to complete the NDI, DASH, and VAS questionnaires again for assessing pain and disability in the neck and shoulder areas. To eliminate the effect of environmental factors, also comparing the results obtained via the intervention and control groups, the control group was required to complete the questionnaires, to evaluate whether the improvement or worsening of neck and shoulder pain and discomfort indices were because the educational intervention or other environmental factors had a positive or negative impact on the results.

The fifth step (data analysis)

For data analysis, after confirmation of the normality of the distribution of collected data, data analysis was conducted by both paired and independent t-tests, as well as, Chi-square for determining the statistical significance level of the indices of disability and pain in the neck and shoulder areas, between the findings which were related to before and after the intervention among the intervention group, also the results of the intervention on the intervention group were compared with the post-control group. All statistical evaluations were performed with SPSS version 23.

Data collection tools and technique

NDI Questionnaire: A reliable and valid tool for assessing neck pain which consists of ten items with a six-point Likert scale ranged from the least pain with a score of zero to the most pain with a score of five. The total score is a number between 10 and 50 with the highest score indicating severe neck disability, determining the severity of pain and disability in the neck area that causes disruption in personal tasks (such as bathing and dressing), reading, headache, concentration, working, driving, sleeping, and recreational activities.[34] Its reliability in the Persian version has been reported to be excellent, between ICC = 0.9 and ICC = 0.97, and the questionnaire has good convergent validity between 0.31 and 0.7.[42]

Visual Analog Scale (VAS): A tool for measuring pain intensity in different body areas. This scale consists of a 10-centimeter line with a label at both ends, with the left side indicating a state of no discomfort and the right side indicating severe discomfort. The subject marks the intensity of their discomfort on the scale line, and then, the severity of discomfort in each member is recorded numerically between zero and one hundred based on the distance of the mark from the left side of the scale line.[36]

DASH Questionnaire: A questionnaire with 30 items, where the response range for each item is between one and five, with 21 questions related to the number of individuals’ problems that deal with their daily tasks, five questions about the severity of pain during sleep and activity, and four questions about the impact of pain and discomfort in the shoulder and hands-on social activities and job performance. At least 27 questions must be answered, with a total score, ranging from 0 (no disability) to 100 percent (maximum disability).[35] The Persian version of this questionnaire has good convergent validity between 0.25 and 0.75 and excellent reliability with an interclass correlation coefficient of ICC = 0.82.[43]

Ethical consideration

To observe the research ethics, all participants were informed of the working method and objectives of the study, the information was kept confidential, and written consent was obtained from the individuals. The present study was conducted with the full approval of the ethics committee of the Shahid Beheshti University of Medical Science (Approval ID: IR. SBMU. PHNS. REC.1402.124)

Results

[Table 2] depicts the results obtained from the demographic characteristics and background variables in both control and intervention groups.

Table 2.

Demographic characteristics in both intervention and control groups

Group		Number		Number in total		variable		Amount, number		Amount, number		Amount, number		P
Intervention		53		117		Gender		Male (39.6%), (21)		Female (60.4%), (32)		-		0.238
Control		64						Male (28.1%), (18)		Female (71.9%), (46)		-
Intervention		53		117		Gym-stretching activity		Yes (39.6%), (21)		No (60.4%), (32)		-		0.562
Control		64						Yes (32.8%), (21)		No (67.2%), (43)		-
Intervention		53		115		Age		(21.77±3.66) Year		-		-		0.034
Control		62						(20.54±2.06) Year		-		-
Intervention		53		117		Computer usage		Low (69.8%), (37)		Moderate (13.2%), (7)		High (17%), (9)		0.789
Control		64						Low (62.5%), (40)		Moderate (31.3%), (20)		High (6.3%), (4)
Intervention		53		117		Height		1.71±0.089 Meter		-		-		0.357
Control		64						1.69±0.095 Meter		-		-
Intervention		53		117		Weight		69.96±16.23 Kg		-		-		0.076
Control		64						64.67±15.46 Kg		-		-
Intervention		52		115		Daily smartphone usage		5.49±2.57 hours per day		-		-		0.096
Control		63						4.69±1.94 hours per day		-		-

The distribution percentage of smartphone brands in both the intervention and the control groups is presented in Figure 2.

Figure 2.

Distribution of smartphone brands in both intervention and control groups

Findings based on aims of study

Similarity of both pre-test control and pre-test intervention groups for pain and disability indices, as well as, comparison between pain and disability in both neck and shoulder

Based on the findings presented in the Table 3, it depicted that the level of pain and disability in the neck area is greater than in the shoulder for both the intervention and control groups. The severity of pain, according to the Visual Analog Scale (VAS), was higher in the neck area than in the shoulder for both groups in the pre-tests. In addition to, the Neck Disability Index (NDI) is higher than the (DASH) Disabilities of the Arm, Shoulder, and Hand index in both the intervention and control groups, during the pre-tests. The statistical significance of the differences between the pre-test intervention and pre-test control groups for the NDI (P = 0.29), DASH (P = 0.37), VAS for neck pain (P = 0.37), and VAS for shoulder pain (P = 0.002) indicated that there was no significant difference (P > 0.05) except for the VAS for shoulder pain (P = 0.002); hence, both groups were similar toward each other to enter the study.

Table 3.

Four comparisons, according to aims of study (post-test control and pre-test control, post-test intervention and pre-test intervention, pre-test control and pre-test intervention and post-test intervention and post-test control

Results
Questionnaire		Group		Number		Average (%)		Standard deviation		Relative difference %		P		Types of comparisons
NDI-Post1		Intervention		50		8.92		5.89		38.48		0.005		Comparison between post-test-control and post-test intervention
NDI-Post		Control		40		14.5		10.89
DASH-Post2		Intervention		50		5.88		7.18		42.96		0.043
DASH-Post		Control		40		10.31		11.97
VASN-Post3		Intervention		50		14.6		12.1		33.63		0.04
VASN-Post		Control		40		22		19.5
VASS-Post		Intervention		50		9		14.4		53.84		0.006
VASS-Post4		Control		40		19.5		19.6
NDI-Pre5		Intervention		52		12.23		8.62		-		0.29		Comparison between pre-test-control and pre-test intervention
NDI-Pre		Control		61		13.96		8.63
DASH-Pre6		Intervention		53		8.71		9.72		-		0.37
DASH-Pre		Control		61		10.32		9.47
VASN-Pre7		Intervention		53		27.5		23.1		-		0.37
VASN-Pre		Control		61		31.4		23.7
VASS-Pre8		Intervention		53		14.7		19		-		0.002
VASS-Pre		Control		59		28.9		26.4
NDI-Pre		Intervention		50		12.44		8.62		28.29		0.003		Comparison between pre-test-intervention and post-test intervention
NDI-Post		Intervention		50		8.92		5.89
DASH-Pre		Intervention		50		8.8		9.92		33.18		0.001
DASH-Post		Intervention		50		5.88		7.18
VASN-Pre		Intervention		50		25.2		21.4		42.06		0.000
VASN-Post		Intervention		50		14.6		12.1
VASS-Pre		Intervention		50		13.8		17.8		34.78		0.041
VASS-Post		Intervention		50		9		14.4
NDI-Pre		Control		38		13.94		9.37		4.94		0.526		Comparison between pre-test-control and post-test control
NDI-Post		Control		38		14.63		11.17
DASH-Pre		Control		38		11.58		10.63		10.44		0.311
DASH-Post		Control		38		10.37		12.27
VASN-Pre		Control		38		31		22.7		33.22		0.001
VASN-Post		Control		38		20.7		18.9
VASS-Pre		Control		36		27.5		24.7		30.54		0.018
VASS-Post		Control		36		19.1		19.9

¹- Neck Disability Index—Post-test. ²- Disabilities of Arm, Shoulder, and Hand—Post-test. ³- Visual Analog Scale for Neck Pain — Post-test. ⁴- Visual Analog Scale for Shoulder Pain — Post-test. ⁵- Neck Disability Index—Pre-test. ⁶- Disabilities of Arm, Shoulder, and Hand—Pre-test. ⁷- Visual Analog Scale for Neck Pain — Pre-test. ⁸- Visual Analog Scale for Shoulder Pain — Pre-test

Comparison between pain and disability indices in post-test intervention group compared to before intervention (pre-test intervention group)

According to the results presented in the Table 3, there was a significant reduction (P < 0.05) in the indices of disability and pain in the neck and shoulder areas among the participants in the intervention group after the educational intervention, compared to before. Specifically, there was a significant decrease in the Neck Disability Index (P = 0.003), Disabilities of the Arm, Shoulder, and Hand (P = 0.001), Visual Analog Scale for neck pain (P = 0.000), and Visual Analog Scale for shoulder pain (P = 0.041). These results indicated that the ergonomic educational intervention had a positive impact on the reduction of pain and disability indices among the participants.

Comparison between pain and disability indices in the post-test intervention group compared to the post-test control group

According to the results depicted in Table 3, there was a significant reduction (P < 0.05) in the indices of disability and pain in the neck and shoulder areas among the participants in the post-test intervention group, due to the educational intervention, compared to the post-test control group. The specific reductions in the four questionnaires were Neck Disability Index (P = 0.005), Disabilities of the Arm, Shoulder, and Hand ((P = 0.043)), Visual Analog Scale for neck pain (P = 0.04), and Visual Analog Scale for shoulder pain (P = 0.006).

Comparison between pain and disability indices in the post-test control group compared to two months ago (pre-test control group)

Table 3 shows the post-test and pre-test results for the control group. According to the results, there was no significant change (P > 0.05) in the Neck Disability Index (P = 0.526) or the Disabilities of the Arm, Shoulder, and Hand Index (P = 0.311) in the control group, which did not receive the training, after two months, compared to before. Although the average Neck Disability Index may have increased, compared to two months ago, in the post-test control group, this change was not significant (P > 0.05); however, based on the Visual Analog Scale for the intensity of pain in both the neck (P = 0.001) and shoulder (P = 0.018), there was a significant reduction (P < 0.05) in intensity of pain.

Discussion

Considering the negative impacts of smartphone usage on users as had been reported by previous studies,[4] and the perceived needs for a study to address this problem, the current research aimed to train ergonomic usage of smartphone to young students. Students have often confronted with excessive usage and the negative consequences[8] associated with smartphones. The main goal was to increase awareness, leading to behavioral change, and consequently, the reduction of disability and pain indices in the two main purposed areas of body which were the neck and shoulder among the purposed population. The findings of the current research indicated the effectiveness of the Stanford University’s ergonomics guideline, after intervention in reducing disability and pain indices in the neck and shoulder areas among smartphone users. Hence, the current study has achieved its goal of addressing the ergonomic needs of smartphone users, particularly among young students. According to a similar study aimed at reducing the disability index of the shoulder among the purposed population of young students in the intervention group, compared to before education, the shoulder disability index had decreased from 37.88 up to 32.62 percent, with a relative difference of 13.88 percent,[44] while, in the current study, the same index had decreased from 8.88 up to 5.88, with a relative reduction of 33.18 percent in the disability index of the shoulder, arm, and hand, in addition to, the findings of the same study in Egypt regarded the DASH index in the post-test case group, compared to the post-test control group, which were 32.62 and 35.66, respectively, indicated a relative difference of 8.52 percent[44]; however, in the current study, this difference was 42.96 percent; furthermore, in the current study, the average of Neck Disability Index (NDI) in the pre-tests of intervention and control groups was 12.23 and 13.96 percent, respectively. A study in Turkey had reported the same index up to 12.89 percent among students,[32] which indicated a similarity in the status of the Neck Disability Index in Iran and Turkey, whereas in India, the same index was reported up to 30 percent among physiotherapy students.[33] The current study managed to reduce this index by a relative difference up to 28.29 percent in the post-case intervention, compared to the pre-test intervention group. The same reduction between both the post-control and post-intervention groups was 38.48 percent; moreover, the index of the Visual Analog Scale for neck pain severity in Turkey was reported up to 67.93 percent,[32] while the average of pain severity in the neck area, based on the Visual Analog Scale in the current study in both the pre-intervention and the pre-intervention groups, was 27.5 and 31.4 percent, respectively, among Iranian students. The current study managed to reduce this index by 33.63 percent between the post-control and post-intervention groups, and also by 42.06 percent between the pre-test and post-test in the intervention group. The findings of the current study depicted the greater severity of pain and discomfort in the neck area, compared to the shoulder which both findings were consistent with previous studies,[22,23]according to a global study in 2022 comparison between Iran with neck pain up to 1055.5 incidence per 100000, and other developed countries emphasized on the magnitude of ergonomic intervention for mitigation of neck and shoulder pain and disability, for instance, the condition of neck pain in Germany, Italy, and the United States is the same with 900–950 incidence per 100000, as well as, Spain and France, respectively, experienced (1000–1050, 800–850, 750–800 incidence per 100000), in 2017.[30] According to a study in 2024, during COVID-19, discomfort in neck was up to 43.3%, via smartphone usage among Iranian single individuals and students. This study emphasized on health professionals, in order to develop programs and recommendations for students,[45] the mentioned study approves the magnitude of setting an ergonomic program for education to purposed group, in fact it was conducted as an integral part of the aims of the current study. According to seven previous studies (controlled trials) depicted a significant reduction in VAS for neck pain and NDI, after stretch activities,[46,47] another study showed the influence of shoulder exercises on neck pain by NDI score. This study reduced NDI from 8.66 to 2.5 among intervention group.[48] The current study has been able to consider stretch activities as the third part of program, besides merging stretch activities, the elimination of static and repetitive strains injuries and postural improvement, for creating a comprehensive program, based on ergonomic principles [Table 1] which can be an innovative idea for the prevention of neck and shoulder pain and disability. Consequently, the findings of the current study demonstrated the effectiveness of the educational intervention, based on the ergonomic guidelines of Stanford University,[26,27,28,29,37,38,39] because the current study has significantly been able to reduce pain and disability indices in both neck and shoulder areas among intervention group compared to before educational intervention (P < 0.05); in addition to, the current study significantly reduced the same pain and disability indices in both neck and shoulder areas compared to post-test control group (P < 0.05).

Limitation and recommendation

One of the limitations and weaknesses of the current study, which included a pre-test and post-test group, is the comparison of post-test results with the pre-test. Based on the experience of the current study, the control group showed resistance to fill in the post-test questionnaires, unlike the pre-test, which led to a reduction in the number of individuals in the post-control group, while we asked and reminded participants of control group to fill in post-test questionnaires. During six times of reminders, during one month post-test, this phenomenon was less true for the intervention group, which had received the educational training over two months. Although the control group received the educational content, after completing the questionnaires as a symbol of appreciation and in line with ethical principles in research, another limitation was the time limitation of the educational intervention. It was possible that participants preferred to conduct some parts of program more than other parts, for example, educational program which was related to shoulder was possible to be conducted more than neck, and indeed we could not assess individuals’ desires. We could not follow the relationship between the change of behavior and the increasing level of knowledge, because the increasing knowledge which was able to bring about behavior change was crucial, not only the improvement of the level of knowledge among intervention group. Suggestions can be conducted in the future, such as developing a questionnaire, to determine the relationship between the level of awareness and the effective behavior change of users, developing software for training ergonomic principles as the alarms for employees, the effects of smartphone weight on shoulder, arm, and hand pain and disability. The usage of other methods for assessing neck and shoulder pain after training educational program, for instance, using electromyography, is observed.

Conclusion

The current study, via creating a comprehensive program and training it for ergonomic usage of smartphone among the purposed population, according to three concepts of ergonomic principles, including postural modification, the elimination of static postures (Micro-breaks), and stretch activities among young students, has been able to determine and prioritize pain and disability between the neck and shoulder, which, respectively, experienced the most pain and discomfort associated with awkward ergonomic usage of smartphone among both pre-test control and pre-test intervention groups, for priority of ergonomic intervention, based on body areas. Hence, via a valid and relevant educational intervention, the current study significantly reduced the severity of neck and shoulder pain and disability among post-test intervention group, compared to pre-test intervention group, as well as, the current study significantly reduced these mentioned indices among post-test intervention group, compared to post-test control group, according to the findings of four questioners (P < 0.05), which the findings approved the effectiveness of the Stanford University’s educational-ergonomic principles. According to the current study, the training and implementation of the Stanford University’s ergonomic principles can significantly reduce disability and pain indices in the neck and shoulder areas among smartphone users. Hence, this program to be trained to other smartphone users, including teachers, employees whom are stuck in behind the desk, and students, to prevent and alleviate disability and pain indices in both the neck and shoulder areas, during the usage of electronic devices like smartphones, is recommended.

Data availability

The data that support the findings of this study are available from the corresponding author, upon reasonable request.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.