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Inappropriate sitting posture leads to musculoskeletal problems and is reported to be linked with the individual's confidence. This study explores the importance of recommended sitting posture on student, health, and sleep.
70 volunteer adolescent students aged 18–26 years were enrolled in this study. Instructions and sensitization lectures about the study were conducted and obtained informed consent. The students were asked to wear an upper scapular brace from 8.30 a.m. to 4.30 p.m. daily/31 days and advised to maintain the optimal sitting posture as per occupational health guidelines. The effect of the upper scapular brace and optimal sitting on posture from the various body angles were measured at sitting and standing. Pittsburgh Sleep Quality Index (PSQI), Simple lifestyle indicator questionnaires (SLIQ), Happiness index (HI) responses was collected and analysed. Measured multitasking tests and anthropometric variables like Height, Weight, and BMI before and after the intervention and effect sizes (Cohen's d) was calculated. Used an alpha level (P < 0.05) to define statistical significance.
Significant differences (trivial or minor effect) were observed on PQSI, Height, BMI, back, hip, and knee angles only on sitting position following an intervention.
The findings of this study propose that wearing an upper scapular brace may assist in maintaining the optimal posture by influencing the back, hip, and knee angle and improves the quality of sleep. However, no significant difference among cognition and other measured indexes was observed.
Among the general population, students are at higher risk of poor posture with sedentary lifestyles and poor posture, especially in courses with higher academic demands. The majority of their days were spent in sitting posture. Prolonged sitting with poor posture among students, sedentary adults, or professionals, may affect their cognitive ability
and sleep quality due to poor posture that causes muscle imbalances, tension, fatigue, and eventually leads to musculoskeletal pain during sleep or daytime. An association between upright posture and mobility with different cognitive processes and underlying neural mechanisms remains unclear.
However, only a few studies have dealt with the relationship between cognition and body posture concerning to students. This study aims to evaluate the recommended sitting posture and proper posture maintenance with the help of the scapular upper brace influences on cognition, behavior, body alignment, and quality of sleep in the student population.
Posture is the position assumed by the body in both static positions (static posture) and movement (dynamic posture). Humans were designed to be upright, and our bodily functions are best when we are in that position. However, due to the extensive usage of automation, technology, and electronic gadgets, the time spent was more than 8 h per day in sitting.
However, studies and reports on the effects of proper posture maintenance during sitting and walking on overall behavior and psychological health remain unproven or not adequately focused and result in a lack of scientific evidence. Studies on prolonged unusual sitting posture may be associated with chronic diseases
and severely impact on psychological health and cognition, leading to anxiety and depression. In addition to the time spent sitting in common sedentary behaviors such as smartphones, TV, video games, digital toys, office work, internet, sitting in automobiles, transportation, and communications, improper sitting during these instances may have a high degree of harm on developmental health, well-being, and behavior.
The improper seating/slouching at the desk in classrooms, lecture halls, libraries, and at home for hours at a time restricts the students, children, and adolescents' adequate physical movements. It forces them to adapt their postural adjustments, including the micro and macro motions. If incorrect postures persist over time, it becomes a habit at an early age. Individuals and students maintaining those incorrect postures may adapt and consider them comfortable, leading to fatigue and deformation
in the near or later stages of life. This study focuses more on explaining the importance of the recommended sitting posture on health and related parameters in adult students' behaviour and health.
The present interventional study was carried out in the Department of Physiology, AIIMS, Mangalagiri, Andhra Pradesh, India. The study was initiated after the Institutional Ethical Committee (AIIMS/MG/IEC/2021-22/101) approval. The study protocol was explained in detail to the participating students of AIIMS Mangalagiri, India, and informed written consent was obtained. Only students volunteer of the age group of 18–26 years of both gender were allowed to enroll in this study. Before the study initiation, the medical history and medical examination were carried out, and students were selected based on inclusion and exclusion criteria. Following the screening, only 70 students have met the criteria. Following post-intervention, three students withdrew from the study, and only the data from 67 students comprising 34 male and 33 female data were utilized for further analysis of the study.
3. Schematic layout of this study
Intervention: The selected participants, based on the criteria were sensitized, demonstrated, and instructed to wear posture upper back brace (given individually) along with proper sitting posture guidelines to follow as per recommendations from Canadian Centre for Occupational Health and Safety Guidelines
throughout for 31 days (from 8.30 a.m. to 4.30 p.m.). We emphasized the study participants maintain the correct posture wherever they tend or want to sit, even at their home and hostel during the non-wearing time.
Variables measured: The Height was measured using a wall-mounted stadiometer (VM Electronics Hardware Ltd) accurate to the nearest 0.1 cm and Weight using the digital weighing machine (Charter Electronic Co. Ltd. Taichung, Taiwan 2013) accurate to the nearest 0.1 kg. BMI was calculated using BMI = weight (kg)/height (m2).
Pittsburgh sleeps quality index (PSQI) for quality of sleep with Cronbach's alpha value of 0.83, lifestyle and health questionnaires alpha value of 0.82
The various body angles measurement could give us details about the joint's compensation/alignment based on the principle of photogrammetry from the photographs using the mobile-based app (Posture corrector). The participant's pictures (lateral and frontal view) were taken in their natural posture while sitting and standing. Three persons were asked to take the same person's picture using the mobiles of the same app after the instruction of how to take the picture. However, they were blinded about the objective of the study. The height of the mobile camera was adjusted based on the subject's height using the mobile stand. Various angles mentioned above were calculated from the participant picture at the level of (Face, neck, back, hip and knee angle). It was carried out similarly after the intervention as well and compared. Before the analysis, the angles measurement and pictures taken were supervised, cross-checked, and confirmed by fellow investigators.
The various body angles that could give us details about the joint's compensation/alignment after the intervention were measured based on the principle of photogrammetry from the photographs. The measured body angles as defined by the various kinetic points was given below (Fig. 1: A and B).
The sample size was calculated based on the previous similar study with less duration and students number. Expecting 20% improvement in sleep quality with 5% alpha error, 80% power and 10% lost to follow for two side hypothesis testing the sample size was calculated to 70 using n-Master software 2.0.
Statistical Analysis: Paired student t-test to assess the mean difference between the baseline and post-intervention variables. The magnitude of the significant changes before and after the interventions were analysed using Cohen's effect sizes small effect (d = 0.2), medium effect (d = 0.5), and large effect (d = 0.8). The data distribution was assessed using the Kolmogorov-Smirnov test. All the data were analysed using SPSS software version 20.0 (SPSS Inc., Chicago, USA). Statistical significance between the groups was determined by paired Student t-test, and the significance level was fixed at p < 0.05.
Out of 70 adolescent students aged between 18 and 26 recruited for this study, only 67 participants' data after post-intervention were found to be completed, and analyses were carried out. The analysis was done using the paired t-test, excluding the 3 participants' data with missing variables withdrawn from this study.
Table: 1 presents the comparison of PSQI, SLIQ, HIQ, and other outcome variables (Multitasking test, Weight (Kg), Height (in cm), BMI (kg/m2) between baseline and after intervention (n = 67). The data obtained after the intervention shows that there is a significant difference observed only in PQSI (P = 0.00) (d = 0.4), Height (P = 0.01) (d = 0.2), and BMI (P = 0.03) (d = 0.2) compared to baseline. No significant differences were observed among the other variables and questionnaires such as SLIQ, HIQ, Multitasking, Weight between baseline compared to intervention.
Table: 1comparison of PSQI, SLIQ, HIQ, and other outcome variables between baseline and after intervention (n = 67).
Variables and Questionnaires
Mean ± SD
Mean ± SD
Effect size Cohen's D
4.42 ± 2.31
5.60 ± 2.23
6.87 ± 1.39
6.94 ± 1.38
134.16 ± 31.47
135.43 ± 24.11
Multitasking Score (task switch cost)
174.50 ± 114.84
157.97 ± 89.59
66.67 ± 14.24
66.32 ± 13.7
Height (in cm)
166.47 ± 8.66
166.93 ± 8.64
24.10 ± 4.21
23.72 ± 3.97
Data was expressed in Mean ± SD. The mean differences between the groups were analysed using student's paired t-test. PQSI- Pittsburg sleep quality index Questionnaire; SLIQ-Simple Lifestyle Indicator Questionnaire; HIQ- Happiness index Questionnaire; BMI- body mass index. P value less than .05 is considered to be significant. *P < 0.05, **P ≤ 0.01 (2 tailed). Cohen's effect sizes: small effect (d = 0.2), medium effect (d = 0.5), and large effect (d = 0.8).
Table: 2 represents the various angle measurements at baseline and after intervention at sitting and standing. The study findings show that following posture intervention, there is a significant difference was observed only in the Back angle (P = 0.03) (d = 0.2), Hip angle (P = 0.00) (d = 0.4), and Knee angle (P = 0.05) (d = 0.2) and not on the Face angle, Neck angle at sitting position. However, there are no marked significant differences observed between baseline and after intervention in all the various angle measurements, including (Face angle (P = 0.30), Neck angle (P = 0.35), Back angle (P = 0.47), Hip angle (P = 0.06), Knee angle (P = 0.69) at standing.
Table: 2Comparison of various joint angle between baseline and after intervention (n = 67).
Various angle measurement's
Mean ± SD
Mean ± SD
Effect size Cohen's D
6.15 ± 3.81
6.49 ± 4.31
11.84 ± 6.84
12.03 ± 6.16
109.10 ± 8.62
111.66 ± 9.05
99.06 ± 9.09
96.04 ± 8.22
87.30 ± 10.95
84.81 ± 9.53
5.09 ± 3.66
5.57 ± 4.28
11.58 ± 7.00
10.76 ± 6.53
118.16 ± 7.66
118.52 ± 9.06
173.78 ± 3.93
174.70 ± 4.12
167.27 ± 5.99
167.57 ± 4.55
Data was expressed in Mean ± SD. The mean difference between the groups were analysed using student's paired t-test. P value less than 0.05 is considered to be significant. *P < 0.05, **P ≤ 0.01 (2 tailed). Cohen's effect sizes: small effect (d = 0.2), medium effect (d = 0.5), and large effect (d = 0.8).
Prolonged sitting in the office and usage of electronic gadgets is unavoidable in the flexor dominant society, leading to improper posture maintenance. In this study, following the scapular brace intervention, irrespective of the types of chairs used by the participants, we observed the significant changes in angles expressed at the back, hip and knee levels only at sitting posture and not at standing. The effect could be based on the ''regional interdependence'' where interventions directed at one body region will often have effects at remote and seemingly unrelated areas.
These checkpoints will get altered due to the prolonged faulty posture and eventually cause pain in the head, neck, and jaw; the possible reason could be the structural adaptations at ligaments and muscle (either shortens or lengthens).
discomfort, and accidents. According to the Canadian centre for occupational health and safety guidelines, good posture is outlined to keep the joints such as hips, knees, and ankles open slightly (>90°) and to keep the head aligned with the erected and upright spine (Fig. 2) with supported back. Hands, wrists, and forearms straight, parallel to the floor.
Usually, sitting posture has more pressure load on the back than standing due to the spinopelvic imbalance that may result in chronic lumbar back pain. However, only the correct sitting posture with support on any type of chair causes minimal changes to Lumbar lordosis, and sacral slope compared withstanding.
The increase in back angle could help bring the back towards optimal alignment, which may alleviate pressure on the intradiscal and reduce forward bend in the back. Brace application also reported decreasing the forward shoulder angle with the influence on lower, middle, and upper trapezius, which was evidenced using EMG.
As per the standard guidelines, the recommended hip angle is > 90o.10 In this study, the posture brace may assist the participants in maintaining the optimal back angle in sitting posture that has inadvertently influenced their hip angle significantly. Following posture intervention, the decreased hip angle could also be due to the altered muscle imbalances and joint position. The individual optimum posture was chiefly based on their daily routine and habits that usually involve complex interactions between bones, joints, connective tissue, skeletal muscles, and the central and peripheral nervous system, both central and peripheral.
The changes at single kinetic points influence the angle at the proximal and distal. The changes at the knee angle were also observed as significantly reduced.
Regarding sleep, the findings indicate that scapular brace intervention significantly influences the quality of sleep among the students. Change in sleeping posture is well known to affect sleeping quality.
In this study, we have not studied the sleeping posture. However, we hypothesize that the change in sitting posture using ergonomic chairs or braces to support the spine and posture may lead to changes in sleeping posture and eventually lead to better sleep. The bracing idea in this study acts as a correction and supports the optimum posture during prolonged sitting and not immobilization. Another possible reason could be the reduced back pain or attenuated intradiscal pressure and muscular strain in the optimal sitting position. However, the research data is insufficient, and sensor-based nonwearable devices application and technology advances application on maintaining the self-posture with continuous feedback among the larger population remains unstudied.
Postural changes and the maintenance of postural stability have affected many aspects of cognition.
The task switching cost was recorded before and after the brace intervention to analyze the possibility of brace intervention as a stressor to the participants that could affect their cognitive control and related processes using concurrent manual task-switching cost test using PsyTool kit online software. After the intervention, results from the multitasking task switch cost found no marked changes compared to baseline, and the lack of similar scientific studies in the literature was noticed. Although, improper posture maintenance unconsciously is also unavoidable.
Hence, we hypothesize that a wearable scapular upper brace may assist the individual in maintaining a normal posture, thereby resulting in improved joint angles.
It is also to be notable and needs to be considered that this study includes both male and female participants, which may typically have innate differences in their spine as a whole or individual vertebra (gender-specific) irrespective of the study findings. There are no significant gender differences were observed in all the measured variables.
Throughout this study duration, the participants were instructed to maintain their posture according to the standard guidelines to keep the head in line with the body during the non-brace wearing time. The observed changes in the height may be associated with the scapular posture brace application on improved shoulder posture and scapular muscle activity.
Our results demonstrated that the scapular upper brace &, maintaining correct sitting posture (as per Guidelines) with appropriate joint alignment, improves the posture, as evidenced by the change in back angle, knee angle, and hip angle during sitting posture and sleep quality following the intervention. This could be due to proprioceptive feedback and assistance from the brace with the alteration in joint angles position.
However, there is no improvement in joint position during the standing posture, which needs to be explored further.
The sample size of the present study is only moderate, and the study was not assessed the sleep quality parameters when recruiting the volunteers. Since it is a single-arm intervention study, no control group was added separately. After the recruitment, it was noticed that the average participants BMI mean (23.97 ± 4.24) was found to be above the regular participants; their waist or abdominal fat level influence on posture was not included in this study. The postural instability in obese individuals with increased lordosis due to abdominal fat and poor integration may affect the intervention outcomes by causing discomfort to the wearable braces. Finally, the COVID-19 lockdown then and there further complicated the data collection and follow-up of the study.
31-days of postural maintenance (assistance using upper scapular brace) and appropriate sitting posture irrespective of the type of chair among the sedentary participants may support the optimal posture by influencing the body angles at back, hip, knee level and sleep quality. No marked changes were observed on cognition. The observed changes was trivial or minor following the short-term intervention, however provides an insight for future research and explains the importance of posture maintenance, especially for the individuals confined to the sitting position over a long period of time.
Declaration of competing interest
We are very grateful for the funding provided by the Indian Council of Medical Research (ICMR) under the Short Term Studentship (STS) Project to conduct this study [Reference ID: 2020-00641 ]. This article also would like to extend the sincere thanks to the Department of Physiology, AIIMS Mangalagiri, Andhrapradesh, India, and volunteers for participation and providing the necessary support.
Effect of sitting posture on spine joint angles and forces.
in: Proceedings of the 6th International Conference on Rehabilitation Engineering & Assistive Technology. 1–4. 2012