{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T18:02:24Z","timestamp":1780682544600,"version":"3.54.1"},"reference-count":52,"publisher":"Public Library of Science (PLoS)","issue":"6","license":[{"start":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T00:00:00Z","timestamp":1780617600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Science and Technology Development Agency (NSTDA) of Thailand"},{"name":"Walailak University Graduate Research Fund","award":["CGS-RF-2023\/04"],"award-info":[{"award-number":["CGS-RF-2023\/04"]}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:p>\n                    Carrying backpacks daily imposes a physical burden on school-aged children, raising increasing public concern. This study compared the physiological responses and head\u2013neck posture of primary school students when carrying traditional versus modified bags. Thirty-two public primary school students aged 7\u201312 years participated. Physiological measures included heart rate (HR), oxygen saturation (SpO\u2082), blood pressure, and respiratory rate (RR). Head and neck tilt angles and forward head posture were assessed using photogrammetry and Kinovea software. Participants walked at a natural pace (1.1\u20131.3 m\/s) along an 8-meter walkway for five minutes under five conditions: no bag, bilateral traditional bag, unilateral traditional bag, bilateral modified bag, and unilateral modified bag. Backpack design showed significant main effects on heart rate (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009=\u20090.001, \u03b7p\u00b2\u2009=\u20090.316), respiratory rate (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009=\u20090.007, \u03b7p\u00b2\u2009=\u20090.214), systolic blood pressure (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009&lt;\u20090.001, \u03b7p\u00b2\u2009=\u20090.387), and diastolic blood pressure (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009=\u20090.002, \u03b7p\u00b2\u2009=\u20090.279), with higher values in the traditional condition (e.g., HR 95.94\u2009\u00b1\u20092.26 bpm; RR 31.59\u2009\u00b1\u20090.86 breaths\/min; systolic 108.33\u2009\u00b1\u20091.30 mmHg; diastolic 78.05\u2009\u00b1\u20091.64 mmHg). Carrying method affected HR (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009=\u20090.014, \u03b7p\u00b2\u2009=\u20090.178), with higher values during unilateral use. No interaction effects were found for physiological variables (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009&gt;\u20090.05). SpO\u2082 remained stable (98.78\u201399.47%). For posture, significant effects of design were observed for neck tilt (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009&lt;\u20090.001, \u03b7p\u00b2\u2009=\u20090.350), head tilt (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009=\u20090.001, \u03b7p\u00b2\u2009=\u20090.324), and forward head posture (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009&lt;\u20090.001, \u03b7p\u00b2\u2009=\u20090.335). The traditional backpack produced smaller neck tilt (49.75\u00b0\u2009\u00b1\u20091.05\u00b0) but greater head tilt (78.60\u00b0\u2009\u00b1\u20091.56\u00b0) and forward head posture (8.68\u2009\u00b1\u20094.59 cm). Unilateral carrying increased head tilt (77.83\u00b0\u2009\u00b1\u20091.56\u00b0,\n                    <jats:italic>p<\/jats:italic>\n                    \u2009=\u20090.021). Interaction effects were found for neck and head tilt (\n                    <jats:italic>p<\/jats:italic>\n                    \u2009&lt;\u20090.05). The modified backpack reduces physiological strain and improves postural alignment, particularly under unilateral carrying, while bilateral use minimizes asymmetrical loading.\n                  <\/jats:p>","DOI":"10.1371\/journal.pone.0350165","type":"journal-article","created":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T17:23:26Z","timestamp":1780680206000},"page":"e0350165","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Evaluating physiological responses and forward head-neck posture in primary students in Thailand when carrying modified and traditional backpacks"],"prefix":"10.1371","volume":"21","author":[{"given":"Jittaporn","family":"Mongkonkansai","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6894-8955","authenticated-orcid":true,"given":"Udomsak","family":"Narkkul","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3551-4039","authenticated-orcid":true,"given":"Chadapa","family":"Rungruangbaiyok","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4826-9474","authenticated-orcid":true,"given":"Chuchard","family":"Punsawad","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,6,5]]},"reference":[{"issue":"1","key":"pone.0350165.ref001","first-page":"222","article-title":"A study of school bag weight and back pain among primary school children in Al-Ahsa, Saudi Arabia","volume":"6","author":"SA Al-Saleem","year":"2016","journal-title":"Epidemiology (Sunnyvale)"},{"issue":"5","key":"pone.0350165.ref002","doi-asserted-by":"crossref","first-page":"512","DOI":"10.1097\/BPO.0b013e31817d8143","article-title":"Asymmetric loads and pain associated with backpack carrying by children","volume":"28","author":"BR Macias","year":"2008","journal-title":"J Pediatr Orthop"},{"key":"pone.0350165.ref003","doi-asserted-by":"crossref","first-page":"103166","DOI":"10.1016\/j.ergon.2021.103166","article-title":"School backpack design: A systematic review and a summary of design items","volume":"84","author":"JCN Lee","year":"2021","journal-title":"Int J Ind Ergon"},{"issue":"11","key":"pone.0350165.ref004","doi-asserted-by":"crossref","first-page":"2529","DOI":"10.3390\/ijerph15112529","article-title":"The impact of backpack loads on school children: A critical narrative review","volume":"15","author":"M Perrone","year":"2018","journal-title":"Int J Environ Res Public Health"},{"issue":"4","key":"pone.0350165.ref005","doi-asserted-by":"crossref","first-page":"533","DOI":"10.4103\/ijcm.ijcm_80_22","article-title":"Impact of educational intervention in reducing the weight of school bags in selected school children","volume":"48","author":"SK Saini","year":"2023","journal-title":"Indian J Community Med"},{"issue":"1","key":"pone.0350165.ref006","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1080\/00140130903389050","article-title":"Short-term effects of backpack load placement on spine deformation and repositioning error in schoolchildren","volume":"53","author":"DHK Chow","year":"2010","journal-title":"Ergonomics"},{"issue":"5","key":"pone.0350165.ref007","doi-asserted-by":"crossref","first-page":"720","DOI":"10.1080\/00140139.2017.1413213","article-title":"Effects of backpack load and positioning on nonlinear gait features in young adults","volume":"61","author":"FB Rodrigues","year":"2018","journal-title":"Ergonomics"},{"key":"pone.0350165.ref008","doi-asserted-by":"crossref","first-page":"1045666","DOI":"10.3389\/fped.2022.1045666","article-title":"Neglected problem: Influence of school bag on lumbar segment in children","volume":"10","author":"M Bajin","year":"2022","journal-title":"Front Pediatr"},{"key":"pone.0350165.ref009","doi-asserted-by":"crossref","first-page":"687","DOI":"10.4102\/ajod.v10i0.687","article-title":"Altered cervical posture kinematics imposed by heavy school backpack loading: A literature synopsis (2009-2019)","volume":"10","author":"TJ Ellapen","year":"2021","journal-title":"Afr J Disabil"},{"issue":"1","key":"pone.0350165.ref010","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1097\/PEP.0b013e31827ab2f7","article-title":"Postural compensations and subjective complaints due to backpack loads and wear time in schoolchildren","volume":"25","author":"F Kistner","year":"2013","journal-title":"Pediatr Phys Ther"},{"key":"pone.0350165.ref011","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1515\/bhk-2018-0010","article-title":"Postural balance and neck angle changes in school children while carrying a traditional backpack versus a double-sided bag","volume":"10","author":"DM Mosaad","year":"2018","journal-title":"Biomed Hum Kinet"},{"issue":"4","key":"pone.0350165.ref012","first-page":"809","article-title":"Ergonomic factors of school bags and their adaptation to the weight of students","volume":"65","author":"A Alami","year":"2020","journal-title":"Work"},{"issue":"1","key":"pone.0350165.ref013","first-page":"175","article-title":"Ergonomics evaluation of school bags in Tehran female primary school children","volume":"56","author":"S Mohammadi","year":"2017","journal-title":"Work"},{"key":"pone.0350165.ref014","doi-asserted-by":"crossref","first-page":"753","DOI":"10.1016\/j.ergon.2014.08.004","article-title":"An ergonomics evaluation of the vibration backpack harness system in walking","volume":"44","author":"Z Tang","year":"2014","journal-title":"Int J Ind Ergon"},{"key":"pone.0350165.ref015","first-page":"168","article-title":"One-shoulder carrying school backpack strongly affects gait swing phase and pelvic tilt: A case study","volume":"91","author":"V Presta","year":"2020","journal-title":"Acta Biomed"},{"key":"pone.0350165.ref016","doi-asserted-by":"crossref","first-page":"103095","DOI":"10.1016\/j.ergon.2021.103095","article-title":"Influence of school bag loads and carrying methods on body strain among young male students","volume":"82","author":"YL Chen","year":"2021","journal-title":"Int J Ind Ergon"},{"issue":"4","key":"pone.0350165.ref017","first-page":"455","article-title":"The effect of shoulder strap width and load placement on shoulder-backpack interface pressure","volume":"58","author":"S Golriz","year":"2017","journal-title":"Work"},{"issue":"6","key":"pone.0350165.ref018","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1097\/01.phm.0000219149.14010.d0","article-title":"Changes in posture and perceived exertion in adolescents wearing backpacks with and without abdominal supports","volume":"85","author":"AB Marsh","year":"2006","journal-title":"Am J Phys Med Rehabil"},{"key":"pone.0350165.ref019","doi-asserted-by":"crossref","first-page":"1437126","DOI":"10.1155\/2020\/1437126","article-title":"Development and experimental verification of an ergonomic backpack","volume":"2020","author":"MZ Ramadan","year":"2020","journal-title":"Biomed Res Int"},{"issue":"2","key":"pone.0350165.ref020","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1016\/j.jbiomech.2008.10.012","article-title":"Characterization of the mechanical properties of backpacks and their influence on the energetics of walking","volume":"42","author":"M Foissac","year":"2009","journal-title":"J Biomech"},{"key":"pone.0350165.ref021","doi-asserted-by":"crossref","DOI":"10.2196\/55361","article-title":"The accuracy of pulse oxygen saturation, heart rate, blood pressure, and respiratory rate raised by a contactless telehealth portal: Validation study","volume":"8","author":"J Gerald Dcruz","year":"2024","journal-title":"JMIR Form Res"},{"issue":"2","key":"pone.0350165.ref022","first-page":"539","article-title":"Evaluation of an ergonomically designed schoolbag: Heart rate variability and body discomfort rating","volume":"72","author":"MZ Ramadan","year":"2022","journal-title":"Work"},{"key":"pone.0350165.ref023","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1007\/s11332-008-0060-8","article-title":"Effect of carrying school backpacks on cardio-respiratory changes in adolescent students","volume":"4","author":"H Daneshmandi","year":"2008","journal-title":"Sport Sci Health"},{"key":"pone.0350165.ref024","first-page":"206","article-title":"Statistical method in biological assay","volume":"7","author":"O Heinisch","year":"1965","journal-title":"Biom Z"},{"key":"pone.0350165.ref025","unstructured":"Basic human body measurements for technological design \u2014 Part 1: Body measurement definitions and landmarks. 2017. https:\/\/www.iso.org\/obp\/ui\/#iso:std:iso:7250:-1:ed-2:v1:en"},{"key":"pone.0350165.ref026","article-title":"An analysis of biomechanical and anthropometric parameters on classroom furniture design","volume":"7","author":"M Tunay","year":"2008","journal-title":"Afr J Biotechnol"},{"issue":"1","key":"pone.0350165.ref027","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1007\/s13534-019-00097-w","article-title":"Current progress of photoplethysmography and SPO2 for health monitoring","volume":"9","author":"T Tamura","year":"2019","journal-title":"Biomed Eng Lett"},{"key":"pone.0350165.ref028","doi-asserted-by":"crossref","first-page":"04036","DOI":"10.7189\/jogh.12.04036","article-title":"Success and time implications of SpO2 measurement through pulse oximetry among hospitalised children in rural Bangladesh: Variability by various device-, provider- and patient-related factors","volume":"12","author":"AE Rahman","year":"2022","journal-title":"J Glob Health"},{"issue":"4","key":"pone.0350165.ref029","doi-asserted-by":"crossref","DOI":"10.1161\/CIR.0000000000000803","article-title":"Self-measured blood pressure monitoring at home: A Joint Policy Statement From the American Heart Association and American Medical Association","volume":"142","author":"D Shimbo","year":"2020","journal-title":"Circulation"},{"issue":"5","key":"pone.0350165.ref030","doi-asserted-by":"crossref","DOI":"10.1161\/HYP.0000000000000087","article-title":"Measurement of blood pressure in humans: A scientific statement from the American Heart Association","volume":"73","author":"P Muntner","year":"2019","journal-title":"Hypertension"},{"key":"pone.0350165.ref031","unstructured":"High Blood Pressure. https:\/\/www.heart.org\/en\/health-topics\/high-blood-pressure. Accessed 2023 October 31."},{"key":"pone.0350165.ref032","unstructured":"World Health Organization. Pocket book of hospital care for children: guidelines for the management of common childhood illnesses. Geneva: World Health Organization. 2013."},{"issue":"8","key":"pone.0350165.ref033","doi-asserted-by":"crossref","first-page":"2700","DOI":"10.3390\/s18082700","article-title":"Continuous monitoring of respiratory rate in emergency admissions: Evaluation of the RespiraSense\u2122 Sensor in acute care compared to the industry standard and gold standard","volume":"18","author":"CP Subbe","year":"2018","journal-title":"Sensors (Basel)"},{"issue":"1","key":"pone.0350165.ref034","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1016\/j.annemergmed.2004.06.016","article-title":"The vexatious vital: Neither clinical measurements by nurses nor an electronic monitor provides accurate measurements of respiratory rate in triage","volume":"45","author":"PB Lovett","year":"2005","journal-title":"Ann Emerg Med"},{"key":"pone.0350165.ref035","doi-asserted-by":"crossref","first-page":"595","DOI":"10.1016\/j.pmn.2023.04.005","article-title":"Self-management exercises intervention on text neck syndrome among university students using smartphones","volume":"24","author":"F Sarraf","year":"2023","journal-title":"Pain Management Nursing: Official Journal of the American Society of Pain Management Nurses"},{"issue":"12","key":"pone.0350165.ref036","doi-asserted-by":"crossref","first-page":"2892","DOI":"10.1007\/s00586-015-4143-3","article-title":"Photographic measurement of head and cervical posture when viewing mobile phone: A pilot study","volume":"24","author":"X Guan","year":"2015","journal-title":"Eur Spine J"},{"key":"pone.0350165.ref037","first-page":"62","article-title":"The effect of duration of smartphone use on head and shoulders posture of young adults aged 20-35 years","volume":"7","author":"AS Masoumi","year":"2019","journal-title":"Iran J Ergon"},{"issue":"3","key":"pone.0350165.ref038","doi-asserted-by":"crossref","first-page":"254","DOI":"10.1016\/S0966-6362(00)00055-2","article-title":"Changes in gait patterns in 10-year-old boys with increasing loads when walking on a treadmill","volume":"11","author":"Y Hong","year":"2000","journal-title":"Gait Posture"},{"issue":"2","key":"pone.0350165.ref039","doi-asserted-by":"crossref","first-page":"199","DOI":"10.1016\/j.apergo.2004.10.007","article-title":"The effect of simulated school load carriage configurations on shoulder strap tension forces and shoulder interface pressure","volume":"36","author":"HW Mackie","year":"2005","journal-title":"Appl Ergon"},{"key":"pone.0350165.ref040","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1186\/1748-7161-2-8","article-title":"Postural effects of symmetrical and asymmetrical loads on the spines of schoolchildren","volume":"2","author":"S Negrini","year":"2007","journal-title":"Scoliosis"},{"issue":"1","key":"pone.0350165.ref041","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1080\/00140139.2019.1677944","article-title":"Cervical spine joint loading with neck flexion","volume":"63","author":"JM Barrett","year":"2020","journal-title":"Ergonomics"},{"key":"pone.0350165.ref042","article-title":"Effect of backpack weight on cervical angle in school going children","volume":"11","author":"S Kulshrestha","year":"2017","journal-title":"Int J Clin Ski"},{"issue":"3","key":"pone.0350165.ref043","doi-asserted-by":"crossref","first-page":"1076","DOI":"10.4103\/jfmpc.jfmpc_367_18","article-title":"Effect of backpack loading on cervical and sagittal shoulder posture in standing and after dynamic activity in school going children","volume":"8","author":"NP Vaghela","year":"2019","journal-title":"J Family Med Prim Care"},{"issue":"4","key":"pone.0350165.ref044","doi-asserted-by":"crossref","first-page":"713","DOI":"10.1016\/S0278-5919(20)30480-4","article-title":"Overuse injuries to tendons and apophyses in children and adolescents","volume":"11","author":"LJ Micheli","year":"1992","journal-title":"Clin Sports Med"},{"issue":"21","key":"pone.0350165.ref045","doi-asserted-by":"crossref","first-page":"4104","DOI":"10.3390\/ijerph16214104","article-title":"Comparison between the physiological responses and subjective ratings of a group of male students to three backpack designs","volume":"16","author":"MZ Ramadan","year":"2019","journal-title":"Int J Environ Res Public Health"},{"key":"pone.0350165.ref046","doi-asserted-by":"crossref","first-page":"784","DOI":"10.1080\/0014013042000193264","article-title":"Effect of load position on physiological and perceptual responses during load carriage with an internal frame backpack","volume":"47","author":"KJ Stuempfle","year":"2004","journal-title":"Ergonomics"},{"issue":"9","key":"pone.0350165.ref047","doi-asserted-by":"crossref","first-page":"2437","DOI":"10.1589\/jpts.28.2437","article-title":"Effect of backpack shoulder straps length on cervical posture and upper trapezius pressure pain threshold","volume":"28","author":"OR Abdelraouf","year":"2016","journal-title":"J Phys Ther Sci"},{"key":"pone.0350165.ref048","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/j.jbiomech.2018.05.016","article-title":"Effects of an improved biomechanical backpack strap design on load transfer to the shoulder soft tissues","volume":"76","author":"A Hadid","year":"2018","journal-title":"J Biomech"},{"issue":"6","key":"pone.0350165.ref049","doi-asserted-by":"crossref","first-page":"642","DOI":"10.1080\/00140130500070921","article-title":"The effect of backpack load on the gait of normal adolescent girls","volume":"48","author":"DHK Chow","year":"2005","journal-title":"Ergonomics"},{"key":"pone.0350165.ref050","doi-asserted-by":"crossref","first-page":"5532012","DOI":"10.1155\/2021\/5532012","article-title":"The influence of external additional loading on the muscle activity and ground reaction forces during gait","volume":"2021","author":"B Zagrodny","year":"2021","journal-title":"Appl Bionics 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