{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T13:16:45Z","timestamp":1778678205969,"version":"3.51.4"},"reference-count":72,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2021,3,15]],"date-time":"2021-03-15T00:00:00Z","timestamp":1615766400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["SFRH\/BD\/147608\/2019"],"award-info":[{"award-number":["SFRH\/BD\/147608\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/04045\/2020"],"award-info":[{"award-number":["UIDB\/04045\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/50008\/2020"],"award-info":[{"award-number":["UIDB\/50008\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/00742\/2020"],"award-info":[{"award-number":["UIDB\/00742\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Smartphone sensors have often been proposed as pervasive measurement systems to assess mobility in older adults due to their ease of use and low-cost. This study analyzes a smartphone-based application\u2019s validity and reliability to quantify temporal variables during the single sit-to-stand test with institutionalized older adults. Forty older adults (20 women and 20 men; 78.9 \u00b1 8.6 years) volunteered to participate in this study. All participants performed the single sit-to-stand test. Each sit-to-stand repetition was performed after an acoustic signal was emitted by the smartphone app. All data were acquired simultaneously with a smartphone and a digital video camera. The measured temporal variables were stand-up time and total time. The relative reliability and systematic bias inter-device were assessed using the intraclass correlation coefficient (ICC) and Bland-Altman plots. In contrast, absolute reliability was assessed using the standard error of measurement and coefficient of variation (CV). Inter-device concurrent validity was assessed through correlation analysis. The absolute percent error (APE) and the accuracy were also calculated. The results showed excellent reliability (ICC = 0.92\u20130.97; CV = 1.85\u20133.03) and very strong relationships inter-devices for the stand-up time (r = 0.94) and the total time (r = 0.98). The APE was lower than 6%, and the accuracy was higher than 94%. Based on our data, the findings suggest that the smartphone application is valid and reliable to collect the stand-up time and total time during the single sit-to-stand test with older adults.<\/jats:p>","DOI":"10.3390\/s21062050","type":"journal-article","created":{"date-parts":[[2021,3,15]],"date-time":"2021-03-15T02:51:48Z","timestamp":1615776708000},"page":"2050","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":20,"title":["An Experimental Study on the Validity and Reliability of a Smartphone Application to Acquire Temporal Variables during the Single Sit-to-Stand Test with Older Adults"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6653-0616","authenticated-orcid":false,"given":"Diogo Lu\u00eds","family":"Marques","sequence":"first","affiliation":[{"name":"Department of Sport Sciences, University of Beira Interior, 6201-001 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9283-312X","authenticated-orcid":false,"given":"Henrique Pereira","family":"Neiva","sequence":"additional","affiliation":[{"name":"Department of Sport Sciences, University of Beira Interior, 6201-001 Covilh\u00e3, Portugal"},{"name":"Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, 6201-001 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3394-6762","authenticated-orcid":false,"given":"Ivan Miguel","family":"Pires","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, Universidade da Beira Interior, 6200-001 Covilh\u00e3, Portugal"},{"name":"Computer Science Department, Polytechnic Institute of Viseu, 3504-510 Viseu, Portugal"},{"name":"Health Sciences Research Unit: Nursing, School of Health, Polytechnic Institute of Viseu, 3504-510 Viseu, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7664-0168","authenticated-orcid":false,"given":"Eftim","family":"Zdravevski","sequence":"additional","affiliation":[{"name":"Faculty of Computer Science and Engineering, University Ss Cyril and Methodius, 1000 Skopje, North Macedonia"}]},{"given":"Martin","family":"Mihajlov","sequence":"additional","affiliation":[{"name":"Laboratory for Open Systems and Networks, Jozef Stefan Institute, 1000 Ljubljana, Slovenia"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3195-3168","authenticated-orcid":false,"given":"Nuno M.","family":"Garcia","sequence":"additional","affiliation":[{"name":"Instituto de Telecomunica\u00e7\u00f5es, Universidade da Beira Interior, 6200-001 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8882-4965","authenticated-orcid":false,"given":"Juan Diego","family":"Ruiz-C\u00e1rdenas","sequence":"additional","affiliation":[{"name":"Physiotherapy Department, Faculty of Health Sciences, Catholic University of Murcia, 30107 Murcia, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2351-3047","authenticated-orcid":false,"given":"Daniel Almeida","family":"Marinho","sequence":"additional","affiliation":[{"name":"Department of Sport Sciences, University of Beira Interior, 6201-001 Covilh\u00e3, Portugal"},{"name":"Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, 6201-001 Covilh\u00e3, Portugal"}]},{"given":"M\u00e1rio Cardoso","family":"Marques","sequence":"additional","affiliation":[{"name":"Department of Sport Sciences, University of Beira Interior, 6201-001 Covilh\u00e3, Portugal"},{"name":"Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, 6201-001 Covilh\u00e3, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,15]]},"reference":[{"key":"ref_1","first-page":"80","article-title":"Global Population Aging: Facts, Challenges, Solutions & Perspectives","volume":"144","author":"Bloom","year":"2015","journal-title":"Chall. 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