{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,4]],"date-time":"2026-03-04T04:46:06Z","timestamp":1772599566506,"version":"3.50.1"},"reference-count":32,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2024,7,31]],"date-time":"2024-07-31T00:00:00Z","timestamp":1722384000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Tai Chi is a Chinese martial art that provides an adaptive and accessible exercise for older adults with varying functional capacity. While Tai Chi is widely recommended for its physical benefits, wider adoption in at-home practice presents challenges for practitioners, as limited feedback may hamper learning. This study examined the feasibility of using a wearable sensor, combined with machine learning (ML) approaches, to automatically and objectively classify Tai Chi expertise. We hypothesized that the combination of wrist acceleration profiles with ML approaches would be able to accurately classify practitioners\u2019 Tai Chi expertise levels. Twelve older active Tai Chi practitioners were recruited for this study. The self-reported lifetime practice hours were used to identify subjects in low, medium, or highly experienced groups. Using 15 acceleration-derived features from a wearable sensor during a self-guided Tai Chi movement and 8 ML architectures, we found multiclass classification performance to range from 0.73 to 0.97 in accuracy and F1-score. Based on feature importance analysis, the top three features were found to each result in a 16\u201319% performance drop in accuracy. These findings suggest that wrist-wearable-based ML models may accurately classify practice-related changes in movement patterns, which may be helpful in quantifying progress in at-home exercises.<\/jats:p>","DOI":"10.3390\/s24154955","type":"journal-article","created":{"date-parts":[[2024,7,31]],"date-time":"2024-07-31T10:34:43Z","timestamp":1722422083000},"page":"4955","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Tai Chi Expertise Classification in Older Adults Using Wrist Wearables and Machine Learning"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7316-508X","authenticated-orcid":false,"given":"Yang","family":"Hu","sequence":"first","affiliation":[{"name":"Department of Kinesiology, College of Health and Human Science, San Jos\u00e9 State University, San Jose, CA 95129, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mengyue","family":"Huang","sequence":"additional","affiliation":[{"name":"School of Information Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0901-2828","authenticated-orcid":false,"given":"Jonathan","family":"Cerna","sequence":"additional","affiliation":[{"name":"Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9223-4546","authenticated-orcid":false,"given":"Rachneet","family":"Kaur","sequence":"additional","affiliation":[{"name":"Department of Industrial and Enterprise Systems Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3501-9508","authenticated-orcid":false,"given":"Manuel E.","family":"Hernandez","sequence":"additional","affiliation":[{"name":"Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA"},{"name":"Department of Biomedical and Translational Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA"},{"name":"Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA"},{"name":"Department of Kinesiology and Community Health, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA"},{"name":"Beckman Institute, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,7,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"418","DOI":"10.1177\/1559827610368777","article-title":"Clinical Implications of Tai Chi Interventions: A Review","volume":"4","author":"Zhu","year":"2010","journal-title":"Am. J. Lifestyle Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"397","DOI":"10.1136\/bjsports-2014-094388","article-title":"The effect of Tai Chi on four chronic conditions-cancer, osteoarthritis, heart failure and chronic obstructive pulmonary disease: A systematic review and meta-analyses","volume":"50","author":"Chen","year":"2016","journal-title":"Br. J. Sports Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"e188280","DOI":"10.1001\/jamanetworkopen.2018.8280","article-title":"Effectiveness of Tai Ji Quan vs Multimodal and Stretching Exercise Interventions for Reducing Injurious Falls in Older Adults at High Risk of Falling: Follow-up Analysis of a Randomized Clinical Trial","volume":"2","author":"Li","year":"2019","journal-title":"JAMA Netw. Open"},{"key":"ref_4","unstructured":"Stevens, J.A., and Burns, E.R. (2015). A CDC Compendium of Effective Fall Interventions: What Works for Community-Dwelling Older Adults, Technical Report."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"445","DOI":"10.1123\/jpah.5.3.445","article-title":"Tai Chi: Moving for better balance\u2014Development of a community-based falls prevention program","volume":"5","author":"Li","year":"2008","journal-title":"J. Phys. Act. Health"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Bian, Y., Yang, C., Guan, D., Xiao, S., Gao, F., Shen, C., and Meng, X. (2016, January 7\u201312). Effects of Pedagogical Agent\u2019s Personality and Emotional Feedback Strategy on Chinese Students\u2019 Learning Experiences and Performance: A Study Based on Virtual Tai Chi Training Studio. Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems (CHI\u201916), New York, NY, USA.","DOI":"10.1145\/2858036.2858351"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"641","DOI":"10.1080\/17434440.2016.1198694","article-title":"Wearable inertial sensors for human movement analysis","volume":"13","author":"Iosa","year":"2016","journal-title":"Expert Rev. Med. Devices"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.jesf.2020.05.003","article-title":"Augmented reality-assisted training with selected Tai-Chi movements improves balance control and increases lower limb muscle strength in older adults: A prospective randomized trial","volume":"18","author":"Chen","year":"2020","journal-title":"J. Exerc. Sci. Fit."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1016\/j.smhl.2018.07.021","article-title":"Virtual Tai-Chi System: A smart-connected modality for rehabilitation","volume":"9","author":"Liang","year":"2018","journal-title":"Smart Health"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"712","DOI":"10.1016\/j.procs.2020.06.147","article-title":"A real-time interactive tai chi learning system based on vr and motion capture technology","volume":"174","author":"Liu","year":"2020","journal-title":"Procedia Comput. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Ho, T.J., Chou, K.T., Li, C.H., Kuo, B.C., and Huang, T.C. (2018). Quantitative Motion Analysis of Tai Chi Chuan: The Upper Extremity Movement. Biomed. Res. Int., 2018.","DOI":"10.1155\/2018\/2538765"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"453","DOI":"10.1080\/14763140701491674","article-title":"Biomechanics of Tai Chi: A review","volume":"6","author":"Hong","year":"2007","journal-title":"Sport. Biomech."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Shen, S., Wang, H., and Roy Choudhury, R. (2016, January 26\u201330). I am a Smartwatch and I can Track my User\u2019s Arm. Proceedings of the 14th Annual International Conference on Mobile Systems, Applications, and Services (MobiSys\u201916), New York, NY, USA.","DOI":"10.1145\/2906388.2906407"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Okita, S., Yakunin, R., Korrapati, J., Ibrahim, M., Schwerz de Lucena, S., Chan, V., and Reinkensmeyer, D.J. (2023). Counting Finger and Wrist Movements Using Only a Wrist-Worn, Inertial Measurement Unit: Toward Practical Wearable Sensing for Hand-Related Healthcare Applications. Sensors, 23.","DOI":"10.3390\/s23125690"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"2192","DOI":"10.1161\/STROKEAHA.121.036578","article-title":"Tailored Sitting Tai Chi Program for Subacute Stroke Survivors: A Randomized Controlled Trial","volume":"53","author":"Zhao","year":"2023","journal-title":"Stroke"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1186\/s12984-023-01203-x","article-title":"Characteristics of corticomuscular coupling during wheelchair Tai Chi in patients with spinal cord injury","volume":"20","author":"Zu","year":"2023","journal-title":"J. Neuroeng. Rehabil."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1111\/cpf.12127","article-title":"A universal, accurate intensity-based classification of different physical activities using raw data of accelerometer","volume":"35","author":"Vasankari","year":"2015","journal-title":"Clin. Physiol. Funct. Imaging"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/j.smhs.2022.06.002","article-title":"Biomechanics analysis of seven Tai Chi movements","volume":"4","author":"Law","year":"2022","journal-title":"Sport. Med. Health Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1080\/15438627.2017.1393753","article-title":"Kinetics of the lower limb during two typical Tai Chi movements in the elderly","volume":"26","author":"Li","year":"2018","journal-title":"Res. Sport. Med."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1080\/15438627.2014.881819","article-title":"The Temporospatial and Kinematic Characteristics of Typical Tai Chi Movements: Repulse Monkey and Wave-hand in Cloud","volume":"22","author":"Law","year":"2014","journal-title":"Res. Sport. Med."},{"key":"ref_21","first-page":"M629","article-title":"Tai chi practice reduces movement force variability for seniors","volume":"54","author":"Yan","year":"1999","journal-title":"J. Gerontol. Ser. Biomed. Sci. Med. Sci."},{"key":"ref_22","unstructured":"Chung, W.Y., Purwar, A., and Sharma, A. (2008, January 20\u201325). Frequency domain approach for activity classification using accelerometer. Proceedings of the 2008 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Vancouver, BC, Canada."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"152","DOI":"10.1016\/j.jesf.2024.02.004","article-title":"Tai Chi counteracts age-related somatosensation and postural control declines among older adults","volume":"22","author":"Zhang","year":"2024","journal-title":"J. Exerc. Sci. Fit."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"616","DOI":"10.1123\/mc.2021-0022","article-title":"Effects of Eight Methods and Five Steps of Tai Chi Practice on Balance Control Among Older Adults","volume":"25","author":"Hu","year":"2021","journal-title":"Mot. Control"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1016\/j.jelekin.2005.12.005","article-title":"Muscle activation profiles about the knee during Tai-Chi stepping movement compared to the normal gait step","volume":"17","author":"Tseng","year":"2007","journal-title":"J. Electromyogr. Kinesiol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"488","DOI":"10.1016\/j.tics.2019.03.007","article-title":"Visceral Signals Shape Brain Dynamics and Cognition","volume":"23","author":"Azzalini","year":"2019","journal-title":"Trends Cogn. Sci."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"e26763","DOI":"10.2196\/26763","article-title":"Assessing Physicians\u2019 Recall Bias of Work Hours With a Mobile App: Interview and App-Recorded Data Comparison","volume":"23","author":"Wang","year":"2021","journal-title":"J. Med. Internet Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"695","DOI":"10.1002\/acp.903","article-title":"Memory bias in the recall of pre-exam anxiety: The influence of self-enhancement","volume":"17","author":"Dewhurst","year":"2003","journal-title":"Appl. Cogn. Psychol."},{"key":"ref_29","first-page":"217","article-title":"Twenty-four-hour recall, knowledge-attitude-practice questionnaires, and direct observations of sanitary practices: A comparative study","volume":"65","author":"Stanton","year":"1987","journal-title":"Bull. World Health Organ."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1893","DOI":"10.1056\/NEJM199212313272701","article-title":"Discrepancy between Self-Reported and Actual Caloric Intake and Exercise in Obese Subjects","volume":"327","author":"Lichtman","year":"1992","journal-title":"N. Engl. J. Med."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"2529","DOI":"10.1007\/s12671-022-01977-6","article-title":"Dose\u2013response Relationship of Reported Lifetime Meditation Practice with Mental Health and Wellbeing: A Cross-sectional Study","volume":"13","author":"Bowles","year":"2022","journal-title":"Mindfulness"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"23337214231185912","DOI":"10.1177\/23337214231185912","article-title":"Mind-Body Practice and Family Caregivers\u2019 Subjective Well-Being: Findings From the Midlife in the United States (MIDUS) Study","volume":"9","author":"Bhattacharyya","year":"2023","journal-title":"Gerontol. Geriatr. Med."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/15\/4955\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T15:27:05Z","timestamp":1760110025000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/15\/4955"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,7,31]]},"references-count":32,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2024,8]]}},"alternative-id":["s24154955"],"URL":"https:\/\/doi.org\/10.3390\/s24154955","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,7,31]]}}}