{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,17]],"date-time":"2026-01-17T20:00:58Z","timestamp":1768680058286,"version":"3.49.0"},"reference-count":46,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2022,4,27]],"date-time":"2022-04-27T00:00:00Z","timestamp":1651017600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Union","award":["N\u00b0 754354"],"award-info":[{"award-number":["N\u00b0 754354"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Swimming coaches provide regular timed and technical feedback to swimmers and guide them efficiently in training sessions. Due to the complexity of swimmers\u2019 performance, which is not visible in qualitative observation, quantitative and objective performance evaluation can better assist the coach in this regard. Inertial measurement units (IMUs) are used in swimming for objective performance evaluation. In this study, we propose a new performance evaluation feedback (SmartSwim) using IMU and investigate its effects on the swimmer\u2019s weekly progress. Measurements were conducted each week with 15 competitive swimmers for 10 weeks using a Sacrum IMU. The SmartSwim report included a comprehensive representation of performance based on goal metrics of each phase extracted from the IMU signals. The swimmers were divided into two groups: the experimental and control groups. The SmartSwim report for each swimmer in the experimental group was given to the coach, who used it to adjust the training accordingly. The results showed that the experimental group outperformed the control group when comparing each swimmer, each session and the whole sessions. At the level of each individual, more members of the experimental group showed significant downward trend of average lap time (Mann-Kendall trend test, 95% confidence level). While comparing the sessions, the experimental group showed significantly lower lap time than the control group from the sixth session onwards (p-value &lt; 0.05 from t-test). Considering all sessions, the experimental group showed significantly higher progress, lower average lap time, and more consistent records (Mann-Whitney U test at 95% confidence level) than the control group. This study demonstrated that SmartSwim can assist coaching by quantitatively assessing swimmers\u2019 performance, leading to more efficient training.<\/jats:p>","DOI":"10.3390\/s22093356","type":"journal-article","created":{"date-parts":[[2022,4,27]],"date-time":"2022-04-27T22:20:20Z","timestamp":1651098020000},"page":"3356","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["SmartSwim, a Novel IMU-Based Coaching Assistance"],"prefix":"10.3390","volume":"22","author":[{"given":"Mahdi","family":"Hamidi Rad","sequence":"first","affiliation":[{"name":"Laboratory of Movement Analysis and Measurement, EPFL, CH-1015 Lausanne, Switzerland"}]},{"given":"Vincent","family":"Gremeaux","sequence":"additional","affiliation":[{"name":"Institute of Sport Sciences, University of Lausanne, CH-1015 Lausanne, Switzerland"},{"name":"Sport Medicine Unit, Division of Physical Medicine and Rehabilitation, Swiss Olympic Medical Center, Lausanne University Hospital, CH-1011 Lausanne, Switzerland"}]},{"given":"Fabien","family":"Mass\u00e9","sequence":"additional","affiliation":[{"name":"Gait Up S.A., CH-1020 Lausanne, Switzerland"}]},{"given":"Farzin","family":"Dadashi","sequence":"additional","affiliation":[{"name":"Huma Therapeutics Ltd., London SW1P 4QP, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6582-5375","authenticated-orcid":false,"given":"Kamiar","family":"Aminian","sequence":"additional","affiliation":[{"name":"Laboratory of Movement Analysis and Measurement, EPFL, CH-1015 Lausanne, Switzerland"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"185","DOI":"10.3758\/BF03196276","article-title":"Principles Derived Form the Studies of Simple Motor Skills Do Not Generalize to Complex Skill Learning","volume":"9","author":"Wulf","year":"2002","journal-title":"Psychon. Bull. Rev."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"21","DOI":"10.3758\/s13423-012-0333-8","article-title":"Augmented Visual, Auditory, Haptic, and Multimodal Feedback in Motor Learning: A Review","volume":"20","author":"Sigrist","year":"2013","journal-title":"Psychon. Bull. Rev."},{"key":"ref_3","first-page":"41","article-title":"The Effect of Real Time Feedback on Swimming Technique","volume":"2","author":"Jefferies","year":"2012","journal-title":"J. Int. Soc. Swim. Coach."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"997","DOI":"10.1080\/02640414.2015.1085074","article-title":"Analysis of Swimming Performance: Perceptions and Practices of US-Based Swimming Coaches","volume":"34","author":"Mooney","year":"2016","journal-title":"J. Sports Sci."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1491","DOI":"10.1097\/00005768-199711000-00016","article-title":"Technique and Energy Losses in Front Crawl Swimming","volume":"29","author":"Berger","year":"1997","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1007\/s00421-003-0919-y","article-title":"Energy Balance of Human Locomotion in Water","volume":"90","author":"Pendergast","year":"2003","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref_7","unstructured":"Seifert, L., Chollet, D., and Mujika, I. (2011). World Book of Swimming: From Science to Performance, Nova Science Publishers."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"447","DOI":"10.1080\/02640419508732261","article-title":"Estimating Propulsive Forces in Swimming from Three-Dimensional Kinematic Data","volume":"13","author":"Payton","year":"1995","journal-title":"J. Sports Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"737","DOI":"10.1080\/02640410400021955","article-title":"Bilateral Inter-Arm Coordination in Freestyle Swimming: Effect of Skill Level and Swimming Speed","volume":"23","author":"Nikodelis","year":"2005","journal-title":"J. Sports Sci."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Payton, C.J., and Adrian Burden, E. (2017). Biomechanical Evaluation of Movement in Sport and Exercise: The British Association of Sport and Exercise Sciences Guide, Routledge.","DOI":"10.4324\/9780203095546"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1260\/1747-9541.4.1.139","article-title":"A Comparison of Video and Accelerometer Based Approaches Applied to Performance Monitoring in Swimming","volume":"4","author":"Callaway","year":"2010","journal-title":"Int. J. Sports Sci. Coach."},{"key":"ref_12","first-page":"53","article-title":"Effects of Two Types of Biomechanical Bio-Feedback on Crawl Performance","volume":"48","author":"Chollet","year":"1992","journal-title":"Biomech. Med. Swim. Swim. Sci. VI"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Ukai, Y., and Rekimoto, J. (2013, January 7\u20138). Swimoid: A Swim Support System Using an Underwater Buddy Robot. Proceedings of the 4th Augmented Human International Conference, Stuttgart, Germany.","DOI":"10.1145\/2459236.2459265"},{"key":"ref_14","first-page":"350","article-title":"A Multi-Sensor System for Monitoring the Performance of Elite Swimmers","volume":"222","author":"Bindel","year":"2012","journal-title":"Commun. Comput. Inf. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Ramos F\u00e9lix, E., da Silva, H.P., Olstad, B.H., Cabri, J., and Lobato Correia, P. (2019). SwimBIT: A Novel Approach to Stroke Analysis During Swim Training Based on Attitude and Heading Reference System (AHRS). Sports, 7.","DOI":"10.3390\/sports7110238"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/j.proeng.2013.07.067","article-title":"Determining Maximum Push-off Velocity in Swimming Using Accelerometers","volume":"60","author":"Stamm","year":"2013","journal-title":"Procedia Eng."},{"key":"ref_17","first-page":"3","article-title":"Characterizing the Swimming Tumble Turn Using Acceleration Data","volume":"226","author":"Slawson","year":"2012","journal-title":"Proc. Inst. Mech. Eng. Part P J. Sport. Eng. Technol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1251","DOI":"10.1080\/02640414.2013.778420","article-title":"Automatic Front-Crawl Temporal Phase Detection Using Adaptive Filtering of Inertial Signals","volume":"31","author":"Dadashi","year":"2013","journal-title":"J. Sports Sci."},{"key":"ref_19","unstructured":"B\u00e4chlin, M., F\u00f6rster, K., and Tr\u00f6ster, G. (October, January 30). SwimMaster: A Wearable Assistant for Swimmer. Proceedings of the 11th International Conference on Ubiquitous Computing\u2014Ubicomp\u201909, Orlando, FL, USA."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Rocha, L.A., and Correia, J.H. (2006, January 11\u201314). Wearable Sensor Network for Body Kinematics Monitoring. Proceedings of the 10th IEEE International Symposium on Wearable Computers, Montreux, Switzerland.","DOI":"10.1109\/ISWC.2006.286364"},{"key":"ref_21","unstructured":"Silva, A.S., Salazar, A.J., Correia, M.F., and Borges, C.M. (2011, January 26\u201329). WIMU: Wearable Inertial Monitoring Unit\u2014A MEMS-Based Device for Swimming Performance Analysis. Proceedings of the International Conference on Biomedical Electronics and Devices\u2014BIODEVICES, Rome, Italy."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Ehab, M., Mohamed, H., Ahmed, M., Hammad, M., Elmasry, N., and Atia, A. (2020, January 25\u201329). ISwimCoach: A Smart Coach Guiding System for Assisting Swimmers Free Style Strokes: ISwimCoach. Proceedings of the ICMI 2020 Companion\u2014Companion Publication of the 2020 International Conference on Multimodal Interaction, Virtual Event.","DOI":"10.1145\/3395035.3425314"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Mangin, M., Valade, A., Costes, A., Bouillod, A., Acco, P., and Soto-Romero, G. (2015, January 15\u201317). An Instrumented Glove for Swimming Performance Monitoring. Proceedings of the 3rd International Congress on Sport Sciences Research and Technology Support\u2014icSPORTS, Lisbon, Portugal.","DOI":"10.5220\/0005609100530058"},{"key":"ref_24","first-page":"1","article-title":"A Novel Macro-Micro Approach for Swimming Analysis in Main Swimming Techniques Using IMU Sensors","volume":"8","author":"Gremeaux","year":"2021","journal-title":"Front. Bioeng. Biotechnol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"793302","DOI":"10.3389\/fbioe.2021.793302","article-title":"Swimming Phase-Based Performance Evaluation Using a Single IMU in Main Swimming Techniques","volume":"9","author":"Aminian","year":"2021","journal-title":"Front. Bioeng. Biotechnol."},{"key":"ref_26","unstructured":"Kendall, M.G. (1995). Rank Correlation Methods, Hafner Publishing Company."},{"key":"ref_27","unstructured":"Gilbert, R.O. (1987). Statistical Methods for Environmental Pollution Monitoring, John Wiley & Sons."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1080\/01621459.1967.10482916","article-title":"On the Kolmogorov-Smirnov Test for Normality with Mean and Variance Unknown","volume":"62","author":"Lilliefors","year":"1967","journal-title":"J. Am. Stat. Assoc."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"540","DOI":"10.4097\/kjae.2015.68.6.540","article-title":"T Test as a Parametric Statistic","volume":"68","author":"Kim","year":"2015","journal-title":"Korean J. Anesthesiol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"13","DOI":"10.20982\/tqmp.04.1.p013","article-title":"The Mann-Whitney U: A Test for Assessing Whether Two Independent Samples Come from the Same Distribution","volume":"4","author":"Nachar","year":"2008","journal-title":"Tutor. Quant. Methods Psychol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1214\/aoms\/1177730491","article-title":"On a Test of Whether One of Two Random Variables Is Stochastically Larger than the Other","volume":"18","author":"Mann","year":"1947","journal-title":"Ann. Math. Stat."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1080\/1462394042000270718","article-title":"Reflective Practice and the Origins of Elite Coaching Knowledge","volume":"5","author":"Irwin","year":"2004","journal-title":"Reflective Pract."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1405","DOI":"10.1080\/02640414.2015.1114134","article-title":"Front-Crawl Stroke Descriptors Variability Assessment for Skill Characterization","volume":"34","author":"Dadashi","year":"2016","journal-title":"J. Sports Sci."},{"key":"ref_34","first-page":"129","article-title":"Analysis of the Interactions between Breathing and Arm Actions in the Front Crawl","volume":"40","author":"Lerda","year":"2001","journal-title":"J. Hum. Mov. Stud."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1055\/s-2007-1021282","article-title":"A Simple Method for Determining Critical Speed as Swimming Fatigue Threshold in Competitive Swimming","volume":"13","author":"Wakayoshi","year":"1992","journal-title":"Int. J. Sports Med."},{"key":"ref_36","first-page":"666","article-title":"Toward an Explanation of Continuous Improvement in Expert Athletes: The Role of Consciousness in Deliberate Practice","volume":"46","author":"Toner","year":"2015","journal-title":"Int. J. Sport Psychol"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"997","DOI":"10.1097\/00005768-200005000-00018","article-title":"Consistency of Swimming Performance within and between Competitions","volume":"32","author":"Stewart","year":"2000","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"92","DOI":"10.1177\/1747954116684390","article-title":"Feedback for Coaches: Who Coaches the Coach?","volume":"12","author":"Nash","year":"2017","journal-title":"Int. J. Sport. Sci. Coach."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"373","DOI":"10.2165\/00007256-199519060-00002","article-title":"Seasonal Variation in Fitness Parameters in Competitive Athletes","volume":"19","author":"Koutedakis","year":"1995","journal-title":"Sport. Med."},{"key":"ref_40","unstructured":"Bielec, G., Makar, P., and Foli\u00f1ski, P. (2008). Biomechanical Effects of Application of the Technique Exercises in Young Swimmer Training. SWIMMING II, Wydawnictwo AWF."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1080\/1612197X.2006.9671790","article-title":"Effect of a Psychological Skills Training Program on Swimming Performance and Positive Psychological Development","volume":"4","author":"Sheard","year":"2006","journal-title":"Int. J. Sport Exerc. Psychol."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"360","DOI":"10.1123\/ijsnem.2014-0015","article-title":"Nutrition for Swimming","volume":"24","author":"Shaw","year":"2014","journal-title":"Int. J. Sport Nutr. Exerc. Metab."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"732","DOI":"10.1080\/02640414.2014.962574","article-title":"Wearable Inertial Sensors in Swimming Motion Analysis: A Systematic Review","volume":"33","author":"Vannozzi","year":"2015","journal-title":"J. Sports Sci."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"125","DOI":"10.2478\/hukin-2013-0052","article-title":"Competitive Performance, Training Load and Physiological Responses during Tapering in Young Swimmers","volume":"38","author":"Toubekis","year":"2013","journal-title":"J. Hum. Kinet."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1111\/1464-0597.00108","article-title":"The Effect of Mental Training with Biofeedback on the Performance of Young Swimmers","volume":"51","author":"Dreshman","year":"2002","journal-title":"Appl. Psychol."},{"key":"ref_46","first-page":"440","article-title":"The Impact of the High Level of Intensity Training Process on the Performance and Recovery of Young Swimmers at the National Level","volume":"21","author":"Gussakov","year":"2021","journal-title":"J. Phys. Educ. Sport"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/9\/3356\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:02:12Z","timestamp":1760137332000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/9\/3356"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,4,27]]},"references-count":46,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2022,5]]}},"alternative-id":["s22093356"],"URL":"https:\/\/doi.org\/10.3390\/s22093356","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,4,27]]}}}