{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T18:26:30Z","timestamp":1775759190138,"version":"3.50.1"},"reference-count":52,"publisher":"Public Library of Science (PLoS)","issue":"4","license":[{"start":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T00:00:00Z","timestamp":1775692800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000266","name":"Engineering and Physical Sciences Research Council","doi-asserted-by":"publisher","award":["EP\/T022523\/1"],"award-info":[{"award-number":["EP\/T022523\/1"]}],"id":[{"id":"10.13039\/501100000266","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000266","name":"Engineering and Physical Sciences Research Council","doi-asserted-by":"publisher","award":["EP\/M023281\/1"],"award-info":[{"award-number":["EP\/M023281\/1"]}],"id":[{"id":"10.13039\/501100000266","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:p>Whilst workload monitoring is key to managing performance and injury risk, effective strategies in tennis are not well-established. Mechanical work (external and internal components), measurable through markerless motion capture approaches, provides a novel way to quantify workload. To determine the suitability of this approach, this study investigated the association between mechanical work and acute neuromuscular fatigue. Fifteen tennis players completed a tennis-specific on-court fatiguing protocol interspersed with sprint tests. Peak sprint velocity (measure of acute neuromuscular fatigue) was correlated against mechanical work for each player. Pooled correlations (accounting for inter-individual differences) for total (external\u2009+\u2009internal) and external work, as well as external work estimated from centre of mass (CoM) proxies (pelvis and bounding box methods) were comparable, with values of \u22120.93 to \u22120.92. Although the calculated work done varied greatly between methods (~40% for pelvis method), these differences were systematic. All methods therefore appeared to provide an indication of individual players\u2019 workload (acute neuromuscular fatigue), despite the absolute values of the CoM proxy methods being inaccurate. Therefore, we recommend using the approximations only when monitoring an individual player in similar contexts. These findings present the markerless approach as a promising tool that could be implemented for non-invasive, on-court workload monitoring in tennis.<\/jats:p>","DOI":"10.1371\/journal.pone.0345913","type":"journal-article","created":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T17:31:09Z","timestamp":1775755869000},"page":"e0345913","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["Mechanical work derived using markerless motion capture provides a valid indication of acute neuromuscular fatigue in tennis"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-8613-1131","authenticated-orcid":true,"given":"Julie","family":"Emmerson","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8675-4684","authenticated-orcid":true,"given":"Laurie","family":"Needham","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1460-0085","authenticated-orcid":true,"given":"Sean","family":"Williams","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4973-6591","authenticated-orcid":true,"given":"Steffi L.","family":"Colyer","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"340","published-online":{"date-parts":[[2026,4,9]]},"reference":[{"issue":"8","key":"pone.0345913.ref001","doi-asserted-by":"crossref","first-page":"1215","DOI":"10.1080\/17461391.2020.1819435","article-title":"Association of acute and chronic workloads with injury risk in high-performance junior tennis players","volume":"21","author":"V Moreno-P\u00e9rez","year":"2021","journal-title":"Eur J Sport Sci"},{"issue":"11","key":"pone.0345913.ref002","doi-asserted-by":"crossref","first-page":"641","DOI":"10.1136\/bjsports-2016-095997","article-title":"It\u2019s not the destination, it\u2019s the \u201croad to load\u201d that matters: a tennis injury prevention perspective","volume":"50","author":"BM Pluim","year":"2016","journal-title":"Br J Sports Med"},{"issue":"3","key":"pone.0345913.ref003","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1177\/1941738109334274","article-title":"Risk factors for medical withdrawals in United States tennis association junior national tennis tournaments: a descriptive epidemiologic study","volume":"1","author":"NA Jayanthi","year":"2009","journal-title":"Sports Health"},{"issue":"3","key":"pone.0345913.ref004","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1177\/17479541221088836","article-title":"Practice and match workload of a female tennis player in two annual seasons: A single-case study","volume":"18","author":"A Filipcic","year":"2022","journal-title":"International Journal of Sports Science & Coaching"},{"issue":"5","key":"pone.0345913.ref005","doi-asserted-by":"crossref","first-page":"855","DOI":"10.1080\/24748668.2018.1525679","article-title":"Differences between running activity in tennis training and match-play","volume":"18","author":"C Gal\u00e9-Ansodi","year":"2018","journal-title":"International Journal of Performance Analysis in Sport"},{"issue":"3","key":"pone.0345913.ref006","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1080\/24748668.2017.1331572","article-title":"Movement analysis and metabolic profile of tennis match play: comparison between hard courts and clay courts","volume":"17","author":"M Ponzano","year":"2017","journal-title":"International Journal of Performance Analysis in Sport"},{"issue":"4","key":"pone.0345913.ref007","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1123\/ijspp.2021-0536","article-title":"Validity of the Training-Load Concept","volume":"17","author":"L Passfield","year":"2022","journal-title":"Int J Sports Physiol Perform"},{"issue":"2","key":"pone.0345913.ref008","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1123\/ijspp.2018-0935","article-title":"Internal and external training load: 15 years on","volume":"14","author":"FM Impellizzeri","year":"2019","journal-title":"Int J Sports Physiol Perform"},{"issue":"6","key":"pone.0345913.ref009","doi-asserted-by":"crossref","first-page":"1137","DOI":"10.1007\/s40279-020-01413-6","article-title":"Training Load and Injury: Causal Pathways and Future Directions","volume":"51","author":"JT Kalkhoven","year":"2021","journal-title":"Sports Med"},{"issue":"3","key":"pone.0345913.ref010","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1123\/jsr.2022-0044","article-title":"Injury Surveillance and Training Load Methods Used by Health Professionals in Tennis: An Online Multinational Survey","volume":"32","author":"DH M\u00e9ndez","year":"2022","journal-title":"J Sport Rehabil"},{"issue":"18","key":"pone.0345913.ref011","doi-asserted-by":"crossref","first-page":"1321","DOI":"10.1136\/bjsports-2017-097596","article-title":"Acute:chronic training loads in tennis: which metrics should we monitor?","volume":"51","author":"JD Vescovi","year":"2017","journal-title":"Br J Sports Med"},{"issue":"7","key":"pone.0345913.ref012","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0255339","article-title":"Validity and reliability of a novel monitoring sensor for the quantification of the hitting load in tennis","volume":"16","author":"V Had\u017ei\u0107","year":"2021","journal-title":"PLoS One"},{"issue":"1","key":"pone.0345913.ref013","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1177\/1747954118805278","article-title":"The Sony Smart Tennis Sensor accurately measures external workload in junior tennis players","volume":"14","author":"N Myers","year":"2018","journal-title":"International Journal of Sports Science & Coaching"},{"issue":"9","key":"pone.0345913.ref014","doi-asserted-by":"crossref","first-page":"1212","DOI":"10.1123\/ijspp.2016-0683","article-title":"Monitoring Hitting Load in Tennis Using Inertial Sensors and Machine Learning","volume":"12","author":"D Whiteside","year":"2017","journal-title":"Int J Sports Physiol Perform"},{"issue":"6","key":"pone.0345913.ref015","doi-asserted-by":"crossref","first-page":"756","DOI":"10.1123\/ijspp.2016-0259","article-title":"External Match Workloads During the First Week of Australian Open Tennis Competition","volume":"12","author":"D Whiteside","year":"2017","journal-title":"Int J Sports Physiol Perform"},{"issue":"3","key":"pone.0345913.ref016","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1123\/pes.2013-0195","article-title":"Running activity profile of adolescent tennis players during match play","volume":"26","author":"MW Hoppe","year":"2014","journal-title":"Pediatr Exerc Sci"},{"issue":"5","key":"pone.0345913.ref017","doi-asserted-by":"crossref","first-page":"523","DOI":"10.1016\/j.jsams.2009.07.003","article-title":"Accuracy and reliability of GPS devices for measurement of movement patterns in confined spaces for court-based sports","volume":"13","author":"R Duffield","year":"2010","journal-title":"J Sci Med Sport"},{"issue":"4","key":"pone.0345913.ref018","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0250549","article-title":"How far from the gold standard? Comparing the accuracy of a Local Position Measurement (LPM) system and a 15 Hz GPS to a laser for measuring acceleration and running speed during team sports","volume":"16","author":"K Fischer-Sonderegger","year":"2021","journal-title":"PLoS One"},{"issue":"3","key":"pone.0345913.ref019","doi-asserted-by":"crossref","first-page":"804","DOI":"10.1177\/1747954121990354","article-title":"\u201cYou come up with different theories every year\u201d: Practitioner perceptions of injury risk factors and player monitoring practices in elite men\u2019s domestic cricket","volume":"16","author":"L Goggins","year":"2021","journal-title":"International Journal of Sports Science & Coaching"},{"key":"pone.0345913.ref020","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1016\/j.procs.2015.08.060","author":"M Archana","year":"2015","journal-title":"Procedia Comput Sci"},{"key":"pone.0345913.ref021","first-page":"93","article-title":"Player tracking and stroke recognition in tennis video","author":"T Bloom","year":"2003","journal-title":"Proceedings of the APRS Workshop on Digital Image Computing. Brisbane, Australia"},{"issue":"2","key":"pone.0345913.ref022","first-page":"275","article-title":"Movement characteristics of elite tennis players on hard courts with respect to the direction of ground strokes","volume":"12","author":"R Mart\u00ednez-Gallego","year":"2013","journal-title":"J Sports Sci Med"},{"issue":"4","key":"pone.0345913.ref023","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1080\/02640414.2016.1165858","article-title":"Analysis of the distances covered and technical actions performed by professional tennis players during official matches","volume":"35","author":"TJC Pereira","year":"2017","journal-title":"J Sports Sci"},{"key":"pone.0345913.ref024","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1109\/ICECCS51672.2020.00014","article-title":"Deep Learning Application in Broadcast Tennis Video Annotation","author":"K Jiang","year":"2020","journal-title":"2020 25th International Conference on Engineering of Complex Computer Systems (ICECCS)"},{"issue":"2","key":"pone.0345913.ref025","doi-asserted-by":"crossref","first-page":"417","DOI":"10.1007\/s00421-023-05286-1","article-title":"Mechanical and metabolic power in accelerated running-Part II: team sports","volume":"124","author":"C Osgnach","year":"2024","journal-title":"Eur J Appl Physiol"},{"issue":"2","key":"pone.0345913.ref026","doi-asserted-by":"crossref","DOI":"10.1113\/jphysiol.1977.sp011866","article-title":"Mechanical work and efficiency in level walking and running","volume":"268","author":"GA Cavagna","year":"1977","journal-title":"J Physiol"},{"key":"pone.0345913.ref027","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1080\/02640414.2025.2555096","article-title":"Evaluation of a markerless motion capture system for measuring mechanical work during tennis strokes","author":"J Emmerson","year":"2025","journal-title":"J Sports Sci"},{"issue":"5","key":"pone.0345913.ref028","doi-asserted-by":"crossref","first-page":"445","DOI":"10.1016\/j.jsams.2021.10.013","article-title":"The \u201ctraining load\u201d construct: Why it is appropriate and scientific","volume":"25","author":"FM Impellizzeri","year":"2022","journal-title":"J Sci Med Sport"},{"issue":"17","key":"pone.0345913.ref029","doi-asserted-by":"crossref","first-page":"1030","DOI":"10.1136\/bjsports-2016-096581","article-title":"How much is too much? (Part 1) International Olympic Committee consensus statement on load in sport and risk of injury","volume":"50","author":"T Soligard","year":"2016","journal-title":"Br J Sports Med"},{"key":"pone.0345913.ref030","article-title":"Monitoring training load to understand fatigue in athletes","author":"SL Halson","year":"2014","journal-title":"Sports Med"},{"issue":"2","key":"pone.0345913.ref031","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1123\/ijspp.2021-0451","article-title":"Defining Training and Performance Caliber: A Participant Classification Framework","volume":"17","author":"AKA McKay","year":"2022","journal-title":"Int J Sports Physiol Perform"},{"issue":"9","key":"pone.0345913.ref032","doi-asserted-by":"crossref","first-page":"2522","DOI":"10.1519\/JSC.0000000000000912","article-title":"Comparison of the Capacity of Different Jump and Sprint Field Tests to Detect Neuromuscular Fatigue","volume":"29","author":"RJ Gathercole","year":"2015","journal-title":"J Strength Cond Res"},{"key":"pone.0345913.ref033","doi-asserted-by":"crossref","first-page":"111338","DOI":"10.1016\/j.jbiomech.2022.111338","article-title":"The development and evaluation of a fully automated markerless motion capture workflow","volume":"144","author":"L Needham","year":"2022","journal-title":"J Biomech"},{"key":"pone.0345913.ref034","unstructured":"OpenMMLab Pose Estimation Toolbox and Benchmark. 2020. https:\/\/github.com\/open-mmlab\/mmpose"},{"issue":"6","key":"pone.0345913.ref035","doi-asserted-by":"crossref","first-page":"1137","DOI":"10.1109\/TPAMI.2016.2577031","article-title":"Faster R-CNN: Towards Real-Time Object Detection with Region Proposal Networks","volume":"39","author":"S Ren","year":"2017","journal-title":"IEEE Trans Pattern Anal Mach Intell"},{"key":"pone.0345913.ref036","doi-asserted-by":"crossref","first-page":"5686","DOI":"10.1109\/CVPR.2019.00584","article-title":"Deep High-Resolution Representation Learning for Human Pose Estimation","author":"K Sun","year":"2019","journal-title":"2019 IEEE\/CVF Conference on Computer Vision and Pattern Recognition (CVPR). California, USA"},{"key":"pone.0345913.ref037","first-page":"7091","author":"F Zhang","year":"2020","journal-title":"Washington, USA"},{"key":"pone.0345913.ref038","first-page":"196","article-title":"Whole-body human pose estimation in the wild","author":"S Jin","year":"2020","journal-title":"Glasgow, UK"},{"issue":"11","key":"pone.0345913.ref039","doi-asserted-by":"crossref","first-page":"1940","DOI":"10.1109\/TBME.2007.901024","article-title":"OpenSim: open-source software to create and analyze dynamic simulations of movement","volume":"54","author":"SL Delp","year":"2007","journal-title":"IEEE Trans Biomed Eng"},{"issue":"9","key":"pone.0345913.ref040","doi-asserted-by":"crossref","first-page":"1223","DOI":"10.1016\/0021-9290(95)00178-6","article-title":"Adjustments to Zatsiorsky-Seluyanov\u2019s segment inertia parameters","volume":"29","author":"P de Leva","year":"1996","journal-title":"J Biomech"},{"key":"pone.0345913.ref041","first-page":"51","article-title":"A spreadsheet for combining outcomes from several subject groups","volume":"10","author":"WG Hopkins","year":"2006","journal-title":"Sportscience"},{"issue":"1","key":"pone.0345913.ref042","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1249\/MSS.0b013e31818cb278","article-title":"Progressive statistics for studies in sports medicine and exercise science","volume":"41","author":"WG Hopkins","year":"2009","journal-title":"Med Sci Sports Exerc"},{"issue":"11","key":"pone.0345913.ref043","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0293917","article-title":"Examination of 2D frontal and sagittal markerless motion capture: Implications for markerless applications","volume":"18","author":"L Wade","year":"2023","journal-title":"PLoS One"},{"issue":"11","key":"pone.0345913.ref044","doi-asserted-by":"crossref","first-page":"2135","DOI":"10.1007\/s40279-017-0714-2","article-title":"Training Load Monitoring in Team Sports: A Novel Framework Separating Physiological and Biomechanical Load-Adaptation Pathways","volume":"47","author":"J Vanrenterghem","year":"2017","journal-title":"Sports Med"},{"issue":"19","key":"pone.0345913.ref045","doi-asserted-by":"crossref","first-page":"1791","DOI":"10.1080\/02640414.2016.1139161","article-title":"Matchplay characteristics of Grand Slam tennis: implications for training and conditioning","volume":"34","author":"M Reid","year":"2016","journal-title":"J Sports Sci"},{"issue":"12","key":"pone.0345913.ref046","doi-asserted-by":"crossref","first-page":"1892","DOI":"10.1111\/sms.13520","article-title":"Comprehensive mechanical power analysis in sprint running acceleration","volume":"29","author":"G Pavei","year":"2019","journal-title":"Scand J Med Sci Sports"},{"issue":"1","key":"pone.0345913.ref047","doi-asserted-by":"crossref","first-page":"133","DOI":"10.52082\/jssm.2023.133","article-title":"From The Ground Up: Expert Perceptions of Lower Limb Activity Monitoring in Tennis","volume":"22","author":"M Lester","year":"2023","journal-title":"J Sports Sci Med"},{"issue":"1","key":"pone.0345913.ref048","first-page":"51","article-title":"Work smarter not harder: Mechanical work as a measure of athlete workload","volume":"42","author":"A Epp-Stobbe","year":"2024","journal-title":"ISBS Proceedings Archive"},{"issue":"1","key":"pone.0345913.ref049","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1123\/ijspp.2015-0712","article-title":"The Relationship Between Whole-Body External Loading and Body-Worn Accelerometry During Team-Sport Movements","volume":"12","author":"NJ Nedergaard","year":"2017","journal-title":"Int J Sports Physiol Perform"},{"key":"pone.0345913.ref050","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1123\/ijspp.2016-0499","article-title":"Player-tracking technology: half-full or half-empty glass?","volume":"12","author":"M Buchheit","year":"2017","journal-title":"Int J Sports Physiol Perform"},{"issue":"10","key":"pone.0345913.ref051","doi-asserted-by":"crossref","first-page":"3368","DOI":"10.3390\/s21103368","article-title":"Estimating Player Positions from Padel High-Angle Videos: Accuracy Comparison of Recent Computer Vision Methods","volume":"21","author":"M Javadiha","year":"2021","journal-title":"Sensors (Basel)"},{"key":"pone.0345913.ref052","doi-asserted-by":"crossref","first-page":"129","DOI":"10.3389\/fphys.2017.00129","article-title":"On the Estimation Accuracy of the 3D Body Center of Mass Trajectory during Human Locomotion: Inverse vs. Forward Dynamics","volume":"8","author":"G Pavei","year":"2017","journal-title":"Front Physiol"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0345913","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T17:31:17Z","timestamp":1775755877000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0345913"}},"subtitle":[],"editor":[{"given":"Daniel J.","family":"Glassbrook","sequence":"first","affiliation":[],"role":[{"role":"editor","vocabulary":"crossref"}]}],"short-title":[],"issued":{"date-parts":[[2026,4,9]]},"references-count":52,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2026,4,9]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0345913","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,9]]}}}