{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T15:16:39Z","timestamp":1783350999691,"version":"3.54.6"},"reference-count":35,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T00:00:00Z","timestamp":1783296000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: The muscle synergy framework suggests that the central nervous system simplifies hand motor control by recruiting coordinated groups of muscles. However, the organization of these synergies across functional grasp types representative of activities of daily living remains incompletely understood. This study aimed to characterize muscle synergies across functional grasps and identify shared coordination patterns relevant for neuromuscular assessment. Methods: Muscle synergies were analysed in 26 healthy participants using a publicly available surface electromyography dataset. Five representative functional grasp types were selected, (cylindrical, lateral pinch, lumbrical, oblique, and tridigital pinch) and synergies were extracted using non-negative matrix factorization. Results: Four to five muscle synergies accounted for more than 90% of EMG variance across all grasp types. Despite grasp-specific differences, a consistent set of shared synergies was identified across conditions, explaining 92.5% of the total variance and being flexibly modulated depending on task demands. Extensor-related components showed a particularly consistent contribution across grasps. Conclusions: Functional hand grasping relies on a compact and reusable set of muscle synergies that are flexibly adapted to task demands. These findings support a modular organization of neuromuscular control and provide normative references that may be useful for the assessment of altered motor control in neuromuscular disorders, with potential applications in neurorehabilitation and assistive technologies.<\/jats:p>","DOI":"10.3390\/jcm15135268","type":"journal-article","created":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T13:43:14Z","timestamp":1783345394000},"page":"5268","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Characterization of Muscle Synergies During Activities of Daily Living Using Surface EMG: A Functional Reference for Neuromuscular Assessment"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1473-4008","authenticated-orcid":false,"given":"Ana","family":"Poveda-Garc\u00eda","sequence":"first","affiliation":[{"name":"Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"},{"name":"Research Group Participation, Roles, Occupations and Activities for the Transformation of Communities, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5840-541X","authenticated-orcid":false,"given":"Elisabet","family":"Huertas-Hoyas","sequence":"additional","affiliation":[{"name":"Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"},{"name":"Research Group Participation, Roles, Occupations and Activities for the Transformation of Communities, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6437-6758","authenticated-orcid":false,"given":"Cristina","family":"Garc\u00eda-Bravo","sequence":"additional","affiliation":[{"name":"Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"},{"name":"Research Group Participation, Roles, Occupations and Activities for the Transformation of Communities, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"},{"name":"Research Group of Humanities and Qualitative Research in Health Science, Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3586-2623","authenticated-orcid":false,"given":"Jorge","family":"P\u00e9rez-Corrales","sequence":"additional","affiliation":[{"name":"Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"},{"name":"Research Group of Humanities and Qualitative Research in Health Science, Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5677-6188","authenticated-orcid":false,"given":"M\u00aa Pilar","family":"Rodr\u00edguez-P\u00e9rez","sequence":"additional","affiliation":[{"name":"Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"},{"name":"Research Group Participation, Roles, Occupations and Activities for the Transformation of Communities, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-2049-9325","authenticated-orcid":false,"given":"Elisa","family":"Bull\u00f3n-Benito","sequence":"additional","affiliation":[{"name":"Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, 28922 Alcorc\u00f3n, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,6]]},"reference":[{"key":"ref_1","unstructured":"Bernstein, N.A. (1967). The Co-Ordination and Regulation of Movements, Pergamon Press."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Kutch, J.J., and Valero-Cuevas, F.J. (2012). Challenges and new approaches to proving the existence of muscle synergies of neural origin. PLoS Comput. Biol., 8.","DOI":"10.1371\/journal.pcbi.1002434"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1007\/s00221-008-1355-3","article-title":"The statistics of natural hand movements","volume":"188","author":"Ingram","year":"2008","journal-title":"Exp. Brain Res."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Bizzi, E., and Cheung, V.C. (2013). The neural origin of muscle synergies. Front. Comput. Neurosci., 7.","DOI":"10.3389\/fncom.2013.00051"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"d\u2019Avella, A., and Lacquaniti, F. (2013). Control of reaching movements by muscle synergy combinations. Front. Comput. Neurosci., 7.","DOI":"10.3389\/fncom.2013.00042"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2199","DOI":"10.1152\/jn.00222.2005","article-title":"Matrix factorization algorithms for the identification of muscle synergies: Evaluation on simulated and experimental data sets","volume":"95","author":"Tresch","year":"2006","journal-title":"J. Neurophysiol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1016\/j.brainresrev.2007.08.004","article-title":"Combining modules for movement","volume":"57","author":"Bizzi","year":"2008","journal-title":"Brain Res. Rev."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1007\/s00422-013-0548-4","article-title":"Evidence of muscle synergies during human grasping","volume":"107","author":"Castellini","year":"2013","journal-title":"Biol. Cybern."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Tagliabue, M., Ciancio, A.L., Brochier, T., Eskiizmirliler, S., and Maier, M.A. (2015). Differences between kinematic synergies and muscle synergies during two-digit grasping. Front. Hum. Neurosci., 9.","DOI":"10.3389\/fnhum.2015.00165"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"6116","DOI":"10.1038\/s41598-020-63092-7","article-title":"Sharing of hand kinematic synergies across subjects in daily living activities","volume":"10","author":"Vergara","year":"2020","journal-title":"Sci. Rep."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1016\/j.apergo.2016.03.003","article-title":"Using kinematic reduction for studying grasping postures. An application to power and precision grasp of cylinders","volume":"56","author":"Vergara","year":"2016","journal-title":"Appl. Ergon."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1556","DOI":"10.1109\/TNSRE.2020.2998642","article-title":"Hand kinematics characterization while performing activities of daily living through kinematics reduction","volume":"28","author":"Vergara","year":"2020","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e16202","DOI":"10.1016\/j.heliyon.2023.e16202","article-title":"Muscle synergies for evaluating upper limb in clinical applications: A systematic review","volume":"9","author":"Zhao","year":"2023","journal-title":"Heliyon"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"814","DOI":"10.1038\/s41597-023-02723-w","article-title":"Electromyography and kinematics data of the hand in activities of daily living with special interest for ergonomics","volume":"10","author":"Vergara","year":"2023","journal-title":"Sci. Data"},{"key":"ref_15","unstructured":"Hermens, H.J., Freriks, B., Disselhorst-Klug, C., and Rau, G. (1999). European Recommendations for Surface Electromyography (SENIAM), Roessingh Research and Development."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1383","DOI":"10.1109\/TBME.2004.827556","article-title":"Assessment of average muscle fiber conduction velocity from surface EMG signals during fatiguing dynamic contractions","volume":"51","author":"Farina","year":"2004","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"14652","DOI":"10.1073\/pnas.1212056109","article-title":"Muscle synergy patterns as physiological markers of motor cortical damage","volume":"109","author":"Cheung","year":"2012","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Santello, M., Baud-Bovy, G., and J\u00f6rntell, H. (2013). Neural bases of hand synergies. Front. Comput. Neurosci., 7.","DOI":"10.3389\/fncom.2013.00023"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Overduin, S.A., d\u2019Avella, A., Carmena, J.M., and Bizzi, E. (2014). Muscle synergies evoked by microstimulation are preferentially encoded during behavior. Front. Comput. Neurosci., 8.","DOI":"10.3389\/fncom.2014.00020"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1530","DOI":"10.1152\/jn.00810.2005","article-title":"Muscle synergy organization is robust across a variety of postural perturbations","volume":"96","author":"Macpherson","year":"2006","journal-title":"J. Neurophysiol."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Alnajjar, F., Wojtara, T., Kimura, H., and Shimoda, S. (2013). Muscle synergy space: Learning model to create an optimal muscle synergy. Front. Comput. Neurosci., 7.","DOI":"10.3389\/fncom.2013.00136"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"675","DOI":"10.1152\/jn.00245.2013","article-title":"A unifying model of concurrent spatial and temporal modularity in muscle activity","volume":"111","author":"Delis","year":"2014","journal-title":"J. Neurophysiol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"17041","DOI":"10.1523\/JNEUROSCI.4297-10.2010","article-title":"Spinal interneurons facilitate coactivation of hand muscles during a precision grip task in monkeys","volume":"30","author":"Takei","year":"2010","journal-title":"J. Neurosci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1186\/s12984-023-01236-2","article-title":"Developing new intermuscular coordination patterns through an electromyographic signal-guided training in the upper extremity","volume":"20","author":"Seo","year":"2023","journal-title":"J. Neuroeng. Rehabil."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Latash, M.L. (2021). Understanding synergy: A single concept at different levels of analysis?. Front. Syst. Neurosci., 15.","DOI":"10.3389\/fnsys.2021.735406"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1381","DOI":"10.1152\/jn.1991.65.6.1381","article-title":"Individuated finger movements of rhesus monkeys: A means of quantifying the independence of the digits","volume":"65","author":"Schieber","year":"1991","journal-title":"J. Neurophysiol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"373957","DOI":"10.1155\/2014\/373957","article-title":"Candidates for synergies: Linear discriminants versus principal components","volume":"2014","author":"Vinjamuri","year":"2014","journal-title":"Comput. Intell. Neurosci."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"541","DOI":"10.1016\/j.tics.2012.09.008","article-title":"The computational and neural basis of voluntary motor control and planning","volume":"16","author":"Scott","year":"2012","journal-title":"Trends Cogn. Sci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"425","DOI":"10.1016\/j.neuron.2011.10.006","article-title":"Computational mechanisms of sensorimotor control","volume":"72","author":"Franklin","year":"2011","journal-title":"Neuron"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Rigoux, L., and Guigon, E. (2012). A model of reward- and effort-based optimal decision making and motor control. PLoS Comput. Biol., 8.","DOI":"10.1371\/journal.pcbi.1002716"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Zandigohar, M., Han, M., Sharif, M., G\u00fcnay, S.Y., Furmanek, M.P., Yarossi, M., Bonato, P., Onal, C., Pad\u0131r, T., and Erdo\u011fmu\u015f, D. (2024). Multimodal fusion of EMG and vision for human grasp intent inference in prosthetic hand control. Front. Robot. AI, 11.","DOI":"10.3389\/frobt.2024.1312554"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"026043","DOI":"10.1088\/1741-2552\/ad38dd","article-title":"Arm muscle synergies enhance hand posture prediction in combination with forearm muscle synergies","volume":"21","author":"Tanzarella","year":"2024","journal-title":"J. Neural Eng."},{"key":"ref_33","unstructured":"Scotto di Luzio, F., Cordella, F., Bravi, M., Santacaterina, F., Bressi, F., Sterzi, S., and Zollo, L. (2022). Modification of hand muscular synergies in stroke patients after robot-aided rehabilitation. Appl. Sci., 12."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"767","DOI":"10.23736\/S1973-9087.24.08438-7","article-title":"Muscle synergies in upper limb stroke rehabilitation: A scoping review","volume":"60","author":"Facciorusso","year":"2024","journal-title":"Eur. J. Phys. Rehabil. Med."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1152\/jn.00067.2024","article-title":"Evidence of the existence of multiple modules for the stroke-caused flexion synergy from Fugl-Meyer assessment scores","volume":"132","author":"Kim","year":"2024","journal-title":"J. Neurophysiol."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/13\/5268\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,6]],"date-time":"2026-07-06T14:42:22Z","timestamp":1783348942000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/13\/5268"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,6]]},"references-count":35,"journal-issue":{"issue":"13","published-online":{"date-parts":[[2026,7]]}},"alternative-id":["jcm15135268"],"URL":"https:\/\/doi.org\/10.3390\/jcm15135268","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,6]]}}}