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Here, we investigated the viability of extracting movement augmentation control signals from the muscles of the wrist complex. Our study assessed (i) if controlled variation of the muscle activation patterns in the wrist joint\u2019s null-space is possible; and (ii) whether force and null-space cursor targets could be reached concurrently. During the null-space target reaching condition, participants used muscle-to-force null-space muscle activation to move their cursor towards a displayed target while minimising the exerted force as visualised through the cursor\u2019s size. Initial targets were positioned to require natural co-contraction in the null-space and if participants showed a consistent ability to reach for their current target, they would rotate 5\n                    <jats:inline-formula>\n                      <jats:alternatives>\n                        <jats:tex-math>$$^\\circ$$<\/jats:tex-math>\n                        <mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                          <mml:mmultiscripts>\n                            <mml:mrow\/>\n                            <mml:mrow\/>\n                            <mml:mo>\u2218<\/mml:mo>\n                          <\/mml:mmultiscripts>\n                        <\/mml:math>\n                      <\/jats:alternatives>\n                    <\/jats:inline-formula>\n                    incrementally to generate muscle activation patterns further away from their natural co-contraction. In contrast, during the concurrent target reaching condition participants were required to match a target position and size, where their cursor position was instead controlled by their exerted flexion\u2013extension and radial-ulnar deviation, while its size was changed by their natural co-contraction magnitude. The results collected from 10 participants suggest that while there was variation in each participant\u2019s co-contraction behaviour, most did not possess the ability to control this variation for muscle-to-force null-space virtual reaching. In contrast, participants did show a direction and target size dependent ability to vary isometric force and co-contraction activity concurrently. Our results indicate the limitations of using the muscle-to-force null-space activity of joints with a low level of redundancy as a possible command signal for movement augmentation.\n                  <\/jats:p>","DOI":"10.1038\/s41598-024-69353-z","type":"journal-article","created":{"date-parts":[[2024,9,4]],"date-time":"2024-09-04T12:02:22Z","timestamp":1725451342000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Control limitations in the null-space of the wrist muscle system"],"prefix":"10.1038","volume":"14","author":[{"given":"Meng-Jung","family":"Lee","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0733-265X","authenticated-orcid":false,"given":"Jonathan","family":"Eden","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sergio","family":"Gurgone","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Denise J","family":"Berger","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniele","family":"Borzelli","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrea","family":"d\u2019Avella","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8125-5205","authenticated-orcid":false,"given":"Carsten","family":"Mehring","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2123-0185","authenticated-orcid":false,"given":"Etienne","family":"Burdet","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2024,9,4]]},"reference":[{"key":"69353_CR1","doi-asserted-by":"publisher","first-page":"1293","DOI":"10.1016\/S0039-6109(03)00164-6","volume":"83","author":"GH Ballantyne","year":"2003","unstructured":"Ballantyne, G. H. & Moll, F. The da Vinci telerobotic surgical system: the virtual operative field and telepresence surgery. Surg. Clin. North Am. 83, 1293\u20131304 (2003).","journal-title":"Surg. Clin. North Am."},{"key":"69353_CR2","doi-asserted-by":"publisher","first-page":"623","DOI":"10.1109\/TMRB.2021.3086016","volume":"3","author":"B Yang","year":"2021","unstructured":"Yang, B., Huang, J., Chen, X., Xiong, C. & Hasegawa, Y. Supernumerary robotic limbs: a review and future outlook. IEEE Trans. Med. Robot. Bionics 3, 623\u2013639 (2021).","journal-title":"IEEE Trans. Med. Robot. Bionics"},{"key":"69353_CR3","doi-asserted-by":"publisher","first-page":"1345","DOI":"10.1038\/s41467-022-28725-7","volume":"13","author":"J Eden","year":"2022","unstructured":"Eden, J. et al. Principles of human movement augmentation and the challenges in making it a reality. Nat. Commun. 13, 1345 (2022).","journal-title":"Nat. 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