{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T05:39:29Z","timestamp":1789105169226,"version":"build-2803163510"},"reference-count":39,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T00:00:00Z","timestamp":1771545600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T00:00:00Z","timestamp":1771545600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/501100000024","name":"Canadian Institutes of Health Research","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000024","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["physoc.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Experimental Physiology"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    Head\u2010down tilt bedrest (HDBR) models the effects of mechanical unloading on neuromuscular function. The efficacy of exercise in preserving motor unit (MU) function in older adults during HDBR remains unclear. This study investigated the effects of 14\u2010day HDBR on MU properties in older adults and the protective role of exercise. Fifteen participants aged 55\u201365\u00a0years were randomized to Control group (\n                    <jats:italic>n<\/jats:italic>\n                    \u00a0=\u00a07, passive mobilization only) or Exercise group (\n                    <jats:italic>n<\/jats:italic>\n                    \u00a0=\u00a08, daily mixed resistance and aerobic training) during 14\u00a0days of strict HDBR. Knee extensor strength and leg lean mass were measured, and intramuscular EMG was used to record MU firing rate (MUFR), MU potential (MUP) area and complexity, and neuromuscular junction (NMJ) transmission instability during contractions normalized to 25% of pre\u2010bedrest strength. Plasma C\u2010terminal agrin fragment (CAF) was also measured. Following HDBR, knee extensor strength decreased more in the Control group (\u221233.4\u00a0N\u00a0m;\n                    <jats:italic>P\u00a0<\/jats:italic>\n                    &lt;\u00a00.001; \u223c18% decrease) than in the Exercise group (\u221214.5\u00a0N\u00a0m;\n                    <jats:italic>P\u00a0<\/jats:italic>\n                    =\u00a00.027; \u223c8% decrease; interaction\n                    <jats:italic>P\u00a0<\/jats:italic>\n                    =\u00a00.045). Leg lean mass decreased similarly in both groups (\u22120.418\u00a0kg;\n                    <jats:italic>P\u00a0<\/jats:italic>\n                    =\u00a00.013). Exercise prevented the decrease in MUP area observed in Controls (\u221265\u00a0mV\u00b7ms,\n                    <jats:italic>P\u00a0<\/jats:italic>\n                    =\u00a00.240\u00a0vs. \u2212253\u00a0mV\u00b7ms,\n                    <jats:italic>P<\/jats:italic>\n                    \u00a0&lt;\u00a00.001) and led to a reduction in MUFR (\u22121.05\u00a0pulses\/s,\n                    <jats:italic>P\u00a0<\/jats:italic>\n                    &lt;\u00a00.001) not seen in Controls. NMJ transmission stability and CAF levels were unchanged in both groups. HDBR reduced leg lean mass and strength. Exercise attenuated declines in strength and MUP area, likely by preserving muscle fibre size despite reduced MUFR, without evidence of NMJ disruption. Exercise effectively attenuates neuromuscular decrements following HDBR in older adults, with implications for clinical care and spaceflight.\n                  <\/jats:p>","DOI":"10.1113\/ep093398","type":"journal-article","created":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T17:41:36Z","timestamp":1771609296000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Exercise during 14 days of head down tilt bedrest attenuates motor unit impairments in older humans"],"prefix":"10.1113","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9824-2072","authenticated-orcid":false,"given":"Philippe","family":"St\u2010Martin","sequence":"first","affiliation":[{"name":"Faculty of Physical Activity Sciences Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"},{"name":"Research Centre on Aging Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"},{"name":"Institut Pluridisciplinaire Hubert Curien Universit\u00e9 de Strasbourg, Centre National de la Recherche Scientifique  Strasbourg France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9101-9900","authenticated-orcid":false,"given":"Jean\u2010Christophe","family":"Lagac\u00e9","sequence":"additional","affiliation":[{"name":"Faculty of Physical Activity Sciences Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"},{"name":"Research Centre on Aging Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-7105-3045","authenticated-orcid":false,"given":"Mathil","family":"Ruel","sequence":"additional","affiliation":[{"name":"Faculty of Physical Activity Sciences Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"},{"name":"Research Centre on Aging Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ahmed","family":"Ghachem","sequence":"additional","affiliation":[{"name":"Faculty of Physical Activity Sciences Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guillaume","family":"L\u00e9onard","sequence":"additional","affiliation":[{"name":"Research Centre on Aging Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"},{"name":"Faculty of Medicine and Health Sciences Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7804-4631","authenticated-orcid":false,"given":"Eleonor","family":"Riesco","sequence":"additional","affiliation":[{"name":"Faculty of Physical Activity Sciences Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"},{"name":"Research Centre on Aging Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mathew","family":"Piasecki","sequence":"additional","affiliation":[{"name":"Centre of Metabolism, Ageing &amp; Physiology (COMAP) Injury, Recovery &amp; Inflammation Sciences, School of Medicine, NIHR Nottingham BRC University of Nottingham, Royal Derby Hospital Centre  Derby UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3659-0773","authenticated-orcid":false,"given":"Jamie S.","family":"McPhee","sequence":"additional","affiliation":[{"name":"Department of Sport and Exercise Sciences Manchester Metropolitan University Institute of Sport  Manchester UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Isabelle J.","family":"Dionne","sequence":"additional","affiliation":[{"name":"Faculty of Physical Activity Sciences Universit\u00e9 de Sherbrooke  Sherbrooke Quebec Canada"},{"name":"Research Centre on Aging Universit\u00e9 de Sherbrooke  Sherbrooke 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