{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T04:53:27Z","timestamp":1791176007069,"version":"4.1.0"},"reference-count":18,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T00:00:00Z","timestamp":1791158400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>The repeated bout effect (RBE) protects skeletal muscles from exercise-induced muscle damage (EIMD). While homologous contralateral RBE is well-documented, the existence of heterologous RBE\u2014specifically whether lower limb conditioning can protect upper limb muscles\u2014remains debated.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>This study investigated whether high-intensity eccentric exercise of the knee extensors attenuates eccentric exercise-induced neuromuscular fatigue and muscle stiffness and preserves neuromuscular control in the contralateral elbow flexors.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Twenty-four sedentary young women were randomized into a Knee Extensor-Contralateral Elbow Flexor (KE-CEF) group and a Control Elbow Flexor (CEF) group. The KE-CEF group performed 60 maximal eccentric contractions (MaxEc) of the non-dominant knee extensors, followed 14 days later by 30 MaxEc of the dominant elbow flexors. The CEF group performed only the elbow flexor MaxEc. Outcome measures, including maximal voluntary isometric contraction (MVC), Acoustic Radiation Force Impulse (ARFI) imaging, and the Joint Release Angle (JRA) test, were assessed up to 120\u00a0h post-exercise.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      The KE-CEF group demonstrated significantly less MVC loss immediately post-exercise compared to the CEF group (70.00 \u00b1 19.85% vs. 57.67 \u00b1 8.28%;\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u00a00.029). Furthermore, prior lower limb conditioning significantly attenuated peak muscle stiffness at 48\u00a0h (ARFI: 108.25 \u00b1 4.73% vs. 125.63 \u00b1 6.99% in CEF) and entirely preserved JRA proprioceptive stability during peak fatigue (26.58 \u00b1 0.78\u00b0 vs. 24.75 \u00b1 1.55\u00b0; between-group\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u00a00.001).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>These findings provide novel evidence that a single bout of lower limb eccentric exercise confers a robust heterologous protective effect on upper limb muscles, highlighting the role of global systemic and neural adaptations in cross-limb rehabilitation strategies.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fphys.2026.1823848","type":"journal-article","created":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T04:37:24Z","timestamp":1791175044000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Heterologous contralateral repeated bout effect: eccentric knee extensor conditioning enhances neuromuscular fatigue resistance and attenuates muscle stiffness in contralateral elbow flexors in young women"],"prefix":"10.3389","volume":"17","author":[{"given":"Chung-Chan","family":"Hsieh","sequence":"first","affiliation":[{"name":"Department of Exercise and Health Sciences, College of Kinesiology, University of Taipei","place":["Taipei City, Taiwan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Szu-Kai","family":"Fu","sequence":"additional","affiliation":[{"name":"Department of Exercise and Health Sciences, College of Kinesiology, University of Taipei","place":["Taipei City, Taiwan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu-Lin","family":"Ning","sequence":"additional","affiliation":[{"name":"Department of Martial Arts, College of Kinesiology, University of Taipei","place":["Taipei City, Taiwan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chin-Fang","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Martial Arts, College of Kinesiology, University of Taipei","place":["Taipei City, Taiwan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Che-Ming","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Facility Planning, Ministry of Sports","place":["Taipei City, Taiwan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chia-Hsien","family":"Yu","sequence":"additional","affiliation":[{"name":"Department of Exercise and Health Sciences, College of Kinesiology, University of Taipei","place":["Taipei City, Taiwan"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,10,5]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"36","DOI":"10.1123\/pes.2019-0079","article-title":"Unilateral elbow flexion and leg press training induce cross-education but not global training gains in children","volume":"32","author":"Ben Othman","year":"2020","journal-title":"Pediatr. Exerc Sci."},{"key":"B2","doi-asserted-by":"publisher","first-page":"220","DOI":"10.1123\/pes.2024-0027","article-title":"Age, sex, and training specific effects on cross-education training","volume":"37","author":"Ben Othman","year":"2025","journal-title":"Pediatr. Exerc Sci."},{"key":"B3","doi-asserted-by":"publisher","first-page":"62","DOI":"10.3390\/sports11030062","article-title":"The contralateral repeated bout effect of elbow flexors is not observed in young women following mild muscle damage from eccentric exercises","volume":"11","author":"Brown","year":"2023","journal-title":"Sports (Basel)"},{"key":"B4","doi-asserted-by":"publisher","first-page":"247","DOI":"10.1016\/j.freeradbiomed.2024.09.047","article-title":"The repeated bout effect evokes the training-induced skeletal muscle cellular memory","volume":"225","author":"Calvo-Rubio","year":"2024","journal-title":"Free Radic. Biol. 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