{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,7]],"date-time":"2026-02-07T08:16:15Z","timestamp":1770452175255,"version":"3.49.0"},"reference-count":65,"publisher":"American Physiological Society","issue":"4","funder":[{"DOI":"10.13039\/100009123","name":"Norwegian University of Science and Technology","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100009123","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Heart and Circulatory Physiology"],"published-print":{"date-parts":[[2018,4,1]]},"abstract":"<jats:p> Maximal strength training (MST) improves work efficiency. However, since blood flow is greatly dictated by muscle contractions in arms during exercise and vascular conductance is lower, it has been indicated that arms rely more upon adapting oxygen extraction than legs in response to the enhanced work efficiency. Thus, to investigate if metabolic and vascular responses are arm specific, we used Doppler-ultrasound and a catheter placed in the subclavian vein to measure blood flow and the arteriovenous oxygen difference during steady-state work in seven young men [24\u2009\u00b1\u20093 (SD) yr] following 6 wk of handgrip MST. As expected, MST improved maximal strength (49\u2009\u00b1\u20099 to 62\u2009\u00b1\u200910 kg) and the rate of force development (923\u2009\u00b1\u2009224 to 1,086\u2009\u00b1\u2009238 N\/s), resulting in a reduced submaximal oxygen uptake (30\u2009\u00b1\u20099 to 24\u2009\u00b1\u200910 ml\/min) and concomitantly increased work efficiency (9.3\u2009\u00b1\u20092.5 to 12.4\u2009\u00b1\u20093.9%) (all P &lt; 0.05). In turn, the work efficiency improvement was associated with reduced blood flow (486\u2009\u00b1\u2009102 to 395\u2009\u00b1\u2009114 ml\/min), mediated by a lower blood velocity (43\u2009\u00b1\u20098 to 32\u2009\u00b1\u20096 cm\/s) (all P &lt; 0.05). Conduit artery diameter and the arteriovenous oxygen difference remained unaltered. The maximal work test revealed an increased time to exhaustion (949\u2009\u00b1\u2009239 to 1,102\u2009\u00b1 292 s) and maximal work rate (both P &lt; 0.05) but no change in peak oxygen uptake. In conclusion, despite prior indications of metabolic and vascular limb-specific differences, these results reveal that improved work efficiency after small muscle mass strength training in the upper extremities is accompanied by a blood flow reduction and coheres with what has been documented for lower extremities. <\/jats:p><jats:p> NEW &amp; NOTEWORTHY Maximal strength training increases skeletal muscle work efficiency. Oxygen extraction has been indicated to be the adapting component with this increased work efficiency in arms. However, we document that decreased blood flow, achieved by blood velocity reduction, is the adapting mechanism responding to the improved aerobic metabolism in the forearm musculature. <\/jats:p>","DOI":"10.1152\/ajpheart.00435.2017","type":"journal-article","created":{"date-parts":[[2017,12,29]],"date-time":"2017-12-29T12:41:54Z","timestamp":1514551314000},"page":"H853-H862","source":"Crossref","is-referenced-by-count":20,"title":["Maximal strength training-induced improvements in forearm work efficiency are associated with reduced blood flow"],"prefix":"10.1152","volume":"314","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1538-6156","authenticated-orcid":false,"given":"Ole Kristian","family":"Berg","sequence":"first","affiliation":[{"name":"Faculty of Health and Social Sciences, Molde University College, Molde, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stian Kwak","family":"Nyberg","sequence":"additional","affiliation":[{"name":"Department of 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