{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T19:43:11Z","timestamp":1787773391647,"version":"build-2784847793"},"reference-count":28,"publisher":"SAGE Publications","issue":"7","license":[{"start":{"date-parts":[[2020,7,1]],"date-time":"2020-07-01T00:00:00Z","timestamp":1593561600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Orthopaedic Journal of Sports Medicine"],"published-print":{"date-parts":[[2020,7,1]]},"abstract":"<jats:sec>\n                    <jats:title>Background:<\/jats:title>\n                    <jats:p>Isotonic exercise is commonly adopted for shoulder rehabilitation, but the efficacy of isokinetic exercise for rehabilitation has not been evaluated.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Purpose:<\/jats:title>\n                    <jats:p>To evaluate the efficacy of isotonic and isokinetic external shoulder rotation exercises.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Study Design:<\/jats:title>\n                    <jats:p>Controlled laboratory study.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>Using surface electromyography (EMG) and the Biodex system, we investigated the EMG amplitude of the infraspinatus (IS), total work (tWK), and EMG(IS)\/tWK ratio and examined the relative IS and posterior deltoid (PD) contributions to all exercises. A total of 24 healthy participants without musculoskeletal injuries were included. Participants performed isotonic external shoulder rotation at 10%, 20%, 30%, 40%, and 50% of the maximum voluntary isometric contraction (MVIC) as well as isokinetic external shoulder rotation at angular velocities of 60, 120, 180, 240, and 300 deg\/s. Levels of intensity were classified from 1 to 5: level 1 corresponded to 10% of the MVIC and a 300-deg\/s angular velocity; level 2 corresponded to 20% MVIC and 240 deg\/s; level 3 corresponded to 30% MVIC and 180 deg\/s; level 4 corresponded to 40% MVIC and 120 deg\/s; and level 5 corresponded to 50% MVIC and 60 deg\/s. Normalized IS and tWK amplitudes were calculated for each exercise.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>During isotonic exercise, the EMG(IS)\/tWK ratio significantly decreased from level 5 to 3, 2, and 1; from level 4 to 2 and 1; and from level 3 to 1. During isokinetic exercise, the EMG(IS)\/tWK ratio at level 3 was greater than that at all other levels except level 1. Statistical differences were found between isotonic and isokinetic modes at levels 1, 2, and 3. The IS\/PD activation ratios were not significantly different between exercise modes at any level.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>Isokinetic resistance may provide more effective stimulation of the IS muscle compared with isotonic resistance.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Clinical Relevance:<\/jats:title>\n                    <jats:p>Isokinetic exercise needs to be considered as a method of rehabilitation that effectively increases infraspinatus muscle activity.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/2325967120932459","type":"journal-article","created":{"date-parts":[[2020,7,7]],"date-time":"2020-07-07T14:16:21Z","timestamp":1594131381000},"update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":11,"title":["Evaluation of the Electromyographic Amplitude-to-Work Ratio in the Infraspinatus Muscle During External Shoulder Rotation Exercises: A Comparison of Concentric Isotonic and Isokinetic Exercises"],"prefix":"10.1177","volume":"8","author":[{"given":"Jung-Ho","family":"Park","sequence":"first","affiliation":[{"name":"Korea University College of Medicine, Seoul, Republic of Korea."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seok Won","family":"Chung","sequence":"additional","affiliation":[{"name":"Konkuk University School of Medicine, Seoul, Republic of Korea."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seoung-Joon","family":"Lee","sequence":"additional","affiliation":[{"name":"Konkuk University School of Medicine, Seoul, Republic of Korea."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jong-Won","family":"Lee","sequence":"additional","affiliation":[{"name":"Konkuk University School of Medicine, Seoul, Republic of Korea."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kyung-Soo","family":"Oh","sequence":"additional","affiliation":[{"name":"Konkuk University School of Medicine, Seoul, Republic of Korea."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2020,7,7]]},"reference":[{"key":"bibr1-2325967120932459","doi-asserted-by":"publisher","DOI":"10.1016\/j.jse.2006.11.007"},{"key":"bibr2-2325967120932459","doi-asserted-by":"publisher","DOI":"10.2519\/jospt.2007.2448"},{"key":"bibr3-2325967120932459","volume-title":"Isokinetics 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