{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,20]],"date-time":"2026-08-20T17:24:31Z","timestamp":1787246671312,"version":"build-2736575974"},"reference-count":39,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,20]],"date-time":"2026-08-20T00:00:00Z","timestamp":1787184000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J. Clin. Med.","JCM"],"abstract":"<jats:p>Objective: To examine acute BEFORE\u2013AFTER changes in maximum, mean, and median surface-EMG RMS amplitudes recorded from four shoulder-girdle muscles around scheduled collegiate volleyball training sessions. Methods: Sixteen male collegiate volleyball players representing one university team participated in this exploratory prospective repeated-measures study. Surface EMG was recorded from the upper trapezius, lower trapezius, infraspinatus, and serratus anterior during muscle-specific maximal voluntary isometric effort tasks. A standardized dynamic warm-up was completed before the BEFORE assessment. Surface EMG was then recorded immediately after warm-up and before the volleyball-specific training components of the session (BEFORE), and again within 5\u201310 min after completion of the scheduled team-training session (AFTER), on three weekly measurement days. For each EMG outcome, the main inferential estimand was the marginal AFTER\u2013BEFORE contrast averaged across muscles and measurement days. Linear mixed-effects models included assessment condition, muscle, measurement day, and the assessment condition \u00d7 muscle term; interaction analyses were treated as exploratory because the participant-level sample comprised 16 independent experimental units. Marginal AFTER\u2013BEFORE contrasts were adjusted across the three RMS-amplitude outcomes using the Bonferroni method. Results: Mean RMS amplitude was lower AFTER than BEFORE the training sessions by 4.16 \u00b5V (95% CI: \u22126.32 to \u22122.01; Bonferroni-adjusted p &lt; 0.001). Maximum RMS amplitude was also lower by 5.77 \u00b5V (95% CI: \u221211.19 to \u22120.35), but this contrast was not supported after multiplicity adjustment (adjusted p = 0.115). Median RMS amplitude showed an estimated increase of 3.88 \u00b5V (95% CI: \u22120.19 to 7.94; adjusted p = 0.181). Exploratory assessment condition \u00d7 muscle interactions were not statistically significant for any of the three RMS-amplitude outcomes. Conclusions: Only the decrease in mean RMS amplitude remained statistically supported after adjustment across the three EMG outcomes. Because both assessments were performed after the standardized warm-up, warm-up status was held constant with respect to completion of the warm-up. The AFTER assessment additionally followed the subsequent volleyball-specific training components and a 5\u201310-min post-session interval. Accordingly, the contrast represents a within-session AFTER\u2013BEFORE difference associated with the intervening training exposure and temporal\/order effects rather than an isolated causal effect of training. Exploratory condition \u00d7 muscle interactions were not statistically significant, but the small sample does not establish equivalent responses among muscles. The findings do not establish altered mechanical force or localized neuromuscular fatigue.<\/jats:p>","DOI":"10.3390\/jcm15166460","type":"journal-article","created":{"date-parts":[[2026,8,20]],"date-time":"2026-08-20T16:05:19Z","timestamp":1787241919000},"page":"6460","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Surface-EMG Amplitude Differences Before and After Scheduled University Team Training Following a Standardized Warm-Up in Male Collegiate Volleyball Players"],"prefix":"10.3390","volume":"15","author":[{"given":"Maria","family":"Migda\u0142","sequence":"first","affiliation":[{"name":"Student Scientific Circle of Orthopedic Manual Therapy, Medical University of Gda\u0144sk, 80-211 Gda\u0144sk, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Magdalena","family":"Wiacek","sequence":"additional","affiliation":[{"name":"Faculty of Medical Sciences and Health Sciences, University of Radom, Chrobrego 27, 26-600 Radom, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7074-0472","authenticated-orcid":false,"given":"Rafa\u0142","family":"Studnicki","sequence":"additional","affiliation":[{"name":"Student Scientific Circle of Orthopedic Manual Therapy, Medical University of Gda\u0144sk, 80-211 Gda\u0144sk, Poland"},{"name":"Department of Physiotherapy, Medical University of Gda\u0144sk, Ul. D\u0119binki 7, 80-211 Gda\u0144sk, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"368","DOI":"10.1177\/1941738110374624","article-title":"Upper Limb Biomechanics During the Volleyball Serve and Spike","volume":"2","author":"Reeser","year":"2010","journal-title":"Sports Health"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"732","DOI":"10.1080\/17461391.2013.773090","article-title":"Overuse in Volleyball Training\/Practice: A Review on Shoulder and Spine-Related Injuries","volume":"13","author":"Seminati","year":"2013","journal-title":"Eur. J. Sport Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1590\/bjpt-rbf.2014.0109","article-title":"Prevention of Shoulder Injuries in Overhead Athletes: A Science-Based Approach","volume":"19","author":"Cools","year":"2015","journal-title":"Braz. J. Phys. 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