{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T01:46:35Z","timestamp":1776822395341,"version":"3.51.2"},"reference-count":40,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2020,12,16]],"date-time":"2020-12-16T00:00:00Z","timestamp":1608076800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100017090","name":"Sony Corporation","doi-asserted-by":"publisher","award":["none"],"award-info":[{"award-number":["none"]}],"id":[{"id":"10.13039\/100017090","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Prolonged computer work and smartphone use can cause stiffness of the neck and shoulder muscles, including the trapezius muscle. Hence, muscle hardness quantification is clinically beneficial. The present study aimed to examine the reliability of trapezius muscle hardness measurement using a portable muscle hardness meter and ultrasound strain elastography. Overall, 20 healthy young men participated in this study. Prior to measurement, the participant\u2019s subjective symptoms, particularly shoulder muscle stiffness, were rated using an 11-point verbal scale. Furthermore, hardness of the right and left upper trapezius muscles was assessed. In the strain elastography assessment, muscle hardness was evaluated using strain ratio. Results showed that, in quantifying upper trapezius muscle hardness, both portable muscle hardness meter and strain elastography had an excellent intra-tester reliability (&gt;0.9). However, the correlation coefficients between muscle hardness values assessed using a muscle hardness meter and those evaluated with strain elastography did not significantly differ, and the scores for subjective shoulder stiffness did not correspond to muscle hardness values. Therefore, the hardness of the trapezius muscle does not directly reflect the subjective shoulder stiffness. Future studies should thoroughly examine the location of the shoulder stiffness, and check whether it is accompanied by local pain or tenderness.<\/jats:p>","DOI":"10.3390\/s20247200","type":"journal-article","created":{"date-parts":[[2020,12,16]],"date-time":"2020-12-16T09:21:15Z","timestamp":1608110475000},"page":"7200","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":39,"title":["Reliability of Trapezius Muscle Hardness Measurement: A Comparison between Portable Muscle Hardness Meter and Ultrasound Strain Elastography"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9750-8828","authenticated-orcid":false,"given":"Tomonori","family":"Sawada","sequence":"first","affiliation":[{"name":"Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4211-1759","authenticated-orcid":false,"given":"Hiroki","family":"Okawara","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1105-2669","authenticated-orcid":false,"given":"Daisuke","family":"Nakashima","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan"},{"name":"Diagnosis and Treatment Division, Nagura Orthopedic Clinic, Nihombashi Nomura Building (YUITO 7F) 2-4-3 Nihombashi Muromachi, Chuo-ku, Tokyo 103-0022, Japan"}]},{"given":"Shuhei","family":"Iwabuchi","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan"}]},{"given":"Morio","family":"Matsumoto","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan"}]},{"given":"Masaya","family":"Nakamura","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan"}]},{"given":"Takeo","family":"Nagura","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan"},{"name":"Diagnosis and Treatment Division, Nagura Orthopedic Clinic, Nihombashi Nomura Building (YUITO 7F) 2-4-3 Nihombashi Muromachi, Chuo-ku, Tokyo 103-0022, Japan"},{"name":"Department of Clinical Biomechanics, Keio University School of Medicine, Shinjuku, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan"}]}],"member":"1968","published-online":{"date-parts":[[2020,12,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1016\/j.pathophys.2004.03.001","article-title":"Neck and shoulder pain related to computer use","volume":"11","author":"Ming","year":"2004","journal-title":"Pathophysiology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1007\/s00421-004-1220-4","article-title":"Clinical signs and physical function in neck and upper extremities among elderly female computer users: The NEW study","volume":"96","author":"Kadefors","year":"2006","journal-title":"Eur. 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