{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T08:08:33Z","timestamp":1784102913368,"version":"3.55.0"},"reference-count":34,"publisher":"PeerJ","license":[{"start":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T00:00:00Z","timestamp":1784073600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Velocity-based training has emerged as a leading approach for quantifying training loads. Therefore, valid and reliable devices must be used to evaluate both movement velocity and power.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>\n                      This study determined the validity and reliability of the Valkyria Trainer Free\n                      <jats:sup>\u00ae<\/jats:sup>\n                      linear position transducer (VTF\n                      <jats:sup>\u00ae<\/jats:sup>\n                      LPT) during the propulsive phase of the bench press in physically healthy individuals.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and Methods<\/jats:title>\n                    <jats:p>\n                      Nineteen physically healthy men participated in the study (22.7 \u00b1 2.1 years). A repeated-measures design was used to compare the inter-day test\u2013retest reliability of velocity and power, while validity was determined by comparing the VTF\n                      <jats:sup>\u00ae<\/jats:sup>\n                      LPT with the Chrono-Jump\n                      <jats:sup>\u00ae<\/jats:sup>\n                      LPT. The analysis consisted of the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and coefficient of variation (CV) for slow velocity zone: 0.08\u20130.49 m\u00b7s\n                      <jats:sup>\u22121<\/jats:sup>\n                      , power zone: 0.50\u20130.99 m\u00b7s\n                      <jats:sup>\u22121<\/jats:sup>\n                      , and fast velocity zone: 1.00\u20131.56 m\u00b7s\n                      <jats:sup>\u22121<\/jats:sup>\n                      . A CV \u2264 10% and an ICC \u2265 0.80 were considered acceptable reliability, whereas a CV \u2264 5% and an ICC \u2265 0.90 were considered high reliability.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>For vertical velocity, the \u201cpower zone\u201d and \u201cfast velocity zone\u201d showed a high threshold for CV (\u22645%), while the \u201cslow velocity zone\u201d showed an acceptable threshold with a CV of 7.94. For power, the \u201cslow velocity zone\u201d showed an acceptable threshold for CV (\u226410%), while the \u201cfast velocity zone\u201d and \u201cpower zone\u201d showed a CV equivalent to 10.8 and 4.8%, respectively.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>\n                      The study\u2019s results demonstrated that VTF\n                      <jats:sup>\u00ae<\/jats:sup>\n                      LPT is valid and reliable for assessing velocity and power in physically healthy individuals.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.7717\/peerj.21357","type":"journal-article","created":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T08:00:20Z","timestamp":1784102420000},"page":"e21357","source":"Crossref","is-referenced-by-count":0,"title":["Validity and reliability of the Valkyria Trainer Free\n                    <sup>\u00ae<\/sup>\n                    linear position transducer in the propulsive phase of bench press in men"],"prefix":"10.7717","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6871-098X","authenticated-orcid":true,"given":"\u00c1lvaro","family":"Huerta Ojeda","sequence":"first","affiliation":[{"name":"N\u00facleo de Investigaci\u00f3n en Salud, Actividad F\u00edsica y Deporte ISAFYD, Universidad de Las Am\u00e9ricas, Vi\u00f1a del Mar, Chile"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4913-9321","authenticated-orcid":true,"given":"Guillermo","family":"Barahona-Fuentes","sequence":"additional","affiliation":[{"name":"Faculty of Education and Social Sciences, Universidad Nacional Andres Bello, Vi\u00f1a del Mar, Chile"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rodrigo","family":"Beltr\u00e1n-Inostroza","sequence":"additional","affiliation":[{"name":"N\u00facleo de Investigaci\u00f3n en Salud, 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