{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T11:00:15Z","timestamp":1789815615460,"version":"4.0.1"},"reference-count":21,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,1,17]],"date-time":"2022-01-17T00:00:00Z","timestamp":1642377600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Translational R&amp;D Program on Smart Rehabilitation Exercises, National Rehabilitation Center, Ministry of Health and Welfare, Korea","award":["#TRSRE-MD02"],"award-info":[{"award-number":["#TRSRE-MD02"]}]},{"name":"Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education","award":["2020R1I1A3A04038203"],"award-info":[{"award-number":["2020R1I1A3A04038203"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>1-repetition maximum (1RM), a representative index for an individual\u2019s weightlifting capacity, provides an organized workout guide, but to measure 1RM needs several repetitive exercises up to one\u2019s limit and has a risk of injury, thus, not adequate for beginners, elders, or disabled people. This study suggests a simpler and safer 1RM measurement method using a hydraulic fitness machine. We asked twenty-five female subjects with less than a month of experience in weight training to repeat chest exercises using a conventional plate-loaded bench press machine and a hydraulic bench press machine and measured 1RMs. Repeated-measures ANOVA and paired t-test reported the difference between the plate and hydraulic 1RMs insignificant (p-value = 0.082) and confirmed the generality of 1RM across the different types of fitness machines. We then derived several 1RM equations in terms of load weight W and lifting speed v during non-1RM exercise and reduced it to a first-order polynomial expression 1RM=\u22120.3908+0.8251W+0.1054v with adjusted R-square of 0.8849. Goodness-of-fit test and comparison with 1RM equations from reference studies (v=\u22121.46\u00d7W1RM+1.7035,\u00a0W1RM\u00d7100=7.5786v2\u221275.865v+113.02) verified our formula valid. We finally simplified the 1RM measurement process up to a maximum of three repetitions.<\/jats:p>","DOI":"10.3390\/s22020698","type":"journal-article","created":{"date-parts":[[2022,1,17]],"date-time":"2022-01-17T20:49:21Z","timestamp":1642452561000},"page":"698","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Estimation of 1-Repetition Maximum Using a Hydraulic Bench Press Machine Based on User\u2019s Lifting Speed and Load Weight"],"prefix":"10.3390","volume":"22","author":[{"given":"Jinyeol","family":"Yoo","sequence":"first","affiliation":[{"name":"Department of Advanced Convergence, BK21 FOUR, Handong Global University, Pohang 37554, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jihun","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Control Engineering, Handong Global University, Pohang 37554, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Byunggon","family":"Hwang","sequence":"additional","affiliation":[{"name":"Department of Advanced Convergence, BK21 FOUR, Handong Global University, Pohang 37554, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gyuseok","family":"Shim","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Control Engineering, Handong Global University, Pohang 37554, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0523-8304","authenticated-orcid":false,"given":"Jaehyo","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Control Engineering, Handong Global University, Pohang 37554, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,17]]},"reference":[{"key":"ref_1","unstructured":"(2021, November 17). 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