{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T05:41:36Z","timestamp":1786686096124,"version":"build-2736575974"},"reference-count":40,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2025,9,1]],"date-time":"2025-09-01T00:00:00Z","timestamp":1756684800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Muscles"],"abstract":"<jats:p>Isometric strength is widely used to monitor training adaptations, assess neuromuscular fatigue, and play a critical role in the maintenance of muscle health. This study assessed repeatability (intra-session) and reliability (inter-session) of a force production machine in different exercises: Isometric Mid-Thigh Pull (IMTP), Knee Flexion (KF) at 30\u00b0, and Seated Calf Raise (SCR). Parameters measured included Peak Force (PF), RFD at 0\u201350, 0\u2013100, 0\u2013150, 0\u2013200, 50\u2013100, 100\u2013150 and 150\u2013200 ms. Thirty male individuals (IMTP = 30; KF = 11 and SCR = 30) participated (age: 20.6 \u00b1 3.6 years, mass: 75.3 \u00b1 7.5 kg, height: 1.80 \u00b1 0.64 m). Repeatability and reliability were calculated for bilateral PF and RFD for IMTP and SCR, and unilateral for KF. PF demonstrated good to excellent repeatability in all exercises: IMTP (ICC = 0.93), KF (left: ICC = 0.98; right: ICC = 0.97), SCR (ICC = 0.84). RFD displayed poor to good repeatability in IMTP (ICC = 0.45\u20130.87) and SCR (ICC = 0.40\u20130.85), moderate to excellent repeatability in KF (left: ICC = 0.53\u20130.96; right: ICC = 0.61\u20130.92). PF reliability was excellent in IMTP (ICC = 0.93) and KF (left: ICC = 0.99; right: ICC = 0.97), and moderate in SCR (ICC = 0.64). RFD reliability was moderate to excellent in IMTP (ICC = 0.58\u20130.94), poor to good in SCR (ICC = 0.13\u20130.64), and poor to excellent in KF (left: ICC = 0.33\u20130.96; right: ICC = \u22120.19\u20130.95). This study shows that portable dynamometry can measure maximal and explosive strength in different exercises, demonstrating good reliability for most parameters in IMTP and KF.<\/jats:p>","DOI":"10.3390\/muscles4030036","type":"journal-article","created":{"date-parts":[[2025,9,2]],"date-time":"2025-09-02T08:23:38Z","timestamp":1756801418000},"page":"36","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["\u03c0Force\u2014Repeatability and Reliability of Peak Force and Rate of Force Development in a Portable Multi-Exercise Device"],"prefix":"10.3390","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0134-5038","authenticated-orcid":false,"given":"Ricardo","family":"Pimenta","sequence":"first","affiliation":[{"name":"Research Center in Sports Sciences, Health Sciences and Human Development (CIDESD), University of Maia, Av. Carlos de Oliveira Campos, Cast\u00ealo da Maia, 4475\u2013690 Maia, Portugal"},{"name":"Research Center of the Polytechnic Institute of Maia (N2i), Maia Polytechnic Institute (IPMAIA), Av. Carlos de Oliveira Campos, Cast\u00ealo da Maia, 4475\u2013690 Maia, Portugal"},{"name":"Department of Rehabilitation and Optimization of Performance (DROP), Futebol Clube Famalic\u00e3o\u2013Futebol SAD, Rua da Academia F.C. Famalic\u00e3o 300, Esmeriz, 4760-482 Famalic\u00e3o, Portugal"},{"name":"Porto Biomechanics Laboratory, Faculty of Sport, University of Porto, R. Dr. Pl\u00e1cido da Costa 91, 4200-450 Porto, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abel","family":"Pimenta","sequence":"additional","affiliation":[{"name":"Independent Researcher, Porto, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"702","DOI":"10.1016\/j.jsams.2021.02.007","article-title":"Considerations in Interpreting Neuromuscular State in Elite Level Australian Rules Football Players","volume":"24","author":"Norris","year":"2021","journal-title":"J. Sci. Med. Sport."},{"key":"ref_2","first-page":"145","article-title":"Impact of Post-Match Fatigue on Peak Force in Elite Youth Soccer Players: Analysis of 48 to 72 Hours Post-Match Using the Isometric Mid-Thigh Pull Exercise","volume":"42","author":"Pimenta","year":"2025","journal-title":"Biol. 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