{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T03:17:00Z","timestamp":1760239020126,"version":"build-2065373602"},"reference-count":24,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2020,9,16]],"date-time":"2020-09-16T00:00:00Z","timestamp":1600214400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004329","name":"Javna Agencija za Raziskovalno Dejavnost RS","doi-asserted-by":"publisher","award":["L5-1845","18-19-010","P5-0147"],"award-info":[{"award-number":["L5-1845","18-19-010","P5-0147"]}],"id":[{"id":"10.13039\/501100004329","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Rate of force\/torque development scaling factor (RFD-SF\/RTD-SF) was recently introduced as a tool to quantify the neuromuscular quickness, and it could have potential for interlimb asymmetry identification. Moreover, positive relationships in RFD-SF ability among different muscle groups were shown, but not in the lower extremity. The first aim of our study was to use RTD-SF for interlimb asymmetry identification. The second aim was to determine associations between plantar flexors (PF) and knee extensors (KE). Forty young healthy athletes (14.8 \u00b1 1.2 years) performed explosive isometric contractions to a span of torque levels for PF and KE. From rapid isometric contractions, the RTD-SF and linearity (r2) of the regression line were calculated. Using RTD-SF we identified 10% (PF) and 15% (KE) of subjects with contralateral asymmetries (&gt;15% criterion). The results revealed significant positive moderate correlation in RTD-SF between PF and KE (r = 0.401, p &lt; 0.05). We supported that RTD-SF can be a useful tool for interlimb asymmetry identification. Future research about observed asymmetry in rapid submaximal contractions deserves more attention, as most of the functional sport specific activities put high demands on rapid force production. Our study as first confirmed positive associations in RTD-SF ability between muscle groups in lower limbs.<\/jats:p>","DOI":"10.3390\/sym12091522","type":"journal-article","created":{"date-parts":[[2020,9,16]],"date-time":"2020-09-16T10:30:12Z","timestamp":1600252212000},"page":"1522","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Interlimb Asymmetries and Ipsilateral Associations of Plantar Flexors and Knee Extensors Rate-of-Force Development Scaling Factor"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5441-8988","authenticated-orcid":false,"given":"Darjan","family":"Smajla","sequence":"first","affiliation":[{"name":"Faculty of Health Sciences, University of Primorska, 6310 Izola, Slovenia"},{"name":"InnoRenew CoE, Livade 6, 6310 Izola, Slovenia"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8924-4420","authenticated-orcid":false,"given":"Olivera M.","family":"Knezevic","sequence":"additional","affiliation":[{"name":"Institute for Medical Research, University of Belgrade, 11000 Belgrade, Serbia"}]},{"given":"Dragan M.","family":"Mirkov","sequence":"additional","affiliation":[{"name":"The Research Centre, Faculty of Sport and Physical Education, University of Belgrade, 11030 Belgrade, Serbia"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0747-3735","authenticated-orcid":false,"given":"Nejc","family":"\u0160arabon","sequence":"additional","affiliation":[{"name":"Faculty of Health Sciences, University of Primorska, 6310 Izola, Slovenia"},{"name":"InnoRenew CoE, Livade 6, 6310 Izola, Slovenia"},{"name":"Andrej Maru\u0161i\u010d Institute, University of Primorska, 6000 Koper, Slovenia"},{"name":"S2P Science to Practice, Laboratory for Motor Control and Motor Behaviour, 1000 Ljubljana, Slovenia"}]}],"member":"1968","published-online":{"date-parts":[[2020,9,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Cafolla, D. (2019). A 3D visual tracking method for rehabilitation path planning. New Trends in Medical and Service Robotics, Mechanisms and Machine Science.","DOI":"10.1007\/978-3-030-00329-6_30"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1007\/s11465-015-0352-z","article-title":"An experimental characterization of human torso motion","volume":"10","author":"Cafolla","year":"2015","journal-title":"Front. Mech. Eng."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"19","DOI":"10.2165\/00007256-199622010-00003","article-title":"The use of isometric tests of muscular function in athletic assessment","volume":"22","author":"Wilson","year":"1996","journal-title":"Sport. Med."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1007\/s11999-009-0978-4","article-title":"Asymmetry in quadriceps rate of force development as a functional outcome measure in TKA","volume":"468","author":"Maffiuletti","year":"2010","journal-title":"Clin. Orthop. Relat. Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1701","DOI":"10.3389\/fphys.2018.01701","article-title":"Interlimb asymmetries identified using the rate of torque development in ballistic contraction targeting submaximal torques","volume":"9","author":"Boccia","year":"2018","journal-title":"Front. Physiol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1136\/bjsm.37.1.13","article-title":"Risk factors for lower extremity injury: A review of the literature","volume":"37","author":"Murphy","year":"2003","journal-title":"Br. J. Sports Med."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Casartelli, N.C., Item-Glatthorn, J.F., Friesenbichler, B., Bizzini, M., Salzmann, G.M., and Maffiuleti, N.A. (2019). Quadriceps neuromuscular impairments after arthroscopic knee surgery: Comparison between procedures. J. Clin. Med., 8.","DOI":"10.3390\/jcm8111881"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1080\/02640414.2016.1168933","article-title":"Contralateral limb deficit after ACL-reconstruction: An analysis of early and late phase of rate of force development","volume":"35","author":"Mirkov","year":"2017","journal-title":"J. Sports Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1039","DOI":"10.1016\/j.knee.2014.07.021","article-title":"Asymmetries in explosive strength following anterior cruciate ligament reconstruction","volume":"21","author":"Knezevic","year":"2014","journal-title":"Knee"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"329","DOI":"10.1136\/bjsports-2017-098101","article-title":"Isokinetic strength assessment offers limited predictive validity for detecting risk of future hamstring strain in sport: A systematic review and meta-analysis","volume":"52","author":"Green","year":"2018","journal-title":"Br. J. Sports Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"S11","DOI":"10.1055\/s-2007-1021104","article-title":"Isokinetic evaluation of muscular performance","volume":"15","author":"Kannus","year":"1994","journal-title":"Int. J. Sports Med."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2044","DOI":"10.1249\/mss.0b013e31814fb55c","article-title":"A vertical jump force test for assessing bilateral strength asymmetry in athletes","volume":"39","author":"Impellizzeri","year":"2007","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1553","DOI":"10.1519\/JSC.0b013e3181dc4392","article-title":"A comparison of isokinetic and functional methods of assessing bilateral strength imbalance","volume":"24","author":"Jones","year":"2010","journal-title":"J. Strenght Cond. Res."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"359","DOI":"10.1007\/s00221-011-2735-7","article-title":"The rate of force development scaling factor (RFD-SF): Protocol, reliability, and muscle comparisons","volume":"212","author":"Bellumori","year":"2011","journal-title":"Exp. Brain. Res."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"015001","DOI":"10.1088\/1361-6579\/aa9f51","article-title":"Methodological considerations in the calculation of the rate of force development scaling factor","volume":"39","author":"Djordjevic","year":"2017","journal-title":"Physiol. Meas."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"932","DOI":"10.1002\/mus.24229","article-title":"Assessment of the rate of force development scaling factor for the hip muscles","volume":"50","author":"Casartelli","year":"2014","journal-title":"Muscle Nerve"},{"key":"ref_17","first-page":"22","article-title":"Reliability of maximal voluntary contraction related parameters measured by a novel portable isometric knee dynamometer","volume":"23","author":"Sarabon","year":"2013","journal-title":"Phys. Medizin. Rehabil. Kurortmed."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1249\/MSS.0b013e31818cb278","article-title":"Progressive statistics for studies in sports medicine and exercise science","volume":"41","author":"Hopkins","year":"2009","journal-title":"Med. Sci. Sport. Exerc."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/BF00235800","article-title":"The relationship between speed and amplitude of the fastes voluntary contracitons of human arm muscles","volume":"31","author":"Freund","year":"1978","journal-title":"Exp. Brain Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"370","DOI":"10.1123\/mcj.17.4.370","article-title":"Age-related decline in the rate of force development scaling factor","volume":"17","author":"Bellumori","year":"2013","journal-title":"Mot. Control"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1093\/brain\/91.1.15","article-title":"The functional organization of the motor system in the monkey. II. The effects of lesions of the descending brain-stem pathways","volume":"91","author":"Lawrence","year":"1968","journal-title":"Brain"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Suzuki, T., Kinugasa, R., and Fukashiro, S. (2017). Activation of plantar flexor muscles is constrained by multiple muscle synergies rather than joint torques. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0187587"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"602","DOI":"10.14740\/jocmr2107w","article-title":"Knee and ankle joint angles influence the plantarflexion torque of the gastrocnemius","volume":"7","author":"Landin","year":"2015","journal-title":"J. Clin. Med. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1007\/BF01003594","article-title":"Muscle fibre type populations of human leg muscles","volume":"7","author":"Edgerton","year":"1975","journal-title":"Histochem. J."}],"container-title":["Symmetry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-8994\/12\/9\/1522\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T10:10:21Z","timestamp":1760177421000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-8994\/12\/9\/1522"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,9,16]]},"references-count":24,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2020,9]]}},"alternative-id":["sym12091522"],"URL":"https:\/\/doi.org\/10.3390\/sym12091522","relation":{},"ISSN":["2073-8994"],"issn-type":[{"type":"electronic","value":"2073-8994"}],"subject":[],"published":{"date-parts":[[2020,9,16]]}}}