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3. Effects of eccentric training at long muscle length on architectural and functional characteristics of the hamstringsJan Marušič, Rok Vatovec, Goran Marković, Nejc Šarabon, 2020, original scientific article Abstract: Hamstring strain injuries during sprinting or stretching frequently occur at long-muscle length. Yet, previous research has mainly focused on studying the effectiveness of eccentric hamstring strengthening at shorter muscle length on hamstring performance, morphology, and hamstring strain injury risk factors. Here, we evaluated the effects of 6-week eccentric hamstring training at long-muscle length on functional and architectural characteristics of the hamstrings. Healthy and injury-free participants (n = 40; age 23.7 % 2.5 years) were randomly assigned to control or intervention group. Training intervention consisted of 12 sessions with two eccentric hamstring exercises in a lengthened position. Outcome measures included isokinetic and isometric knee flexion peak torque, Nordic hamstring exercise peak torque, voluntary activation level, and countermovement jump performance. Ultrasonography was used to determine muscle thickness, pennation angle, and fascicle length of biceps femoris long head (BFlh). A significant time % group interaction effect was observed for all measured parameters except countermovement jump performance and muscle thickness. The training intervention resulted in increased concentric and eccentric knee flexion peak torque at 60°/s (d = 0.55-0.62, P = .02 and .03) and concentric peak torque at 180°/s (d = 0.99, P = .001), increased isometric knee flexion peak torque (d = 0.73, P = .008) and Nordic hamstring exercise peak torque (d = 1.19, P < .001), increased voluntary activation level (d = 1.29, P < .001), decreased pennation angle (d = 1.31, P < .001), and increased fascicle length (d = 1.12, P < .001) of BFlh. These results provide evidence that short-term eccentric hamstring strengthening at long-muscle length can have significant favorable effects on various architectural and functional characteristics of the hamstrings. Keywords: biceps femoris, fascicle length, knee flexion torque, pennation angle, strength Published in RUP: 07.08.2020; Views: 2212; Downloads: 61 Link to full text |
4. Introduction of dynamic rate-of-force development scaling factor in progressive drop jumpsNejc Šarabon, Olivera M. Knezevic, Dragan Mirkov, Darjan Smajla, 2020, original scientific article Abstract: Rapid force generation across submaximal levels has been evaluated with the rate of force development scaling factor (RFD-SF) in different isometric tasks, while such measurement was still not verified in dynamic tasks. Our study was designed to evaluate the feasibility of the RFD-SF in dynamic drop jump (DJ) task (RFD-SFDJ). A total of 55 young athletes performed isometric plantarflexion at different submaximal intensities and 60 DJs (6 different drop heights). For each participant we calculated linearity (r2 ) and slope in isometric task (RFD-SFPF), eccentric part of DJ (RFD-SFDJ-ECC) and concentric part of DJ (RFD-SFDJ-CON), as well as average jump height (DJH) from each drop height. Our results revealed strong linear force-RFD relationship for isometric plantarflexion (r2 = 0.90 % 0.06), eccentric (r2 = 0.87 % 0.09) and concentric phase of DJ (r2 = 0.80 % 0.18). Significant moderate positive correlations were calculated between RFD-SFPF and RFD-SFDJ-ECC (r = 0.311, p < 0.05) and small negative correlations between RFD-SFDJ-CON and RFD-SF (r = -0.276, p < 0.05). Significant positive moderate correlations were seen only between RFD-SFDJ-ECC and DJH from 10 cm (r = 0.459, p < 0.001) and 15 cm (r = 0.423, p < 0.01). This is the first study to introduce and confirm that RFD-SFDJ can be obtained from the multi-joint tasks (60 jumps) and still provide acceptable reliability and linear relationship. Furthermore, RFD-SFDJ may have greater practical application than RFD-SF assessed under the isometric conditions. This verification of RFD-SFDJ opens opportunities for further research regarding its practical application. Keywords: explosive strength, stretch-shortening cycle, plyometric, ankle, isometric Published in RUP: 07.08.2020; Views: 2043; Downloads: 71 Link to full text |
5. Fatigue behavior of beech and pine wood modified with low molecular weight phenol-formaldehyde resinJaka Gašper Pečnik, Andreja Kutnar, Holger Militz, Matthew Schwarzkopf, Hannes Schwager, 2020, original scientific article Keywords: beech, creep rate, fatigue strength, phenol formaldehyde, pine, stress level, wood modification Published in RUP: 02.07.2020; Views: 1592; Downloads: 53 Link to full text |
6. Reliability assessment of confinement models of carbon fiber reinforced polymer-confined concreteLiang Huang, Chang Gao, Libo Yan, Bohumil Kasal, Gao Ma, 2016, original scientific article Keywords: concrete, carbon fiber-reinforced polymer, confinement, strength model, database, reliability analysis Published in RUP: 19.11.2018; Views: 1834; Downloads: 236 Link to full text |
7. Engineered bamboo scrimber: Influence of density on the mechanical and water absorption propertiesAnuj Kumar, Tomáš Vlach, Lenka Laiblová, Martin Hrouda, Bohumil Kasal, Jan Tywoniak, Petr Hajek, 2016, original scientific article Keywords: biocomposite, mechanical properties, strength, ultrasonics, bamboo scrimber Published in RUP: 19.11.2018; Views: 1780; Downloads: 357 Link to full text |
8. Effects of feedback-based balance and core resistance training vs. Pilates training on balance and muscle function in older women : a randomized-controlled trialGoran Marković, Nejc Šarabon, Zrinka Greblo, Valerija Križanić, 2015, original scientific article Keywords: posturalni nadzor, mišična jakost, gibalna zmogljivost, vadba, trening, postural control, muscle strength, physical performance, exercise training Published in RUP: 03.04.2017; Views: 3039; Downloads: 81 Link to full text |
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10. The history, theory and practice of restricted blood flow resistance training (RBFRT/KAATSU)Armin Paravlić, Stefan Đorđević, Raid Mekić, Adem Mavrić, 2015, published scientific conference contribution Keywords: KAATSU, RBFRT, restricted blood flow, occlusion, resistance training, strength, muscle mass, hypertrophy, effects Published in RUP: 08.08.2016; Views: 3997; Downloads: 50 Link to full text |