20.500.12556/RUL-188622 Razlike v potenciacijskem učinku različnih tipov mišičnega naprezanja pri prvi ponovitvi vaje v seriji magistrsko delo Differences in the potentiating effect of different types of muscle contraction during the first repetition of an exercise set Metoda poudarjene ekscentrične obremenitve v prvi ponovitvi (PEO) vaje v seriji je nov pristop k vadbi za moč. Prva ponovitev, izvedena po tej metodi, pri kateri pri spustu bremena uporabimo večje breme kot pri dvigu in vseh naslednjih ponovitvah, naj bi izboljšala izvedbo nadaljnjih ponovitev v isti seriji. Namen raziskave je bil ugotoviti, kateri izmed tipov mišičnega naprezanja (ekscentrični, koncentrični, izometrični) v največji meri vpliva na mehanske spremenljivke nadaljnjih eksplozivnih koncentričnih ponovitev iztega kolena na trenažerju in na mehanske spremenljivke skrčka iztegovalk kolena. Izvedli smo sedem eksplozivnih koncentričnih ponovitev oziroma izzvali pet skrčkov v intervalu od 5 do 60 sekund po potenciacijskih protokolih. V raziskavi je sodelovalo 16 moških. V naključnem vrstnem redu smo izvedli štiri protokole (tri eksperimentalne in enega kontrolnega). Meritve smo izvedli na trenažerju za izteg kolena (enonožna izvedba). Učinek na eksplozivne koncentrične ponovitve smo ovrednotili na osnovi spremenljivk največjega navora, največjega prirastka navora v 100-ms intervalu, impulza navora v prvih 100 ms, indeksa moči, največjega prirastka amplitude EMG v 100-ms intervalu in prirastka amplitude EMG v prvih 100 ms. Učinek na skrčke smo ovrednotili na osnovi spremenljivk kontrakcijskega časa, amplitude skrčka, polovičnega relaksacijskega časa, amplitude M-vala in največje hitrosti prirastka navora skrčka. Rezultati eksplozivnih koncentričnih ponovitev niso pokazali razlik med tipi mišičnega naprezanja. Rezultati skrčkov so pokazali statistično značilne razlike med kontrolnim in eksperimentalnimi protokoli ter med eksperimentalnimi protokoli. Največje spremembe v primerjavi s kontrolnim pogojem so bile ugotovljene po izometričnem protokolu, in sicer pri spremenljivkah amplitude skrčka in največje hitrosti prirastka navora. Spremembe skrčka se ujemajo s pojavom poaktivacijske potenciacije (PAP). Rezultati ekscentričnega in koncentričnega protokola so bili podobni. Menimo, da je bil izometrični protokol najučinkovitejši zaradi specifičnosti gibalnega vzorca med potenciacijsko ponovitvijo in položajem, v katerem smo izmerili učinke na skrček (potenciacijsko ponovitev in meritve skrčkov smo izvedli na izometričen način pri 60° upogiba v kolenu). Ugotovitve kažejo, da tip predhodnega mišičnega naprezanja vpliva na izraženost PAP (na osnovi meritev mišičnega skrčka). Učinka na eksplozivne koncentrične ponovitve znotraj serije vadbe za moč v tej raziskavi ni bilo mogoče zanesljivo potrditi. First-repetition accentuated eccentric loading (FR-AEL) is a relatively new approach to resistance training. The first repetition performed using this method, in which a greater load is used during the lowering phase than during the lifting phase and all subsequent repetitions, is expected to improve the performance of subsequent repetitions within the same set. The purpose of this study was to determine which type of muscle contraction (eccentric, concentric or isometric) has the greatest effect on the mechanical variables of subsequent explosive concentric repetitions of knee extension on a resistance training machine and on the mechanical variables of knee extensor twitches. Seven explosive concentric repetitions were performed, or five twitches were elicited at intervals ranging from 5 to 60 seconds after the potentiation protocols. Sixteen men participated in the study. They completed four protocols (three experimental and one control) in a randomised order. Measurements were performed unilaterally on a leg extension machine. The effect on explosive concentric repetitions was evaluated on the basis of peak torque, maximal rate of torque rise over a 100 ms interval, torque impulse during the first 100 ms, power index, maximal rate of increase in EMG amplitude over a 100 ms interval and increase in EMG amplitude during the first 100 ms. The effect on twitches was evaluated based on contraction time, twitch amplitude, half-relaxation time, M-wave amplitude and maximal rate of twitch torque rise. The results for the explosive concentric repetitions showed no differences between the types of muscle contraction. The twitch results showed statistically significant differences between the control and experimental protocols and among the experimental protocols. The greatest changes compared with the control condition were observed following the isometric protocol, specifically in twitch amplitude and maximal rate of torque rise. The changes in the twitch response are consistent with the occurrence of post-activation potentiation (PAP). The results of the eccentric and concentric protocols were similar. We believe that the isometric protocol was the most effective because ofthe specificity of the movement pattern during the potentiating repetition and the position in which the effects on the twitch response were measured (the potentiating repetition and twitch measurements were performed isometrically at 60° of knee flexion). The findings indicate that the type of prior muscle contraction influences the magnitude of PAP (based on muscle twitch measurements). The effect on explosive concentric repetitions within a resistance training set could not be reliably confirmed in this study. poudarjena ekscentrična obremenitev ekscentrično naprezanje koncentrično naprezanje izometrično naprezanje skrček accentuated eccentric loading eccentric muscle contraction concentric muscle contraction isometric muscle contraction twitch true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-09-25 07:15:24 2026-09-25 07:15:58 2026-10-15 13:54:11 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 69803 301042179 35827.pdf 35827.pdf 1 CD4118358082A6795AAC4F649A68301C cfa0f72843a0626955dc5de142e33e67e0ad6b5be59a7774d4195e620b18a716 25150c07-b8a0-11f1-8bc5-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=248912 Fakulteta za šport 0 0 0