Isometric contraction
Dotaz
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- MeSH
- elektroencefalografie MeSH
- lidé MeSH
- mozek fyziologie MeSH
- svalová kontrakce MeSH
- svaly fyziologie MeSH
- Check Tag
- lidé MeSH
V simulační studii (ve výukovém referátu) je po stručném fyziologickém úvodu popsán lineární model izometrické kontrakce kosterního svalu pomocí mechanické analógie. Model se skládá z bloků, z nichž první, generující sílu, představuje kontraktilní aparát a další modelují plastické a elastické vlastnosti svalu na základě pružin a elementů viskozního třeni Platnost modelu je omezena pouze na okolí pracovního bodu činnosti svalu. Výsledky simulace vyjadřují grafy, charakterizující průběh koncentrace vápníkových iontů ve svalu, průběh síly generované svalem a srovnání průběhů této silypři různých periodách budicího signálu. Simulace probíhá v simulačním prostředí MATLAB - SIMULINK, jež tvoří základ výukového simulačního systému, využívaného při výuce předmětu Biokybernetika na katedře kybernetiky FEL, ČVU T v Praze.
After a brief physiological introduction a skeletal nuscle isometric contraction linear model using mezhanical analogy is described in the simulation study. The model consists of blocks; the first of them generaIng force, represents contractile apparatus and the text ones model plastic and elastic muscle qualities on the basis of springs and viscous friction elements. Model validity is limited only on muscle activity working point enviroment The simulation results are presented by graphs characterizing calcium ions in the nuscle concentration course, force generated by muscle course and comparizon of this force courses during various periods of exciting signal The simulation is performed in the MATLAB - SIMULINK environment making the bases of the educational simulation system used by teaching the subject Biocybernetics on the Department of Cybernetics of the Faculty of Electrical Engineering Czech Technical University in Prague.
Autorka přináší pohled fyziologa na problém excentrické kontrakce. Připomíná, že ačkoliv koncen- trickým a izometrickým kontrakcím byly věnovány četné vědecké práce, excentrická kontrakce stála stranou zájmu fyziologů i biomechaniků. Autorka shrnuje poznatky sporadických studií a interpretuje záznamy EMG studií. V závěru uvádí praktické důsledky porozumění mechanismu excentrické kontrakce.
The author deals from the physiologists aspect with the problem of excentric contraction. She reminds, that although many scientific publications are devoted to concentric and isometric contrac- tions, excentric contractions are still on the border of interest of physiologists and biomechanists. The author summarizes the findings of sporadic studies and interprets the record of EMG studies. In the conclusion she outlines practical outcomes of the understanding of the mechanism of excentric contraction.
- MeSH
- elektromyografie MeSH
- isometrická kontrakce MeSH
- kinezika MeSH
- lidé MeSH
- postura těla MeSH
- svalová kontrakce MeSH
- Check Tag
- lidé MeSH
Práca predkladá teoretické poznatky o využití izometrických cvičení v širokom spektre liečebnei rehabilitácie, ich indikácie, kontraindikácie, správnu metodiku cvičenia a očakávaný prínos pre pacienta a praktické skúsenosti získané na klinickom pracovisku sledovaním súboru 14 pacientov v období 4 týždňov komplexnej rehabilitačnej liečby so zameraním na vplyv izometrických cvičení na svalovú silu, nárast svalovej hmoty a redukciu bolesti.
The paper presents theoretical knowledge on isometric exercises use in wide range of therapeutic rehabilitation procedures, their indications, and contraindications. The paper also describes correct method of isometric exercises, expected contribution to patient, and practical experience acquired on rehabilitation department. We followed up a cohort of 14 patients for period of 4 weeks with complex rehabilitation. We evaluated effect of isometric exercises on muscle strength, increase of muscle mass, and reduction of pain.
- MeSH
- isometrická kontrakce MeSH
- lidé MeSH
- rehabilitace metody MeSH
- techniky cvičení a pohybu MeSH
- Check Tag
- lidé MeSH
The aim of this study was to compare the effects of 3 sets of isometric conditioning activity (ICA), each with an equal total duration (9 s per set) but with different distributions contractions, on force production during ICA and subsequent countermovement jump (CMJ) performance. Fifteen resistance-trained males participated in this study (age: 22.1 ± 2.4 years; body mass: 85.1 ± 9.7 kg; height: 181.3 ± 6.5 cm; relative one-repetition maximum (1RM) in back squat: 1.59 ± 0.32 kg/kg of body mass). Participants completed 3 conditions, each consisting of ICA in the half-back squat with a pushing isometric muscle action (PIMA) position at a 120-degree knee angle against an immovable barbell, differing in repetition distribution: 3 sets of 9 repetitions lasting 1 s each (SUST-1), 3 sets of 3 repetitions lasting 3 s each (SUST-3), 3 sets of single repetitions lasting 9 s (SUST-9), and a control condition (CTRL) without ICA. A 1-minute rest was allowed between sets. Approximately 3 min pre-ICA and at 15 s, 3-, 6-, 9-, and 12-minutes post-ICA, the CMJ performance was assessed. Moreover, peak force (PF) production, and force generated at 100 (Force100) and 200 ms (Force200) during each ICA were evaluated. A two-way repeated measures ANOVA indicated a main effect of time on CMJ height (F = 2.674; p = 0.029; ηp2=0.171) but did not show significant differences between conditions (F = 0.934; p = 0.434; ηp2=0.067) or interactions (F = 0.826; p = 0.648; ηp2=0.060). Post-hoc comparisons indicated a significant decrease in CMJ height at the 9th minute compared to the 3rd minute (35.7 ± 5.6 cm vs. 36.8 ± 5.5 cm post-CA; d = 0.161; p = 0.048). In addition, no significant interactions or main effects were found for CMJ contraction time, PF and Force100 during ICA. However, a main effect of condition was demonstrated on Force200 (F = 19.181; p < 0.001; ηp2= 0.013). Post-hoc comparisons revealed higher Force200 values in SUST-1 (mean difference [MD] = 549 ± 137 N; d = 1.049; p < 0.001) and SUST-3 (MD = 348 ± 112 N; d = 0.665; p = 0.002) compared to the SUST-9 condition. None of the ICAs used in the present study had any effect on the CMJ performance. However, the significantly higher Force200 values noted in the SUST-1, and SUST-3 conditions compared to the SUST-9 condition suggest that the specific distributions of isometric contraction influence the force generated during their execution.
- MeSH
- dospělí MeSH
- isometrická kontrakce * fyziologie MeSH
- kosterní svaly * fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- odporový trénink * metody MeSH
- sportovní výkon * fyziologie MeSH
- svalová síla fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
100 rats were randomly divided into a sham-operated group and middle cerebral artery occlusion (MCAO) modeling groups. The sham group after surgery was observed for 14 days. After MCAO, some rats received isometric contraction training (ICT) which was as follows: an atraumatic tourniquet was placed around left or right hind limb to achieve hind limb ischemia for 5 min, followed by 5 min of reperfusion, 4 cycles for one time, once a day, and five days per week. The MCAO modeling groups included the following four groups: i) a group only received MCAO, and was observed for seven days (MCAO-7d), ii) a group only received MCAO, and was observed for 14 days (MCAO-14d), iii) a group, after MCAO, received ICT for seven days (ICT-7d), and iv) a group, after MCAO, received ICT for 14 days (ICT-14d). Brain infarct area, behavioral outcomes, the number of neurons, apoptosis, cerebral edema and cerebral water content were assessed, respectively. The mRNA expression of vascular endothelial growth factor (VEGF) was assayed with RT-PCR, and protein expression of VEGF was quantified with western blot. compared with MCAO controls, cerebral infarction, neurological deficits and neuronal apoptosis were reduced significantly in the ICT groups, while the number of neurons was increased. Moreover, the mRNA expression of VEGF and protein expression of VEGF were enhanced after 1 and 2 weeks of ICT. ICT may promote angiogenesis and neuroprotection after ischemic stroke and this new remodeling method provide a novel strategy for rehabilitation of stroke patients.
- MeSH
- cévní mozková příhoda * terapie MeSH
- infarkt arteria cerebri media MeSH
- ischemie mozku * metabolismus MeSH
- isometrická kontrakce * MeSH
- kondiční příprava zvířat * MeSH
- krysa rodu rattus MeSH
- messenger RNA MeSH
- modely nemocí na zvířatech MeSH
- neuroprotekce MeSH
- potkani Sprague-Dawley MeSH
- vaskulární endoteliální růstový faktor A metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
