izpis_h1_title_alt

Merjenje nivoja mišične aktivacije z metodo primerjave največje izometrične in eksentrične sile : doktorska disertacija
ID Umer, Romina (Author), ID Strojnik, Vojko (Mentor) More about this mentor... This link opens in a new window

.pdfPDF - Presentation file, Download (4,43 MB)
MD5: 9B56F62480F118D9DDAE3C7B3BC76128

Abstract
Cilj naloge je bil preveriti uporabnost meritve nivoja mišične aktivacije (NA) s primerjavo največjega izometričnega in ekscentričnega navora (metoda razmerij navorov – MRN), izmerjenega s pomočjo enostavnega hidravličnega sistema domače izdelave, vgrajenega v trenažer za izteg kolen. Rezultate, dobljene z MRN, smo primerjali s tistimi, dobljenimi z že uveljavljeno metodo dvojnega vrinjenega skrčka (MDS). V ta namen smo želeli ugotoviti zanesljivost in občutljivost meritev ter njihovo veljavnost v pogojih akutnih (utrujanje) in kroničnih (vadba za moč) vplivov na NA. V raziskavi je prostovoljno sodelovalo 28 rekreativno treniranih merjencev moškega spola (povprečna starost in standardni odklon 30,3 ± 10,6 let, telesna višina 181,6 ± 8,0 cm, telesna masa 83,6 ± 9,7 kg). Raziskava je potekala v dveh delih. V prvem delu je 9 merjencev znotraj merilnega dneva opravilo 2 meritvi NA z obema metodama (2 ponovitvi za vsako metodo, vrstni red je bil naključno izbran), nato je sledil protokol utrujanja, ki je vseboval 2-min zadrževanje največjega hotenega izometričnega naprezanja. Takoj zatem so merjenci ponovno opravili po 2 meritvi NA z vsako metodo (isti vrstni red). V drugem delu je bilo vključenih 6 merjencev eksperimentalne skupine (ES) in 6 kontrolne skupine (KS), ki so znotraj merilnega dneva po naključnem vrstnem redu izvedli po 2 meritvi NA z MRN in 1 meritev z MDS. Opravili so začetne (ZM) in končne (KM) meritve. Med merilnima dnevoma je ES izvajala 4-tedenski program vadbe za razvoj mišične aktivacije, medtem ko je KS opravljala običajne aktivnosti. Pri posamezni meritvi z MRN sta bila izmerjena največji hoteni izometrični navor v kotu v kolenu 60° in v isti gibalni akciji največji hoteni ekscentrični navor v amplitudi od 55° do 70° iztega kolena, ki ga je omogočil hidravlični sistem med potiskom vzvoda trenažerja s konstantno hitrostjo 35°/s do 65°/s. NA, izmerjen z MRN (NA_MRN), je bil izračunan kot razmerje med največjim hotenim izometričnim in ekscentričnim navorom. Meritev z MDS je bila opravljena na izometričnem dinamometru za izteg kolen, kjer smo s pomočjo tokovno konstantnega električnega stimulatorja preko površine kože na trebuhu mišice stimulirali štiriglavo stegensko mišico z dvojnim supramaksimalnim električnim dražljajem (dvofazni impulz trajanja 0,3 ms, interval med impulzoma 10 ms). NA, izmerjen z MDS (NA_MDS), je bil izračunan na osnovi primerjave velikosti skrčka med največjim hotenim izometričnim naprezanjem in takoj po njem, ob sproščeni mišici, v kotu 60° iztega kolena. Rezultati meritev z MRN v izhodiščnem stanju (spočitost merjencev, meritve, izvedene pred obema intervencijama) so pokazali odlično ponovljivost za vse obravnavane spremenljivke (ICC > 0,90; p < 0,001). Primerjava znotraj merilnega dneva ni pokazala razlik med metodama v povprečnih vrednostih največjih hotenih izometričnih navorov, izmerjenih v izhodiščnem stanju in po protokolu utrujanja, s srednje visokimi do visokimi korelacijskimi koeficienti (0,60 > r > 0,94; p > 0,05). Vadba za moč ni prinesla pričakovanih rezultatov, saj med ZM in KM nismo ugotovili razlik v izmerjenih vrednostih največjih hotenih izometričnih navorov za obe skupini kot tudi ne med skupinama (p > 0,05). Kljub visokim korelacijam med metodama v največjih hotenih izometričnih navorih primerjava povprečnih vrednostih NA, izmerjenih v vseh treh stanjih (i – spočito, ii – po protokolu utrujanja ter iii – po vadbi), ni pokazala značilnega ujemanja med metodama, saj so se vrednosti med seboj razlikovale (p < 0,05), korelacije pa so bile neznatne, negativne in neznačilne (-0,10 < ICC < 0,20). Ugotovili smo, da uporaba hidravličnega sistema za merjenje NA z MRN, ki smo ga uporabili v nalogi, ne daje rezultatov, primerljivih z MDS.

Language:Slovenian
Keywords:deficit sile, hidravlični sistem, dvojni vrinjeni skrček, ICC, veljavnost
Work type:Doctoral dissertation
Typology:2.08 - Doctoral Dissertation
Organization:FŠ - Faculty of Sport
Year:2019
PID:20.500.12556/RUL-113533 This link opens in a new window
COBISS.SI-ID:5661617 This link opens in a new window
Publication date in RUL:17.01.2020
Views:1947
Downloads:308
Metadata:XML RDF-CHPDL DC-XML DC-RDF
:
Copy citation
Share:Bookmark and Share

Secondary language

Language:English
Title:Measurement of muscle activation level with comparing the maximum torques during isometric and eccentric contraction
Abstract:
The aim of the study was to verify the usefulness of the measurement of muscle activation level (AL) by comparing the maximal isometric and eccentric torque (torques ratio method - TRM), measured using a simple home-made hydraulic system built into the leg extension machine. The results obtained with TRM were compared with those measured with the already established double-interpolated twitch method (DTM). At this purpose, we wanted to determine the reliability and sensitivity of measurements and their validity under conditions of acute (fatigue) and chronic (strength training) effects on the AL. 28 recreational trained male subject (average age and standard deviation 30,3 ± 10,6 years, height 181,6 ± 8,0 cm, body mass 83,6 ± 9,7 kg) voluntarily participated in the study. The research was conducted in two parts. In the first part, 9 subjects within the measurement day performed 2 measurement of AL on both method (2 repetitions for each method, order was randomly selected), followed by a fatigue protocol containing 2-min maximal voluntary contraction. Immediately afterwards, subjects repeated 2 measurements of NA for each method (in the same order). The second part included 6 subject of experimental group (EG) and 6 of control group (CG). They performed within the measurement day in random order 2 repetition of AL measurement with TRM and 1 with DTM. Initial (IM) and final (FM) measurements were performed. Between the measurement days, EG performed a 4-week exercise program for the development of AL, while CG performed daily activities. For single measurement of the TRM, the maximal voluntary isometric torque in the knee angle 60° was measured first, followed, in the same movement action, by the measurement of maximal voluntary eccentric torque in the range of motion from 55° to 70° of knee extension, made possible by the hydraulic sistem while pushing the trainer lever at the constant angle velocity 35°/s to 65°/s. AL, measured with TRM (AL_TRM) was then calculated as a ratio between maximum voluntary isometric and eccentric torque. Measurement with DTW were performed on an isometric dynamometer for leg extension. When measured with DTW, the muscle quadriceps femoris was stimulated across the surface of the skin on the belly of the muscle by a double-superimposed, supramaximal electrical stimulus (two-phase pulse duration 0,3 ms, interval between pulses 10 ms). AL, measured with DTW (AL_DTW) was obtained with comparing the twitch amplitude superimposed on maximal voluntary isometric contraction and the twitch amplitude of the relaxed muscle immediately after it at the knee angle 60° of knee extension. The results of the MRN measurements at baseline (restfulness of subjects, measurements taken before both interventions) showed excellent repeatibility for all variables (ICC > 0,90; p < 0,001). Comparison within the measurement day showed no differences between the methods in the mean values of the maximum voluntary isometric torques, measured at baseline and after fatigue protocol, with medium to high correlation coefficients (0,60 > r > 0,94; p > 0,05). Strength training did not produce the expected results, as we did not find differences between the IM and FM in measured values of maximum voluntary isometric torques for the two groups, as well as between the groups (p > 0,05). Despite the high correlations between the methods in the maximum torque isometric torques, the comparison of the average NA values measured in all three conditions (i - restful, ii - after fatigue protocol and iii - after exercise) did not show significant match between the methods, since the values differed (p < 0,05) and the correlations were low, negative and nonsignificant (-0,10 > ICC < 0,20). We found that the use of a hydraulic system for measuring AL with TRM does not provide comparable results with the DTW.

Keywords:strength deficit, hydraulic system, double interpolated twitch method, ICC, validity

Similar documents

Similar works from RUL:
Similar works from other Slovenian collections:

Back