Akutni nevrofiziološki odzivi na izometrično vadbo za moč z neprekinjeno in prekinjeno okluzijo

Bevc, Jaka (author), Štirn, Igor (mentor), Debevec, Tadej (comentor)

Namen magistrske naloge je bil izmeriti akutne nevrofiziološke odzive na izometrično vadbo z neprekinjeno in prekinjeno okluzijo ter jih primerjati z vadbo brez okluzije. V raziskavi je sodelovalo trinajst (21,1 ± 3,0 let, 184,9 ± 7,2 cm, 81,4 ± 9,1kg) redno telesno aktivnih moških. Tri meritve so bile izvedene v obdobju 14. dni. Na vseh meritvah so izvajali enak test v enakih pogojih, spreminjala se je le uporaba okluzije med vadbo. Enkrat so izvajali izometrično vadbo brez okluzije, enkrat s prekinjeno okluzijo in enkrat z neprekinjeno okluzijo. Izvajali so izometrično vadbo 3 serije po 60 s pri 40% NHIK (največje hotene izometrične kontrakcije). Pred, med in po vadbi so bile izvedene meritve NHIK, mehanskih odzivov na enojne supramaksimalne električne dražljaje (skrčke), EMG (elektromiografija) in subjektivne ocene napora z Borgovo lestvico (6-20). Iz izmerjenih EMG signalov smo ugotovili vrednosti srednje frekvence močnostnega spektra (SMF), mediane frekvence močnostnega spektra (MMF) in koren povprečne kvadratne vrednosti (RMS – root mean square value). Izračunali smo tudi % regeneracije med serijami na podlagi skrčkov. Učinki prekinjene in neprekinjene okluzijske vadbe ter izometrične vadbe brez okluzije so podobni pri upadu NHIK po vadbi, zmanjšanju SMF in MMF med serijami, povečanju RMS med in znotraj serij ter upadu navora potenciranega skrčka. Razlikujejo se le pri upadu navora skrčka po koncu serij (p < 0,001), regeneraciji navora skrčka v 2. (p = 0,001) in 3. (p = 0,037) seriji ter povečanju občutka subjektivnega napora v 2. (p = 0,008) in 3. (p < 0,001) seriji. Navor skrčka se po koncu serij bolj zmanjša pri vadbah z okluzijo, kot pri vadbi brez okluzije, kar nakazuje na večjo periferno utrujenost, ki je preko sekundarnih mehanizmov povezana s hipertrofičnim odzivom. Subjektivni občutek napora je najvišji pri neprekinjeni vadbi z okluzijo ter podoben pri vadbi brez okluzije in prekinjeni vadbi z okluzijo. Dobljeni rezultati kažejo, da pri vseh oblikah vadbe pride do podobnih akutnih odzivov, z možnim večjim vplivom na periferno utrujenost pri vadbah z okluzijo. Ti odzivi lahko preko sekundarnih mehanizmov vplivajo na hipertrofijo. Ker pa je vadba s prekinjeno okluzijo bolj prijetna in se pri njej občuti manj neugodja, priporočamo njeno uporabo namesto vadbe z neprekinjeno okluzijo.

• Language: Slovenian
• Keywords: vadba z okluzijo, izometrična vadba, elektromiografija, subjektivna ocena napora
• Work type: Master's thesis/paper
• Organization: FŠ - Faculty of Sport
• Year: 2024
• PID: 20.500.12556/RUL-159490
• Publication date in RUL: 11.07.2024

Secondary language

• Language: English
• Title: Acute neurophysiological effects of isometric strength training with continuous and intermittent blood flow restriction

Abstract

The purpose of this Master's thesis was to determine the acute neurophysiological effects of isometric strength training with blood flow restriction (BFR). Thirteen physically active men (21,1 ± 3,0 years 184,9 ± 7,2 cm, 81,4 ± 9,1kg) performed three different training sessions. On each visit they performed the same tests under the same conditions, the only variable was the training method. One time they trained without BFR, one time with intermittent BFR, and one time with continuous BFR. They performed 3 sets of isometric unilateral knee extensions at 40% maximum voluntary contraction (MVC). Measurements of different variables were performed before, during, and after exercise. Those included, MVC, electrically evoked twitch torque, electromyography (EMG), and rate of perceived exertion (RPE). Mean frequency (MNF), median frequency (MDF), and root mean square (RMS) were extracted from raw EMG data. Recovery (%) between sets was calculated from the change of electrically evoked twitch torque. The effects of continuous BFR and intermittent BFR, as well as isometric exercise without BFR, exhibit similarities in terms of post-exercise neuromuscular fatigue, reduction in MVC, decrease in SMF and MMF between sets, rise in EMG activity (RMS) between and within sets, decreased potentiated twitch torque. However, they differ significantly in the reduction of twitch torque after the completion of sets (p = 0.000), the regeneration of twitch torque in the 2nd (p = 0.001) and 3rd (p = 0.037) set, and the RPE in the 2nd (p = 0.008) and 3rd (p = 0.000) set. Twitch torque reduction after sets is greater in exercises with BFR, compared to non-BFR exercise, indicating greater peripheral fatigue which is associated with hypertrophic responses through secondary mechanisms. The RPE is highest during intermittent BFR and similar between non-BFR and intermittent BFR exercise. Based on the obtained results, we conclude that all forms of exercise elicit similar responses, with a potentially greater impact on peripheral fatigue in BFR exercises. These responses may influence hypertrophy through secondary mechanisms. Considering that intermittent BFR exercise is more pleasant and less uncomfortable, we recommend its use over continuous BFR exercise.

• Keywords: blood flow restriction, isometric strength training, electromiography, rate of percived exertion