Author/Editor		Novak, Primož; Vidmar, Gaj; Bajuk, Slavica; Tomšič, Igor; Štefančič, Martin
Title		Moč mišične kontrakcije, izvabljene z električno stimulacijo
Translated title		Strength of muscular contraction elicited with electrical stimulation
Type		članek
Vol. and No.		Letnik 15, št. 3
Publication year		2016
Volume		str. 12-18
ISSN		1580-9315 - Rehabilitacija
Language		slv
Abstract		Izhodišča: Živčno-mišično električno stimulacijo skeletnih mišic pogosto uporabljamo v terapevtske namene. Podatki o izboljšanju mišične moči pri različnih intenzitetah električne stimulacije se v svetovni strokovni literaturi močno razlikujejo. Z naraščanjem intenzitete električna stimulacija postane neprijetna in boleča. Prag bolečine se med posamezniki razlikuje, zato je na pragu bolečine pričakovati različno silo mišične kontrakcije. Cilj naše raziskave je bil ugotoviti, kakšna je moč kontrakcije kvadricepsa, izvabljene z živčno-mišično električno stimulacijo tik pod pragom bolečine (tj. električno stimulacijo maksimalne tolerance), glede na moč, ki jo preiskovanec doseže pri maksimalni voljni izometrični kontrakciji iste mišične skupine. Metode: V raziskavo smo vključili 12 zdravih moških preiskovancev v starosti od 22 do 73 let. Izmerili smo navore pri izometrični kontrakciji ekstenzorjev obeh kolen pri maksimalni voljni kontrakciji in med električno stimulacijo maksimalne tolerance, med katero preiskovanci niso voljno napenjali mišic. Rezultati: Povprečni navor ekstenzorjev kolen, dosežen pri električni stimulaciji maksimalne tolerance, je znašal na desni strani 34,2 Nm oziroma 15 % vrednosti pri maksimalni voljni kontrakciji, in na levi strani v povprečju 39,9 Nm oziroma 18 % vrednosti pri maksimalni voljni kontrakciji. Izrazite povezanosti rezultatov s starostjo nismo opazili pri nobenem od izmerjenih parametrov. Zaključek: Z električno stimulacijo maksimalne tolerance smo izzvali kontrakcijo kvadricepsa s približno 1/6 navora, ki ga preiskovanci dosežejo pri maksimalni voljni izometrični kontrakciji iste mišice. Razlike v odzivnosti so med preiskovanci velike, zato je treba v klinični praksi nastavitev parametrov električne stimulacije prilagoditi posameznemu pacientu.Background: Neuro-muscular electrical stimulation is frequently used for therapeutic purposes. Data on muscle strength improvement using electrical stimulation of different intensities differ widely in the literature. With increasing intensity, stimulation becomes unpleasant and painful. The pain threshold differs between individuals; different muscle force contraction can therefore be expected at pain threshold. The goal of our study was to find out what is the strength of quadriceps contraction, evoked by electrical stimulation bellow the pain threshold (i.e., electrical stimulation of maximal tolerance), compared to the strength achieved at maximal voluntarily isometric contraction of the same muscle group. Methods: Twelve healthy male volunteers, aged 22 to 73, were included in the study. Torques of knee extensors at maximal voluntarily isometric contraction and during electrical stimulation of maximal tolerance without voluntarily contraction was measured for both knees. Results: Average knee extensors torque during electrical stimulation of maximal tolerance was 34.2 Nm (15% of the value of maximal voluntarily isometric contraction) on the right side and 39.9 Nm (18% of value of maximal voluntarily isometric contraction) on the left side. Neither of the parameters exhibited a clear correlation with age. Conclusions: With electrical stimulation of maximal tolerance, quadriceps contraction of approximately 1/6 of the torque achieved at maximal voluntarily isometric contraction of the same muscle was evoked. There were large dBackground: Neuro-muscular electrical stimulation is frequently used for therapeutic purposes. Data on muscle strength improvement using electrical stimulation of different intensities differ widely in the literature. With increasing intensity, stimulation becomes unpleasant and painful. The pain threshold differs between individuals; different muscle force contraction can therefore be expected at pain threshold. The goal of our study was to find out what is the strength of quadriceps contraction, evoked by electrical stimulation bellow the pain threshold (i.e., electrical stimulation of maximal tolerance), compared to the strength achieved at maximal voluntarily isometric contraction of the same muscle group. Methods: Twelve healthy male volunteers, aged 22 to 73, were included in the study. Torques of knee extensors at maximal voluntarily isometric contraction and during electrical stimulation of maximal tolerance without voluntarily contraction was measured for both knees. Results: Average knee extensors torque during electrical stimulation of maximal tolerance was 34.2 Nm (15% of the value of maximal voluntarily isometric contraction) on the right side and 39.9 Nm (18% of value of maximal voluntarily isometric contraction) on the left side. Neither of the parameters exhibited a clear correlation with age. Conclusions: With electrical stimulation of maximal tolerance, quadriceps contraction of approximately 1/6 of the torque achieved at maximal voluntarily isometric contraction of the same muscle was evoked. There were large differences in response betweenifferences in response between participants, therefore electrical stimulation parameters should be adjusted to each patient
Keywords		neuro-muscular electrical stimulation maximal tolerance isokinetic contraction torque živčno-mišična električna stimulacija maksimalne tolerance izometrična kontrakcija navor