Učinek podpražne elektrostimulacije tibialnega živca na navor iztegovalk gležnja zdravih oseb in oseb z multiplo sklerozo

Šinkovec, Lara (author), Spudić, Darjan (mentor), Tomažin, Katja (comentor)

Multipla skleroza (Ms) je bolezen tisočerih obrazov. Njeni simptomi se odražajo z zmanjšanjem aerobne kapacitete, nezmožnostjo aktivacije in atrofijo mišic, kar zmanjša vzdržljivost in moč bolnikov. Elektrostimulacija mišic (ES) je uporabna pri bolnikih z nevro-mišičnimi obolenji, saj vpliva na izboljšanje mišične moči, zakasni pojavljanje mišične atrofije in lajša bolečine zaradi spastičnosti. Podpražna električna stimulacija (PES) predstavlja stimuliranje perifernih senzornih vlaken z uporabo majhnih električnih tokov. PES poveča vzdražnost sklada alfa motonevronov, povzroči rekrutacijo dodatnih ME in zato predstavlja potencialno pozitiven dodatek k vadbi s hotenimi mišičnimi naprezanji pri osebah, ki so gibalno ovirane. Glavni namen raziskave je bil ugotoviti, ali PES spremeni navor iztegovalk gležnja med hotenim izometričnim naprezanjem pri zdravih odraslih osebah in odraslih osebah z Ms. Učinkovitost PES smo preverjali pri različnih intenzivnostih (20, 60 in 100 % največjega hotenega izometričnega naprezanja – NHIN) in z 20 Hz ter 80 Hz vrinjenim vlakom PES. Navor smo izmerili na izometrični gleženjski opornici. V raziskavi je prostovoljno sodelovalo 24 zdravih oseb in 24 oseb z Ms. S tristansko analizo variance smo preverili razlike v navoru a) eno sekundo pred, eno sekundo med in eno sekundo po PES, b) med 20 in 80 Hz protokoloma PES ter c) med skupinama. Z rezultati smo ugotovili statistično značilne razlike med skupinama v vrednostih navora. Po pričakovanjih so bili preizkušanci v skupini Ms šibkejši. Ugotovili smo statistično značilne razlike v vrednostih navora pred, med in po vrinjenem vlaku PES, ne glede na frekvenco PES (20 ali 80 Hz) in intenzivnost NHIN (20, 60 in 100 %). Navor je bil presenetljivo najnižji v intervalu po vrinjenem vlaku PES. Na spremembo navora frekvenca PES ni imela učinka. Rezultati naše raziskave kažejo, da uporabljena protokola PES tibialnega živca v naši raziskavi nista bila učinkovita za akutno povečanje navora iztegovalk gležnja. Ker je bila naša študija prva, v kateri so bila preverjana teoretična izhodišča za povečanje zavestno proizvedene sile ob dodatku PES pri gibalno oviranih osebah, so v prihodnje potrebne dodatne raziskave za potrditev naših rezultatov.

• Language: Slovenian
• Keywords: podpražna elektrostimulacija, multipla skleroza, navor, hotena aktivacija mišic
• Work type: Master's thesis/paper
• Organization: FŠ - Faculty of Sport
• Year: 2024
• Publication date in RUL: 27.09.2024

Secondary language

• Language: English
• Title: Influence of subthreshold electrostimulation of tibial nerve of ankle extensors in healthy subjects and in those with multiple sclerosis

Abstract

Multiple sclerosis (Ms) is a disease of thousand faces. It leaves an impact on aerobic capacity, muscle strength and muscle mass. It causes muscle atrophy which eventually leads to incapability to activate muscles. Electrical stimulation (ES) is recommended for those with neuromuscular diseases because it can increase muscle strength, it delays the onset of muscle atrophy and relieves pain due to spasticity. Subthreshold electrical stimulation (SES) represents stimulation of peripheral sensory fibres using small electrical currents. SES increases the excitability of alpha motoneurons, consequently recruiting additional MEs and thus represents a potentially positive addition to exercise with conscious muscle contraction. The aim of our study was to examine the effect of SES on ankle plantar flexion voluntary isometric contraction torque in healthy subjects and subjects with Ms. The influence of SES was measured during different intensities (20, 60 and 100 % maximal voluntary contraction – MVC) and with 20 Hz or 80 Hz electrical train impulses. We measured the torque using isometric ankle dynamometer device. Twenty-four healthy subjects and subjects with Ms were recruited. We checked the differences in torque between conditions and both groups with the three-way analysis of variance one second before, one second during and one second after the stimulation. The results from our study present statistically significant differences between groups in torque values. As expected, the subjects in Ms group produced lower torque. We also found statistically significant differences in torque values before, during and after SES, regardless of frequency (20 or 80 Hz) and intensity of MVC (20, 60 and 100 %). Torque was the lowest in the interval after SES. The SES frequency had no effect on torque values. The results of our research show that the SES protocols used in our research were not efficient for acute increase in plantar flexion torque production. Since our study was the first testing the theoretical background of the acute increasement of voluntary muscle force production with interpolation of SES among physically disabled people, additional research is needed in the future to confirm our results.

• Keywords: subthreshold electrical stimulation, multiple sclerosis, torque, voluntary muscle activation