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Uvod: Vadba proti uporu je učinkovita metoda za povečanje mišične jakosti ali preprečevanje mišične atrofije, vendar so za vidne učinke potrebne visoke intenzitete, ki predstavljajo velike mehanske obremenitve tkiv in povečujejo tveganje poškodb. Ishemična vadba proti majhnemu uporu se uporablja kot alternativa standardni vadbi proti velikemu uporu, saj velja za relativno varno, hkrati pa naj bi povzročala primerljive ali celo večje spremembe v mišični masi in jakosti. Natančni mehanizmi, odgovorni za spremembe v mišični zmogljivosti, ostajajo neznani. Odprto je tudi vprašanje, v kolikšni meri ishemična vadba proti majhnemu uporu vpliva na hoteno mišično aktivacijo in ali so spremembe dovolj velike, da vplivajo na funkcijo mišic. Namen: Namen diplomskega dela je na podlagi pregleda znanstvene in strokovne literature preučiti vpliv ishemične vadbe proti majhnemu uporu na nivo hotene mišične aktivacije. Metode dela: Iskanje literature je potekalo v podatkovnih zbirkah PubMed, PEDro, Cochrane Library in Science Direct. V pregled so bile vključene raziskave, ki so bile polno dostopne in so ustrezale vključitvenim kriterijem. Rezultati: V pregled literature je bilo vključenih devet raziskav, objavljenih med letoma 2009 in 2020. V sedmih raziskavah so primerjali učinke ishemične vadbe proti majhnemu uporu in učinke vadbe z normalnim pretokom krvi proti majhnemu uporu, v treh raziskavah pa so v primerjavo vključili tudi učinke vadbe z normalnim pretokom krvi proti velikemu uporu. Dve raziskavi sta primerjali različne stopnje okluzije med ishemično vadbo proti majhnemu uporu. Pri enaki intenziteti in količini vadbe ishemična vadba proti majhnemu uporu statistično značilno izboljša nivo hotene mišične aktivacije, a tudi pospeši utrujanje. V dveh raziskavah so poročali, da večje stopnje okluzije izzovejo večje spremembe v hoteni mišični aktivaciji. Razprava in zaključek: Ishemična vadba proti majhnemu uporu lahko izboljša hoteno mišično aktivacijo in pospeši ţivčno-mišično utrujanje. Za optimalen učinek vadbe se priporoča vsaj 60-odstotna okluzija mišice. Kljub visoki stopnji mišične utrujenosti med ishemično vadbo učinki izginejo kmalu po reperfuziji, kar kaţe, da je vpliv ishemije na ţivčno-mišično funkcijo močan, a kratkotrajen. Za zanesljivejše zaključke so potrebne nadaljnje raziskave na večjih vzorcih obeh spolov in z uporabo enotnih standardiziranih raziskovalnih metod. Introduction: Resistance training is an effective method for increasing muscle strength and preventing muscle atrophy, but it is often associated with high mechanical stress in tissues and hence increased risk of injuries. Low-load ischemic training is often used as an alternative to standard high-load resistance training, as it is considered safe and can elicit similar, or greater, gains in muscle size and strength. However, the exact mechanisms responsible for changes in muscle performance remain unknown. It is also poorly understood to what extent low-load ischemic exercise affects the level of voluntary muscle activation and subsequent muscle function. Purpose: To review and analyse scientific data on the effects of low-load ischemic resistance exercise on voluntary muscle activation. Methods: Literature was searched in PubMed, PEDro, Cochrane Library and Science Direct databases. We reviewed original research reports that were accessible in full-text and met set inclusion criteria. Results: Nine studies, published between 2009 and 2020, have been reviewed in detail. Seven studies compared the effects of low-load ischemic resistance exercise with the effects of standard low-load resistance exercise, while in three studies the effects were also compared to groups performing standard high-load exercise. Two studies examined the effects of resistance exercise with different levels of muscle blood flow restriction. At the same intensity and amount of exercise, low-load ischemic resistance exercise has been shown to elicit significantly higher levels of voluntary muscle activation, but also augmented muscle fatigue. Two studies reported that higher levels of blood flow restriction elicited greater changes in voluntary muscle activation. Discussion and conclusion: Low-load ischemic resistance exercise has been shown to augment voluntary muscle activation and accelerate neuromuscular fatigue. At least 60% of muscle occlusion must be utilized during exercise to optimize the training effects. Despite high levels of muscle fatigue during low-load ischemic resistance exercise, it is recuperated soon after reperfusion, showing that the effects of limited blood flow on neuromuscular function are intense but short-lasting. For more reliable conclusions in this regard, further research on larger sample sizes of both genders with utilization of more standardised research methodology is needed. |
