This article describes a safe and reliable method to induce and quantify exertional skeletal muscle damage in human subjects.
Sammentrækning-induceret muskelskader via frivillige excentriske (forlængelsesflige) sammentrækninger tilbyder en fremragende model til at studere muskel tilpasning og genopretning i mennesker. Heri diskuterer vi udformningen af en excentrisk øvelse protokol til at fremkalde skader i quadriceps muskler, præget af ændringer i styrke, ømhed, og plasma kreatinkinase niveauer. Denne metode er enkel, etisk, og bredt anvendelig, da den udføres i menneskelige deltagere og eliminerer arterne oversættelse af resultaterne. Fag udføre 300 maksimale excentriske kontraktioner af knæet extensor musklerne med en hastighed på 120 ° / sek på en isokinetisk dynamometer. Omfanget af skaderne er målbar bruge relativt ikke-invasive isokinetiske og isometrisk foranstaltninger af styrke tab, ømhed, og plasma kreatinkinase niveauer over flere dage efter øvelsen. Derfor kan dens anvendelse rettes til bestemte befolkningsgrupper i et forsøg på at identificere mekanismer for muskeltilpasning og regenerering.
The overall goal of this procedure is to induce exertional damage to the quadriceps femoris muscles using voluntary lengthening (eccentric) contractions in human subjects.
Contraction-induced skeletal muscle damage is a common consequence of exercise that is marked by delayed onset muscle soreness1, transient strength loss, and elevated muscle-specific enzymes in the blood2. Exertional muscle damage is most pronounced following exercise to which the subject is unaccustomed, particularly when eccentric contractions are involved3. Exertional muscle damage is typically benign. Soreness subsides, and both serum proteins and strength typically return to pre-damage levels within a few days to weeks after the damaging insult. In extreme cases, exertional muscle damage can lead to a life-threatening syndrome know as rhabdomyolysis. However, exertional muscle damage is usually insufficient to cause clinical rhabdomyolysis in healthy individuals4 in the absence of compounding factors including heat stress, dehydration5, infection6 or rare genetic predispositions7.
Contraction-induced muscle damage is typically less severe than toxin-induced or freezing-induced injury, methods often used in rodent studies8,9. Yet, contraction-induced injury provides a useful method to study the muscle damage response with notable advantages. First, it is a safe and ethical method for use with human subjects1-3. Thus, interspecies translation of the results is not needed as data can be obtained directly from human subjects. Moreover, translating data obtained from rodent studies is very difficult given that the severity of injury seen in the rodent injury models exceeds the level of damage that would be ethical to induce in human subjects. Second, contraction-induced damage is commonly experienced and a natural process of exercise. Therefore, this mode of damage induction is useful for studying muscle damage in the context of exercise, adaptation to exercise as well as overt muscle injury. Here we describe a safe and reliable method to induce and evaluate skeletal muscle damage using lengthening contractions in humans.
Flere trin er afgørende for at opnå de ønskede resultater af denne protokol. For det første skal individer være tilstrækkeligt bekendt til sammentrækning protokoller, især kraftmålinger. Vær sikker på, at emnet forstår præcis, hvad de forventes at gøre, og give dem mulighed for at øve styrkeprøvningerne før dataindsamlingen. Emner der ikke er tilstrækkeligt fortrolig med brug af disse procedurer kan vise en indlæringskurve i dagene efter skaden induktion. Dette kan være en confounding variabel render…
The authors have nothing to disclose.
The authors have no acknowledgements.
Biodex Dynomometer | Biodex Medical Systems | 850-000 | Other models are available and should produce similar results |
Creatine Kinase kit | Sigma-Aldrich | MAK116 | |
Serum Vacutainers | BD Bioscience | 367812 | |
Winged safety push button blood collection set | BD Bioscience | 367338 | |
Cryogenic vials | Sigma-Aldrich | V5007 | We use the 2mL vials to store serum aliquots |