Avtor/Urednik		Ušaj, A; Strojnik, V; Jarh, O; Demšar, F
Naslov		Učinek pet tedenske vadbe na mišični pH pri naporu je različen, če uporabimo izometrična ali dinamična krčenja
Prevedeni naslov		Muscle pH at exercise was differently affected by five weeks of training using isometric or dynamic contractions
Tip		članek
Vir		Farm Vestn
Vol. in št.		Letnik 47, št. 3
Leto izdaje		1996
Obseg		str. 303-9
Jezik		slo
Abstrakt		Five subjects trained m. adductor pollicis using two types of contractions: isometric and dynamic. The aim of the tudy was to ascertain of the differences that might occur in muscle pH at standard exercise, using a 31P Magnetic esonance spectroscopy (31P MRS). Training in the first period of 5 weeks was consisted of a sequence of 4x5 min f isometric contractions, performed once per day, 6 times per week. The second training period of 5 weeks started fter 2 weeks of rest. It consisted of dynamic contractions of the same intensity and duration. In the beginning and the end of each period, tests were performed. Each consisted of increasing load of isometric contractions on special platform that was also a housing of MR coil. The contractions intensity grew using an additional load which increased from the 0 to 6 kg. The tests were performed in the bore of the MR magnet (Oxford, England). Reasurements of 31P spectra and calculations of changes of cytosolic pH were made. The effect of the first training period was significant (P less th.0.05) increase of cytosolic pH at the load of 4 kg, from 6.54+-0.21 to 0.94+-0.14, and above that level, respectively. The 14 days rest between both periods had no affested significantly on pH values. Nevertheless, slight decrease of pH to 6.76+-0.16 at load of 4 kg was observed. Second training period of 5 weeks significantly (P less th.0.05) decreased cytosolic pH to 6.43+-0.30 at load of 4kg. Values reached the level similar as before the start of experiment. Results showed that selected intensity and training volume caused positive effect regarding to cytosolic pH when isometric contractions were applied. It seems that the same training characteristics represented non adequate training stimulus if dynamic contractions were used.
Izvleček		Pet preiskovalcev je v dveh, pet tedenskih vadbenih obdobjih uporabilo dva tipa mišičnega krčenja: izometrično in dinamično. Namen poskusa je bil odkriti morebiten diferenciran učinek na mišični pH pri standardnem testnem protokolu. Tvorilo ga je 5-6 izometričnih krčenj m.adductor pollicis v trajanju po 2 minuti. Obremenitev, ki jo je mišia premagovala, se je povečala pri vsakem krčenju, s pomočjo dodatnega bremena za 1 kg in sicer od 0 do 6 kg. Za merjenje mišičnega pH je bila uporabljena fosforna magnetna resonančna sektroskopija (31P MRS). Testni protokol se je izvajal v odprtini MR magneta (Oxford Research, England) tako, da je bila roka pritrjena na ohišje tuljave in uglaševalnih kondenzatorjev. Samo palec je bil gibljiv. Nanj je bilo vpeto breme s pomočjo vrvice. Prvo, pet tedensko vadbeno obdobje, je tvorila vadba, ki jo je vsak preiskovanec opravil 6 krat tedensko. Vsakokrat so opravljena 4 izometrična krčenja po 5 min pri obremenitvi, ki je predstavljala 30% bremena pri največjem izometričnem krčenju. Njen učinek je izraženo povečanje pH pri obremenitvi 4 kg, z začetne vrednosti 6.54+-0.21 na 6.94+-0.14 (P manj kot 0.05). V 14 dnevnem odmoru, ki je sledil, se mišični pH ni spremenil značilno. V drugem vadbenem obdobju, v katerem je uporabljeno dinamično krčenje s frekvenco 1 krčenje na vsaki 2 sek, sicer pa je bilo enako tistemu v prvem obdobju, se je pozitivni učinek vadbe iz prvega obdobja izničil. Mišični pH se je pri 4 kg zmanjšal iz 6.76+-0.16 na 6.43+-0.3 (P manj kot 0.05), to je na nivo, podoben tistemu, ob začetku eksperimenta. Zgleda, da dinamično krčenje, v primerjavi z izometričnim in pri enakih vadbenih pogojih predstavlja manjši vadbeni dražljaj, v našem primeru celo premajhen, da bi povzročil ali celo ohranil pozitivne učinke predhodne vadbe.
Deskriptorji		MUSCLES EXERCISE HAND ADULT ISOMETRIC CONTRACTION NUCLEAR MAGNETIC RESONANCE HYDROGEN-ION CONCENTRATION