Sodium citrate ingestion and muscle performance in acute hypobaric hypoxia
Deutscher übersetzter Titel: | Natriumzitrateinnahme und Muskelleistung unter akuter hypobarer Hypoxie |
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Autor: | Hauswirth, C.; Bigard, A.X.; Lepers, R.; Berthelot, M.; Guezennec, C.Y. |
Erschienen in: | European journal of applied physiology |
Veröffentlicht: | 71 (1995), 4, S. 362-368, Lit. |
Format: | Literatur (SPOLIT) |
Publikationstyp: | Zeitschriftenartikel |
Medienart: | Gedruckte Ressource Elektronische Ressource (online) |
Sprache: | Englisch |
ISSN: | 1439-6319, 0301-5548 |
DOI: | 10.1007/BF00240418 |
Schlagworte: | |
Online Zugang: | |
Erfassungsnummer: | PU199510103347 |
Quelle: | BISp |
Abstract des Autors
Eight subjects were studied on four occasions following ingestion of a 300-ml solution containing either sodium citrate (C, 0.4 g/kg body mass) or placebo (P, sodium chloride 0.045 g/kg body mass), at local barometric pressure (N, PB approximately 740 mmHg, 98,7 kPa) or hypobaric hypoxia (HH, PB = 463 mmHg, 61.7 kPa). At 2 h after ingestion of the solution, the subjects performed prolonged isometric knee-extension at 35% of the maximal voluntary contraction (MVC) measured either in N or HH. Results showed that ingestion of C led to an improvement in muscle endurance. However, this increase in endurance time for knee extensor muscles was only significant in N (+22%, P<0.05, compared to +15%, NS, at N and HH, respectively). Following ingestion of sodium citrate, pre-exercise bicarbonate concentrations and pH levels were significantly higher than those measured after P ingestion. A significant treatment effect was observed for blood lactate concentrations with values higher for C than for P after 4, 6 and 10 min of recovery. Electromyographic signals (EMG) were obtained from the vastus lateralis muscle during the prolonged isometric contraction at 35% MVC. The mean power frequency (MPF) significantly decreased in time under both N-P and N-C conditions. In HH, no significant decrease in MPF was observed with time. The results suggest that C ingestion was an ergogenic aid enhancing endurance during a sustained isometric contraction. In addition, it is suggested that fatigue during prolonged isometric contraction in HH was not directly related to factors determining the EMG signs of fatigue. Verf.-Referat