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Titolo:
METABOLIC AND MYOELECTRICAL EFFECTS OF ACUTE HYPOXEMIA DURING ISOMETRIC CONTRACTION OF FOREARM MUSCLES IN HUMANS - A COMBINED P-31 MAGNETIC-RESONANCE SPECTROSCOPY SURFACE ELECTROMYOGRAM (MRS-SEMG) STUDY
Autore:
BENDAHAN D; BADIER M; JAMMES Y; CONFORTGOUNY S; SALVAN AM; GUILLOT C; COZZONE PJ;
Indirizzi:
FAC MED MARSEILLE,UMR CNRS 6612,CTR RESONANCE MAGNET BIOL & MED,27 BDJEAN MOULIN F-13005 MARSEILLE FRANCE FAC MED MARSEILLE,UMR CNRS 6612,CTR RESONANCE MAGNET BIOL & MED F-13005 MARSEILLE FRANCE FAC MED NORD,URA CNRS 1630,UNITE PHYSIOPATHOL RESP INTEGREE & CELLULAIRE F-13916 MARSEILLE 20 FRANCE
Titolo Testata:
Clinical science
fascicolo: 3, volume: 94, anno: 1998,
pagine: 279 - 286
SICI:
0143-5221(1998)94:3<279:MAMEOA>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
EMG POWER SPECTRUM; CONDUCTION-VELOCITY; STATIC CONTRACTION; MUSCULAR-CONTRACTION; EXERCISING MUSCLE; INTRACELLULAR PH; SKELETAL-MUSCLES; ATP TURNOVER; ARM EXERCISE; FATIGUE;
Keywords:
HYPOXEMIA; P-31 MAGNETIC RESONANCE SPECTROSCOPY; METABOLISM; MUSCLE FATIGUE; SURFACE ELECTROMYOGRAM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
D. Bendahan et al., "METABOLIC AND MYOELECTRICAL EFFECTS OF ACUTE HYPOXEMIA DURING ISOMETRIC CONTRACTION OF FOREARM MUSCLES IN HUMANS - A COMBINED P-31 MAGNETIC-RESONANCE SPECTROSCOPY SURFACE ELECTROMYOGRAM (MRS-SEMG) STUDY", Clinical science, 94(3), 1998, pp. 279-286

Abstract

1, Failure of muscle force during sustained fatiguing contraction is associated with myoelectrical and metabolic alterations, However, the inter-relationships between these two types of events remain unclear, The purpose of this study was to examine the effects of decreased oxygen availability during sustained contraction on myoelectrical and metabolic changes, thereby addressing the issue of fatigue, 2, P-31-Magnetic resonance spectra and surface electromyograms were simultaneously recorded in six subjects (three women and three men) performing isometric contraction of forearm flexor muscles sustained at 60% maximum value of force under aerobic or acute hypoxaemic conditions (inhalation ofa gas mixture containing 12% O-2), 3, The 5 min hypoxaemic rest preceding contraction did not affect the phosphocreatine level and pH value, Under both conditions of oxygen availability, the magnitude of metabolic changes remained similar and the duration of contraction was unaffected (similar workload), However, hypoxaemia significantly reduced the rate of changes in integrated surface electromyogram activity measured in the high-frequency band, Correlative analysis of magnetic resonance spectroscopy and surface electromyogram data shows that for a given surface electromyogram change, metabolic variations were always larger under hypoxaemic conditions, 4, These results suggest that hypoxaemia does not alter metabolic changes, i,e, decrease in pH and phosphocreatine during static contraction, The downward shift of the relationships between myoelectrical and metabolic changes under hypoxaemia points to the existence of a better excitation-contraction coupling in acute hypoxaemia compared with normoxia and this is indicative of an adaptative mechanism.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/10/20 alle ore 23:36:13