Eddie Vedder
2008-02-16, 10:29
En undersökning där man delat upp personer i två grupper, låtit dessa träna lika mycket men med skillnaden att grupp 1 gjorde det i fastande tillstånd och grupp 2 tränade 90 minuter efter en kolhydratrik frukost.
I övrigt såg kosten likadan ut för båda grupperna och totalt sett åt alla försökspersoner lika mycket med samma makrofördelning (kan ju inte utlovas till 100% för varje deltagare givetvis men så var i alla fall upplägget)
Man såg inga ändringar i fettoxidation och inte heller prestation. En faktor som nämns till varför det eventuellt inte påverkade F-gruppens anpassning till mer fettförbrännande träning trodde man dock kunde bero på att kostintaget i sin helhet var precis lika kolhydratrikt som CHO-gruppen.
Skeletal muscle gene response to exercise depends on nutritional status during and after exercise, but it's unknown whether muscle adaptations to endurance training are affected by nutritional status during training sessions. Therefore, this study investigated the effect of an endurance training program (6wk, 3d/week, 1-2h, 75% of peak VO2) in moderately active males. They trained in the fasted (F; n=10) or carbohydrate-fed state (CHO; n=10) while receiving a standardized diet (65%En from carbohydrates, 20%En fat, 15%En protein). Before and after the training period, substrate use during a 2h exercise bout was determined. During these experimental sessions, all subjects were in a fed condition and received extra carbohydrates (1g·kg-1 bw·h-1). Peak VO2 (+7%), succinate dehydrogenase activity, GLUT4, and hexokinase II content were similarly increased between F and CHO. Fatty acid binding protein (FABPm) content increased significantly in F (p=.007). Intramyocellular triglyceride content (IMCL) remained unchanged in both groups. After training, pre-exercise glycogen content was higher in CHO (545±19mmol·kg-1 dw; p=.02), but not in F (434±32mmol·kg-1 dw; p=.23). For a given initial glycogen content, F blunted exercise-induced glycogen breakdown when compared with CHO (p=.04). Neither IMCL breakdown (p=.23) nor fat oxidation rates during exercise were altered by training. Thus, short-term training elicits similar adaptations in peak VO2 whether carried out in the fasted or carbohydrate fed state. Although there was a decrease in exercise-induced glycogen breakdown and an increase in proteins involved in fat handling after fasting training, fat oxidation during exercise with carbohydrate intake was not changed.
Effect of training in the fasted state on metabolic responses during exercise with carbohydrate intake. J Appl Physiol (February 14, 2008).
http://jap.physiology.org/cgi/content/abstract/01195.2007v1?papetoc
Tycker själv den var intressant, ger ju tyvärr inte svar på hur fastande träning under längre period kan inverka om man äter en kost med annorlunda makrofördelning.
Men det känns som att det var ytterligare ett litet bevis för att träningen före frukost är överhypad i fettförbränningssyfte.;)
I övrigt såg kosten likadan ut för båda grupperna och totalt sett åt alla försökspersoner lika mycket med samma makrofördelning (kan ju inte utlovas till 100% för varje deltagare givetvis men så var i alla fall upplägget)
Man såg inga ändringar i fettoxidation och inte heller prestation. En faktor som nämns till varför det eventuellt inte påverkade F-gruppens anpassning till mer fettförbrännande träning trodde man dock kunde bero på att kostintaget i sin helhet var precis lika kolhydratrikt som CHO-gruppen.
Skeletal muscle gene response to exercise depends on nutritional status during and after exercise, but it's unknown whether muscle adaptations to endurance training are affected by nutritional status during training sessions. Therefore, this study investigated the effect of an endurance training program (6wk, 3d/week, 1-2h, 75% of peak VO2) in moderately active males. They trained in the fasted (F; n=10) or carbohydrate-fed state (CHO; n=10) while receiving a standardized diet (65%En from carbohydrates, 20%En fat, 15%En protein). Before and after the training period, substrate use during a 2h exercise bout was determined. During these experimental sessions, all subjects were in a fed condition and received extra carbohydrates (1g·kg-1 bw·h-1). Peak VO2 (+7%), succinate dehydrogenase activity, GLUT4, and hexokinase II content were similarly increased between F and CHO. Fatty acid binding protein (FABPm) content increased significantly in F (p=.007). Intramyocellular triglyceride content (IMCL) remained unchanged in both groups. After training, pre-exercise glycogen content was higher in CHO (545±19mmol·kg-1 dw; p=.02), but not in F (434±32mmol·kg-1 dw; p=.23). For a given initial glycogen content, F blunted exercise-induced glycogen breakdown when compared with CHO (p=.04). Neither IMCL breakdown (p=.23) nor fat oxidation rates during exercise were altered by training. Thus, short-term training elicits similar adaptations in peak VO2 whether carried out in the fasted or carbohydrate fed state. Although there was a decrease in exercise-induced glycogen breakdown and an increase in proteins involved in fat handling after fasting training, fat oxidation during exercise with carbohydrate intake was not changed.
Effect of training in the fasted state on metabolic responses during exercise with carbohydrate intake. J Appl Physiol (February 14, 2008).
http://jap.physiology.org/cgi/content/abstract/01195.2007v1?papetoc
Tycker själv den var intressant, ger ju tyvärr inte svar på hur fastande träning under längre period kan inverka om man äter en kost med annorlunda makrofördelning.
Men det känns som att det var ytterligare ett litet bevis för att träningen före frukost är överhypad i fettförbränningssyfte.;)