Effekten av koffein och kolhydrat vid negativ kaloribalans.

[King Grub]

The ingestion of carbohydrate (+CHO) and caffeine (+CAF) during exercise is a commonly used ergogenic practice. Investigations are typically conducted with subjects who are in a rested state after an overnight fast. However, this state of positive energy balance is not achieved during many work and exercise circumstances. The aim of this study was to evaluate the substrate use and performance effects of caffeine and carbohydrate consumed alone and in combination while participants were in negative energy balance. Male participants (n = 9; 23 ± 3 years; 74.1 ± 10.6 kg) completed 4 trials in random order: –CAF/–CHO, –CAF/+CHO, +CAF/–CHO, and +CAF/+CHO. Diet and exercise were prescribed for 2 days before each trial to ensure negative energy balance. For each trial, before and after 2 h of cycling at 50% of maximal watts, a saliva sample and a muscle biopsy (vastus lateralis) were obtained. A simulated 20 km time trial was then performed. The respiratory exchange ratio was higher (p < 0.05) in +CHO trials and lower (p < 0.05) in the +CAF/+CHO trial than in the –CAF/+CHO trial. Salivary cortisol response was higher (p < 0.05) in the +CAF/–CHO trial than in any of the other trials. Muscle glycogen and heart rates were similar in all trials. Performance in the 20 km time trial was better in the –CAF/+CHO trial than in the –CAF/–CHO trial (p < 0.05), but the +CAF/+CHO trial was no better than the +CAF/–CHO trial (p > 0.05), or any of the other trials. When co-ingested with carbohydrate, caffeine increased fat use and decreased nonmuscle glycogen carbohydrate use over carbohydrate alone when participants are in negative energy balance; however, caffeine had no effect on the 20 km cycling time trial performance.

Appl. Physiol. Nutr. Metab. 33(6): 1079–1085 (2008). Caffeine and carbohydrate supplementation during exercise when in negative energy balance: effects on performance, metabolism, and salivary cortisol.

http://article.pubs.nrc-cnrc.gc.ca/RPAS/RPViewDoc?_handler_=HandleInitialGet&calyLang=eng&journal=apnm&volume=33&articleFile=h08-093.pdf

[forslund]

but the +CAF/+CHO trial was no better than the +CAF/–CHO trial (p > 0.05), or any of the other trials.

Borde inte det här vara grovt påverkat av att testet var så kort? 20 km hinner antagligen de allra flesta under 60 minuter och bevisad effekt av kolhydrater är väl efter 60-90 minuter?

[Scratch89]

Tur att man har valt rätt knark på underskott då. :)

[Eddie Vedder]

Borde inte det här vara grovt påverkat av att testet var så kort?

Jo fast å andra sidan var ju 20-kilometerstestet bara 30 minuter efter 2-timmarscyklingen på 50% av Watt max.

Eller fattade jag den delen fel?

[Scratch89]

Det måste ha varit skönt att cykla efter att ha gjort en muskelbiopsi i låret.

[William]

Det måste ha varit skönt att cykla efter att ha gjort en muskelbiopsi i låret.

Faktiskt inte alls så farligt som det kanske låter.

[Scratch89]

Faktiskt inte alls så farligt som det kanske låter.

You tell me. ;)

[William]

You tell me. ;)

Man är ju bedövad :). Har själv kört både styrketräning och cykling efter biopsitagning vid fyra tillfällen och det var chill.