Spændende artikel, JensL. Godt med lidt nye input
Nedenfor har jeg citeret en del af de praktiske implikationer - det er mine fremhævninger.
Distilling the data into firm, specific recommendations is difficult due to the inconsistency of
findings and scarcity of systematic investigations seeking to optimize pre- and/or postexercise
protein dosage and timing. Practical nutrient timing applications for the goal of
muscle hypertrophy inevitably must be tempered with field observations and experience in
order to bridge gaps in the scientific literature. With that said, high-quality protein dosed at
0.4-0.5 g/kg of LBM at both pre- and post-exercise is a simple, relatively fail-safe general
guideline that reflects the current evidence showing a maximal acute anabolic effect of 20-40
g [52,84,85]. For example, someone with 70 kg of LBM would consume roughly 28-35 g
protein in both the pre- and post exercise meal. Exceeding this would be have minimal
detriment if any, whereas significantly under-shooting or neglecting it altogether would not
maximize the anabolic response.
...
Even more so than with protein, carbohydrate dosage and timing relative to resistance
training is a gray area lacking cohesive data to form concrete recommendations. It is tempting
to recommend pre- and post-exercise carbohydrate doses that at least match or exceed the
amounts of protein consumed in these meals. However, carbohydrate availability during and
after exercise is of greater concern for endurance as opposed to strength or hypertrophy goals.
Furthermore, the importance of co-ingesting post-exercise protein and carbohydrate has
recently been challenged by studies examining the early recovery period, particularly when
sufficient protein is provided. Koopman et al [52] found that after full-body resistance
training, adding carbohydrate (0.15, or 0.6 g/kg/hr) to amply dosed casein hydrolysate (0.3
g/kg/hr) did not increase whole body protein balance during a 6-hour post-exercise recovery
period compared to the protein-only treatment. Subsequently, Staples et al [53] reported that
after lower-body resistance exercise (leg extensions), the increase in resting and post-exercise
muscle protein balance from ingesting 25 g whey isolate was not improved by an additional
50 g maltodextrin during a 3-hour recovery period. For the goal of maximizing rates of
muscle gain, these findings support the broader objective of meeting total daily carbohydrate
need instead specifically timing its constituent doses. Collectively, these data indicate an
increased potential for dietary flexibility while maintaining the pursuit of optimal timing.
Jeg har ikke læst hele artiklen endnu. Men
Deres konklusion vedrørende kulhydrat stemmer ikke overens med min praktiske fremgang med at time en meget stor del af mit totale kulhydratindtag i timerne omkring dagens træningspas (hvilket mange andre også gør). Dog skal det siges, at når man normalt ser tale om at gøre dette, så er det for at undgå at have store mængder af insulin i blodet på tidspunkter, hvor det ikke er nødvendigt og hvor man i stedet har et potentiale for at forbrænde fedt. Så vidt jeg kan forstå behandler studiet ikke dette område? De skriver at indtag af carbs i forbindelse med træning
"-...did not increase whole body protein balance during a 6-hour post-exercise recovery
period compared to the protein-only treatment'", En ting er, at det ingen effekt har på den parameter, men derfor kan der vel godt være en ide i at gøre det med tanke på insulin?
Jeg har deltaget i en tidligere debat, hvor noget lignende har været debateret:
http://www.bodybuilding.dk/kulhydrat-efter-traening-t40980.htmlJeg skrev:
Det ser ud til at være vigtigt at din shake ligeledes indeholder kulhydrat. I hvert fald hvis du ikke indtager kulhydrat løbende under træning.
Drikker selv 70-100 gram kulhydrat løbende under min træning alt afhængigt af hvor lang og hård træningen er. Lige efter træning indtager jeg altid minimum 30 gram kulhydrat sammen med mit protein.
Årsagen til dette kan ses i nedenstående studie fra pubmed:
Abstract
Carbohydrate, protein, and carbohydrate-protein supplements were compared to determine their effects on muscle glycogen storage during recovery from prolonged exhaustive exercise. Nine male subjects cycled for 2 h on three separate occasions to deplete their muscle glycogen stores. Immediately and 2 h after each exercise bout, they ingested 112.0 g carbohydrate (CHO), 40.7 g protein (PRO), or 112.0 g carbohydrate and 40.7 g protein (CHO-PRO). Blood samples were drawn before exercise, immediately after exercise, and throughout recovery. Muscle biopsies were taken from the vastus lateralis immediately and 4 h after exercise. During recovery the plasma glucose response of the CHO treatment was significantly greater than that of the CHO-PRO treatment, but the plasma insulin response of the CHO-PRO treatment was significantly greater than that of the CHO treatment. Both the CHO and CHO-PRO treatments produced plasma glucose and insulin responses that were greater than those produced by the PRO treatment (P less than 0.05). The rate of muscle glycogen storage during the CHO-PRO treatment [35.5 +/- 3.3 (SE) mumol.g protein-1.h-1] was significantly faster than during the CHO treatment (25.6 +/- 2.3 mumol.g protein-1.h-1), which was significantly faster than during the PRO treatment (7.6 +/- 1.4 mumol.g protein-1.h-1). The results suggest that postexercise muscle glycogen storage can be enhanced with a carbohydrate-protein supplement as a result of the interaction of carbohydrate and protein on insulin secretion.
(Zawadzki KM, Yaspelkis BB 3rd, Ivy JL. Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise. J Appl Physiol. 1992 May;72(5):1854-9.)
Vigtigheden af protein sammen med kulhydrat og ikke udelukkende kulhydrat dokumenteres samtidig i dette studie, hvis nogen skulle ønske at se dette:
(Ivy JL, Goforth HW Jr, Damon BM, McCauley TR, Parsons EC, Price TB. Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement. J Appl Physiol. 2002 Oct;93(4):1337-44.)
og
Som du selv skriver øger kulhydrat ikke proteinsyntesen, hvorfor du konkludrer at kulhydrat efter træning ikke er nødvendigt. MEN du overser glukose og insulins ekstrem vigtige egenskaber.
Når du indtager kulhydrater nedbrydes disse til glukose i tyndtarmen, og glukosen optages i blodkarrene. Blodets forøgede indhold er glukose fremtvinger produktion og frigivelse af insulin. Insulinen føres ud i blodet og påvirker kroppen celler til at optage glukose, protein og fedt. Glukose lagres som glykogen i musklerne, hvor dine glykogendepoter i forbindelse med den hårde fysiske aktivitet er blevet udtømt. Protein oplagres i musklerne og indgår i proteinsyntesen, som du henviser til.
Det er altså i forbindelse med frigivelsen af insulin at kulhydrater bliver utroligt vigtige. Insulin er meget vigtigt i forbindelse med jagten på større muskler, det er derfor at mange bodybuildere benytter sig af store mængder exogent insulin.
Undskyld den meget lange post

For at opsummere lidt på mit "spørgsmål".
Et timet indtag af kulhydrat lige omkring træning har ikke nogen effekt (jf. studierne) på proteinsyntesen. Men her taget insulin ikke i betragtning. Insulins anabolske evne ved blandt andet at påvirke kroppens celler til at optage glukose, protein og fedt taler vel stadig for at indtage en stor del af sine kulhydrater omkring et træningspas?