[cycomiko]

Originally Posted by Alan Aragon

Yeah, but that's fine for a 30-minute training session involving the legs. I'm wondering what sort of extra demand a training bout with double that volume would impose, given the common practice of training more than one muscle group in a single session, and to what degree that extra demand might raise the ceiling of protein synthesis using a higher dose.

If we compare the effect of EAA with no exercise, and Protien after exercise, the amount to stimulate maximal muscle protein synthesis appears pretty much the same.

But, doing more bodyparts at the same time may influence the tissue uptake of amino acids, which would require a larger dose. But its neither here or there in the bigger picture.

Regardless of that speculation, my main issue here is with the authors' implication of a maximally effective protein dose of 100-120g/day (20g administered 5-6x a day). I'm assuming you're talking about this trial (correct me if I'm wrong):

http://ajpendo.physiology.org/cgi/co...ull/276/4/E628

From the text: "Subjects had not participated in a resistance exercise training program for >1 yr before participating in the study and were instructed not to change their activity patterns for the duration of the study."

Your(sic) wrong



There are three main studies that have looked at dose/response as the main endpoint. The one I was mentioning was the first of htese.

One used IV amino acids
One used Free form amino acids
One used isolated egg protein


Human muscle protein synthesis is modulated by extracellular, not intramuscular amino acid availability: a dose-response study.

Bohé J, Low A, Wolfe RR, Rennie MJ.
Division of Metabolism, Department of Surgery, University of Texas Medical Branch, Shriners Burns Hospital, Galveston, TX 77550, USA.
To test the hypothesis that muscle protein synthesis (MPS) is regulated by the concentration of extracellular amino acids, we investigated the dose-response relationship between the rate of human MPS and the concentrations of blood and intramuscular amino acids. We increased blood mixed amino acid concentrations by up to 240 % above basal levels by infusion of mixed amino acids (Aminosyn 15, 44-261 mg kg-1 h-1) in 21 healthy subjects, (11 men 10 women, aged 29 +/- 2 years) and measured the rate of incorporation of D5-phenylalanine or D3-leucine into muscle protein and blood and intramuscular amino acid concentrations. The relationship between the fold increase in MPS and blood essential amino acid concentration ([EAA], mM) was hyperbolic and fitted the equation MPS = (2.68 x [EAA])/(1.51 + [EAA]) (P < 0.01). The pattern of stimulation of myofibrillar, sarcoplasmic and mitochondrial protein was similar. There was no clear relationship between the rate of MPS and the concentration of intramuscular EAAs; indeed, when MPS was increasing most rapidly, the concentration of intramuscular EAAs was below basal levels. We conclude that the rates of synthesis of all classes of muscle proteins are acutely regulated by the blood [EAA] over their normal diurnal range, but become saturated at high concentrations. We propose that the stimulation of protein synthesis depends on the sensing of the concentration of extracellular, rather than intramuscular EAAs.


Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle.

Cuthbertson D, Smith K, Babraj J, Leese G, Waddell T, Atherton P, Wackerhage H, Taylor PM, Rennie MJ.
Division of Molecular Physiology, School of Life Sciences, University of Dundee, Dundee, Scotland.
The nature of the deficit underlying age-related muscle wasting remains controversial. To test whether it could be due to a poor anabolic response to dietary amino acids, we measured the rates of myofibrillar and sarcoplasmic muscle protein synthesis (MPS) in 44 healthy young and old men, of similar body build, after ingesting different amounts of essential amino acids (EAA). Basal rates of MPS were indistinguishable, but the elderly showed less anabolic sensitivity and responsiveness of MPS to EAA, possibly due to decreased intramuscular expression, and activation (phosphorylation) after EAA, of amino acid sensing/signaling proteins (mammalian target of rapamycin, mTOR; p70 S6 kinase, or p70(S6k); eukaryotic initiation factor [eIF]4BP-1; and eIF2B). The effects were independent of insulin signaling since plasma insulin was clamped at basal values. Associated with the anabolic deficits were marked increases in NFkappaB, the inflammation-associated transcription factor. These results demonstrate first, EAA stimulate MPS independently of increased insulin availability; second, in the elderly, a deficit in MPS in the basal state is unlikely; and third, the decreased sensitivity and responsiveness of MPS to EAA, associated with decrements in the expression and activation of components of anabolic signaling pathways, are probably major contributors to the failure of muscle maintenance in the elderly. Countermeasures to maximize muscle maintenance should target these deficits.

Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men.

Moore DR, Robinson MJ, Fry JL, Tang JE, Glover EI, Wilkinson SB, Prior T, Tarnopolsky MA, Phillips SM.
Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Canada.
BACKGROUND: The anabolic effect of resistance exercise is enhanced by the provision of dietary protein. OBJECTIVES: We aimed to determine the ingested protein dose response of muscle (MPS) and albumin protein synthesis (APS) after resistance exercise. In addition, we measured the phosphorylation of candidate signaling proteins thought to regulate acute changes in MPS. DESIGN: Six healthy young men reported to the laboratory on 5 separate occasions to perform an intense bout of leg-based resistance exercise. After exercise, participants consumed, in a randomized order, drinks containing 0, 5, 10, 20, or 40 g whole egg protein. Protein synthesis and whole-body leucine oxidation were measured over 4 h after exercise by a primed constant infusion of [1-(13)C]leucine. RESULTS: MPS displayed a dose response to dietary protein ingestion and was maximally stimulated at 20 g. The phosphorylation of ribosomal protein S6 kinase (Thr(389)), ribosomal protein S6 (Ser(240/244)), and the epsilon-subunit of eukaryotic initiation factor 2B (Ser(539)) were unaffected by protein ingestion. APS increased in a dose-dependent manner and also reached a plateau at 20 g ingested protein. Leucine oxidation was significantly increased after 20 and 40 g protein were ingested. CONCLUSIONS: Ingestion of 20 g intact protein is sufficient to maximally stimulate MPS and APS after resistance exercise. Phosphorylation of candidate signaling proteins was not enhanced with any dose of protein ingested, which suggested that the stimulation of MPS after resistance exercise may be related to amino acid availability. Finally, dietary protein consumed after exercise in excess of the rate at which it can be incorporated into tissue protein stimulates irreversible oxidation

All three appear to show pretty much the same thing in young people (oldies are in trouble no matter which way you put it), rested or following resistance exercise. ~20-25g of a decent protein to maximise the muscle protein synthesis.

And again, the training protocol was pretty minimal in terms of total work, which was 9 sets for the legs, done in less than 30 minutes.

You would never beable to worship the corpse of Authur Jones with that attitude.

Agreed completely. I'd love to see this type of work carried out long-term using higher-volume training session involving more than a single muscle group. Aaron, serious Q here, what would you like to see in terms of design improvement with this particular line of investigation?

Sirious?

Personally, there is a ton of stuff I would like being measured.

A decent dose/response curve for the effect of carbohydrates on muscle protein balance

A decent combination dose repsonse curve for protein+carbohydrate

Tightly controlled chronic feeding studies, as there is more to protein than just MPS.