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Thread: Pre-Workout Nutrition REVISITED

  1. #26
    Banned bjohnso's Avatar
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    Quote Originally Posted by TopCat View Post
    I suppose getting a non-clear water bottle would be the easier solution though
    Yeah, that's what I'm going to do. I've done that in the past, and no one has bothered me about it.

  2. #27
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    Quote Originally Posted by Slim Schaedle View Post
    Right now I leave plenty of room for my stims to do their job because I started to find that food (even straight dex) will impair their effect.....well, I should say the actual stimulatory effect your can literally feel.
    slim - could you explain that impairment? Could that simply be corrected by varying your stim's moa? For an extreme example, I guess I just don't see how a dex shake pre-w/o would have any effect on your, say, caffeine, if you just snorted the caffeine. Not that I'd wish the feeling of snorted caffeiene on my worst enemy, but you get the idea. Messing around with methods of admin for the stim should be able to negate that issue, no? (hell, just timing it differently could be great, caffeine has a half life of maybe 3 or 4hr iirc, so if you dropped, waited like 20-30m, then went for the dex, wouldn't that have no/negligible impact upon the caffeine?
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  3. #28
    Banned Slim Schaedle's Avatar
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    Quote Originally Posted by jdeity View Post
    slim - could you explain that impairment? Could that simply be corrected by varying your stim's moa? For an extreme example, I guess I just don't see how a dex shake pre-w/o would have any effect on your, say, caffeine, if you just snorted the caffeine. Not that I'd wish the feeling of snorted caffeiene on my worst enemy, but you get the idea. Messing around with methods of admin for the stim should be able to negate that issue, no? (hell, just timing it differently could be great, caffeine has a half life of maybe 3 or 4hr iirc, so if you dropped, waited like 20-30m, then went for the dex, wouldn't that have no/negligible impact upon the caffeine?
    At first, I would pound caff (actually, a product called diesel fuel, by diesel nutrition) on my way from from class, and then drink a shake when I got home before heading to the gym.


    When I discovered NO products (and the fact that taking the dex shake after caff led to a slight crash b/c of obvious reasons), I started doing the shake 1.5 hours prior, with the AAKG 1 hour prior, and then caff 30 minutes prior.

    This always worked great and really allowed me to pump up the dex amount.

    If I am just eating food beforehand, like tonight since I am doing UD2, I really have to make sure I leave enough time between eating and taking the pills, or else I won't feel a thing.

    I started a thread about injecting caffeine a while back, but no one really had much to say. I am still wondering if caffeine anhydrous could be disolved in a few mLs and be delivered intravenously.
    Last edited by Slim Schaedle; 03-25-2008 at 09:05 PM.

  4. #29
    Just watch me ... Built's Avatar
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    My first thought with the impairment was actually related to insulin resistance: ephedrine for example increases insulin resistance.

    Is this what you meant, Slim?

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    Banned Slim Schaedle's Avatar
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    Quote Originally Posted by Built View Post
    My first thought with the impairment was actually related to insulin resistance: ephedrine for example increases insulin resistance.

    Is this what you meant, Slim?
    Not really, lol.


    I really don't have an explanation for it other than as soon as food hits my stomach, my caff buzz goes bye bye.

    Not just carbs either.


    Although that does make sense in light of crashing post workout from post dextrose.
    Last edited by Slim Schaedle; 03-25-2008 at 10:50 PM.

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    This whole pre-wo meal is my issue right now. I have never trained in the mornings until 6 weeks ago. I love it, but I am having such a hard time getting a legitimate meal that will help me train in the AM. I get up at 6:30ish and I am in the gym by usually 7:45ish.

    It just seems wrong to have a dextrose or WM shake first thing in the morning. Followed by a high carb/protein drink for post-wo. Now not saying that I wont do that. But I need the justification.

    Looking at how my body is during the AM though, I have a hard time eating anything until an hour or so of being up. Oatmeal or even a whole wheat bagel w/ peanut butter takes me some time to get down, plus I feel full through the whole meal.

    Soooo think it would be a good idea for me to try a WM post-wo?
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    Quote Originally Posted by Slim Schaedle View Post
    I started a thread about injecting caffeine a while back, but no one really had much to say. I am still wondering if caffeine anhydrous could be disolved in a few mLs and be delivered intravenously.
    You can shoot caffeine, I'd just wanna verify water is the proper solution (almost positive it is but you'd know that part better than me - an annhydrous will dissolve in water rigth? Or annhydrous is no water, so it could dissolve in ethanol/h20 or lipids? Meh I'm sure you'd be able to find a suitable solution). Oral bioavailability seems close to 100% anyways so your dosages would be about the same too (http://www.springerlink.com/content/g4204112562h13k6/).

    Everything said there is me making my best assumptions lol, please nobody go shooting caffeine based on anything I wrote here lol!! Slim if you want I know someone who I *think* could explain exacts on that, filters/solutions/etc, pm me if you want me to.
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    I'm a lil confused slim - you're separating the pills from the food, but unless I'm just completely misreading what you wrote (possible, been some crazy past days what with my ID theft experience!), it seems you're going food then caffeine pills. Have you messed with the pure anhydrous powders? I use those and they come up REALLY fast, and if it's near food in your stomach, no doubt that some powder dissolved in a couple ounces of gatorade will have like, what, a million times the surface area to digest? The powder's good stuff, essentially free it's so cheap, just a pita to measure and disgusting to drink!
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  9. #34
    Banned bjohnso's Avatar
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    Quote Originally Posted by jdeity View Post
    Have you messed with the pure anhydrous powders? I use those and they come up REALLY fast, and if it's near food in your stomach, no doubt that some powder dissolved in a couple ounces of gatorade will have like, what, a million times the surface area to digest?
    Wut?

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    he's taking pills that need to break down, and has issues because they're not hitting fast enough and he has to time his food around it to make it work. I'm suggesting a pure caffeine powder dissolved in liquid. A caffeine powder dose is scary small, 200mg is a *quarter* of a *quarter* teaspoon, so if he were to do it as I do and dissolve a caffeine powder into gatorade, it'd digest much faster if food is in the equation when compared to simply eating a couple pressed caffeine tablets - the surface are of caffeine in a liquid makes it far more competitive with the food. (and snorting or injecting the powder would bypass the digestive tract and negate the issue completely - but only the most professional of folks can shoot caffeine w/o looking bat-**** crazy lol)
    (kinda like how hard liquor shots are more effective on an empty stomach, and beers are more effective on a full stomach - because the beer has much more surface area to compete for digestion. I hate using the alcohol example because the body will preferentially digest ethanol as it cannot store ethanol, but the general point still stands, if you have a full stomach and want an orally-administered product to react quicker, you'd want to increase the surface area to a certain degree.)
    Last edited by jdeity; 03-26-2008 at 09:14 AM.
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  11. #36
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    Quote Originally Posted by jdeity View Post
    he's taking pills that need to break down, and has issues because they're not hitting fast enough and he has to time his food around it to make it work. I'm suggesting a pure caffeine powder dissolved in liquid. A caffeine powder dose is scary small, 200mg is a *quarter* of a *quarter* teaspoon, so if he were to do it as I do and dissolve a caffeine powder into gatorade, it'd digest much faster if food is in the equation when compared to simply eating a couple pressed caffeine tablets - the surface are of caffeine in a liquid makes it far more competitive with the food. (and snorting or injecting the powder would bypass the digestive tract and negate the issue completely - but only the most professional of folks can shoot caffeine w/o looking bat-**** crazy lol)
    (kinda like how hard liquor shots are more effective on an empty stomach, and beers are more effective on a full stomach - because the beer has much more surface area to compete for digestion. I hate using the alcohol example because the body will preferentially digest ethanol as it cannot store ethanol, but the general point still stands, if you have a full stomach and want an orally-administered product to react quicker, you'd want to increase the surface area to a certain degree.)
    I use powdered caffeine occasionally, and I have the same problem as Slim - when I take it immediately before or a while after eating, it will have no effect. So are you saying that dissolving caffeine anhydrous in gatorade (or dextrose) will increase it's surface area, thereby making it digest faster? How long does that take (ballpark figure)?

  12. #37
    Senior Member Invain's Avatar
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    I know lots of people around here preach about pre-workout nutrition, but has anybody else tried not doing anything before workouts and not noticed a difference? I know it can vary between people, but I took dextrose right before and during my workouts for a few weeks a while ago and to be completely honest noticed absolutely no difference. Before then, and since then, I eat a big dinner probably 3 or 4 hours before I lift and don't really have anything else between then and my workout.

    I admit I have a very weak stomach and there's no way I could attempt to eat something, such as a protein shake before my workout. I actually wait 3 or 4 hours after my meal to lift for that reason, so my stomach has time to settle down. I've eaten dinner around 5 or 6 and puked while working out at 10 or 11 more than once.
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    Quote Originally Posted by jdeity View Post
    I'm a lil confused slim - you're separating the pills from the food, but unless I'm just completely misreading what you wrote (possible, been some crazy past days what with my ID theft experience!), it seems you're going food then caffeine pills. Have you messed with the pure anhydrous powders? I use those and they come up REALLY fast, and if it's near food in your stomach, no doubt that some powder dissolved in a couple ounces of gatorade will have like, what, a million times the surface area to digest? The powder's good stuff, essentially free it's so cheap, just a pita to measure and disgusting to drink!
    I've used powder, not enteric coated, enteric coated, and just about every other combination you can think of aside from injecting and snorthing.

    I've done food or dex prior, as well as caff then dex.

    I have no problem with the powder, although I know some people who were lazy on the measurements and took almost 2 grams at once.

  14. #39
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    Quote Originally Posted by Beholder View Post
    This whole pre-wo meal is my issue right now. I have never trained in the mornings until 6 weeks ago. I love it, but I am having such a hard time getting a legitimate meal that will help me train in the AM. I get up at 6:30ish and I am in the gym by usually 7:45ish.
    I'm not sure what you mean by "wrong."

    I think what you said is perfect.

    But, that is also because it was my method for many years, especially when I was in the air force and deployed b/c I would have really crazy sleep schedules....if you could call it a schedule.
    Last edited by Slim Schaedle; 03-26-2008 at 10:37 AM.

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    Quote Originally Posted by bjohnso View Post
    I use powdered caffeine occasionally, and I have the same problem as Slim - when I take it immediately before or a while after eating, it will have no effect. So are you saying that dissolving caffeine anhydrous in gatorade (or dextrose) will increase it's surface area, thereby making it digest faster? How long does that take (ballpark figure)?
    Taking almost any solid pill and breaking to powder will make it digest faster, and just dropping it into liquid (juice or water, not milk or anything with stuff like casein protein, fats, fiber, etc, because those'll slow it a lot) accomplishes this well.

    Time for onset, and duration, seem to be very varied with caffeine specifically iirc, but for me maybe 10-15m if I had to guess (that'd just be for when I start feeling it, unsure how long to peak levels or anything but slim may know).
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    Quote Originally Posted by Slim Schaedle View Post
    I've used powder, not enteric coated, enteric coated, and just about every other combination you can think of aside from injecting and snorthing.

    I've done food or dex prior, as well as caff then dex.

    I have no problem with the powder, although I know some people who were lazy on the measurements and took almost 2 grams at once.
    2!!!!!! What!? holy jesus, I would've sworn ld50 on that would be less than a friggin gram!
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    Quote Originally Posted by jdeity View Post
    2!!!!!! What!? holy jesus, I would've sworn ld50 on that would be less than a friggin gram!
    Poison control said there is no established lethal dose.

    Basically, the only amount "eastablished" as lethal is the dose that actually kills the person, haha.

    But yeah, the first time my buddy apparently mistook arginine or citrulline malate for the caffeine and took like a tablespoon.

    Second time, the other guy was just too lax when measuring.

    Come to think of it, I know smeone else who took a ton after they had started drinking.

    That stuff is dangerous, haha.
    Last edited by Slim Schaedle; 03-26-2008 at 03:20 PM.

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    wow! Now I don't feel so bad about my mini-od on it lol!!!

    I think there is an ld50 on that, I'm like 99% sure there is one out there. Can't imagine anyone really cares, but I'm almost positive there is a value. But if you dose properly it's irrelevant anyways haha! I hate it because I only have a 1/4tsp measurement as my lowest, so I have to eye out a 1/4 of that, so when I'm aiming for 200 and get 400, it can really make the day suck!
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  19. #44
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    Quote Originally Posted by jdeity View Post
    wow! Now I don't feel so bad about my mini-od on it lol!!!

    I think there is an ld50 on that, I'm like 99% sure there is one out there. Can't imagine anyone really cares, but I'm almost positive there is a value. But if you dose properly it's irrelevant anyways haha! I hate it because I only have a 1/4tsp measurement as my lowest, so I have to eye out a 1/4 of that, so when I'm aiming for 200 and get 400, it can really make the day suck!
    Tell ya what, when I was using Diesel Fuel (won't post link out of caution) I would open the capsules and carefully transfer some more anhydrous powder into the extra space, and then close the capsule back up.

    Worked great

  20. #45
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    http://www.ncbi.nlm.nih.gov.proxy.li...ubmed_RVDocSum

    J Strength Cond Res. 2003 Feb;17(1):187-96.Links

    Carbohydrate supplementation and resistance training.

    Haff GG, Lehmkuhl MJ, McCoy LB, Stone MH.

    Human Performance Laboratory, Midwestern State University, Wichita Falls, Texas 76308, USA. haffgg@appstate.edu

    There is a growing body of evidence suggesting that the performance of resistance-training exercises can elicit a significant glycogenolytic effect that potentially could result in performance decrements. These decrements may result in less than optimal physiological adaptations to training. Currently some scientific evidence suggests that carbohydrate supplementation prior to and during high-volume resistance training results in the maintenance of muscle glycogen concentration, which potentially could result in the maintenance or increase of performance during a training bout. Some researchers suggest that ingesting carbohydrate supplements prior to and during resistance training may improve resistance-training performance. Additionally, the ingestion of carbohydrates following resistance exercise enhances the resynthesis of muscle glycogen, which may result in a faster time of recovery from resistance training, thus possibly allowing for a greater training volume. On the basis of the current scientific literature, it may be advisable for athletes who are performing high-volume resistance training to ingest carbohydrate supplements before, during, and immediately after resistance training.
    PMID: 12580676 [PubMed - indexed for MEDLINE]

  21. #46
    Banned Slim Schaedle's Avatar
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    The copy/paste got a little messed up in places due to the tables and graphs....which aren't there.


    Timing of amino acid-carbohydrate ingestion alters
    anabolic response of muscle to resistance exercise


    KEVIN D. TIPTON,1,2 BLAKE B. RASMUSSEN,1,2 SHARON L. MILLER,1,2 STEVEN E. WOLF,1
    SHARLA K. OWENS-STOVALL,1 BART E. PETRINI,1 AND ROBERT R. WOLFE1,2

    1Department of Surgery, University of Texas Medical Branch, and 2Metabolism Unit,
    Shriners Hospitals for Children, Galveston, Texas 77550
    Received 5 September 2000; accepted in final form 6 March 2001
    Tipton, Kevin D., Blake B. Rasmussen, Sharon L.
    Miller, Steven E. Wolf, Sharla K. Owens-Stovall, Bart E.
    Petrini, and Robert R. Wolfe.

    Timing of amino acid-carbohydrate
    ingestion alters anabolic response of muscle to
    resistance exercise. Am J Physiol Endocrinol Metab 281:
    E197–E206, 2001.

    —The present study was designedto determine
    whether consumption of an oral essential amino
    acid-carbohydrate supplement (EAC) before exercise results
    in a greater anabolic response than supplementation after
    resistance exercise. Six healthy human subjects participated
    in two trials in random order, PRE (EAC consumed immediately
    before exercise), and POST (EAC consumed immediately
    after exercise). A primed, continuous infusion of L-[ring-
    2H5]phenylalanine, femoral arteriovenous catheterization,
    and muscle biopsies from the vastus lateralis were used to
    determine phenylalanine concentrations, enrichments, and
    net uptake across the leg. Blood and muscle phenylalanine
    concentrations were increased by ;130% after drink consumption
    in both trials. Amino acid delivery to the leg was
    increased during exercise and remained elevated for the 2 h
    after exercise in both trials. Delivery of amino acids (amino
    acid concentration times blood flow) was significantly greater
    in PRE than in POST during the exercise bout and in the 1st
    h after exercise (P , 0.05). Total net phenylalanine uptake
    across the leg was greater (P 5 0.0002) during PRE (209 6 42
    mg) than during POST (81 6 19). Phenylalanine disappearance
    rate, an indicator of muscle protein synthesis from blood
    amino acids, increased after EAC consumption in both trials.
    These results indicate that the response of net muscle protein
    synthesis to consumption of an EAC solution immediately
    before resistance exercise is greater than that when the
    solution is consumed after exercise, primarily because of an
    increase in muscle protein synthesis as a result of increased
    delivery of amino acids to the leg.
    muscle protein synthesis; muscle protein breakdown; stable
    isotopes; supplementation

    BOTH EXERCISE AND NUTRITIONAL SUBSTRATES play important
    roles in muscle protein metabolism. An acute bout
    of resistance exercise increases muscle protein synthesis
    more than breakdown, so that net muscle protein
    balance (synthesis minus breakdown) is increased (5,
    19, 20). Hyperaminoacidemia at rest has similarly
    been demonstrated to increase net synthesis of muscle
    protein, primarily by stimulating muscle protein synthesis
    (1, 6). After intense resistance exercise, increased
    amino acid availability via intravenous infusion
    was shown to increase the rate of muscle protein
    synthesis above levels observed with amino acid infusion
    at rest (6). Thus exercise and amino acids seem to
    have complementary effects on muscle protein synthesis.
    Furthermore, the normal postexercise increase in
    muscle protein breakdown was attenuated when
    amino acids were infused after an exercise bout. Synthesis,
    in this case, exceeded breakdown, resulting in
    net muscle protein synthesis. Subsequently, we demonstrated
    that a solution of amino acids given orally
    was just as effective as intravenous amino acid infusion
    for developing net muscle protein synthesis after
    resistance exercise (27).

    A combination of amino acids, to increase amino acid
    availability, and carbohydrates, to stimulate insulin
    release, should be a potent stimulator of net muscle
    protein synthesis. We recently demonstrated that
    ingestion of a bolus of 6 g of amino acids combined
    with 35 g of carbohydrates at both 1 and 3 h postexercise
    resulted in muscle protein anabolism (21).
    During an exercise bout, there may be a net loss of
    muscle protein, because protein synthesis is either
    decreased (8) or unchanged (9), whereas protein
    breakdown is generally considered to be elevated (22).
    Although muscle protein synthesis is increased after
    exercise, it appears that this response is not stimulated
    until some time after the exercise bout (17). Hyperaminoacidemia
    from ingestion of amino acids during
    the exercise bout, as opposed to after exercise, may
    counter the net loss of muscle protein, thereby creating
    a more favorable situation for muscle growth. The
    purpose of the present study was to determine whether
    ingesting a combination of amino acid and carbohydrate
    before exercise is more effective in stimulating
    net muscle protein synthesis than ingesting the mixture
    after exercise.

    Address for reprint requests and other correspondence: K. D.
    Tipton, Metabolism Unit, Shriners Hospital for Children, 815 Market
    St., Galveston, TX 77550 (E-mail: ktipton@utmb.edu).
    The costs of publication of this article were defrayed in part by the
    payment of page charges. The article must therefore be hereby
    marked ‘‘advertisement’’ in accordance with 18 U.S.C. Section 1734
    solely to indicate this fact.

    Am J Physiol Endocrinol Metab
    281: E197–E206, 2001.
    0193-1849/01 $5.00 Copyright © 2001 the American Physiological Society http://www.ajpendo.org E197
    on March 26, 2008 ajpendo.physiology.org Downloaded from

    METHODS

    Subjects
    Six healthy volunteers (3 females, 3 males) were studied in
    the postabsorptive state. The study design, purpose, and
    possible risks were explained to each subject before written
    consent was obtained. The Institutional Review Board and
    the General Clinical Research Center (GCRC) of the University
    of Texas Medical Branch at Galveston approved the
    study protocol. All subjects were healthy, nondiabetic, and
    normotensive. They had a normal cardiac rhythm with no
    abnormalities, as judged by medical history, physical examination,
    resting electrocardiogram, and laboratory blood and
    urine tests. Subjects were recreationally active and were
    instructed to refrain from physical exercise for $24 h before
    being studied. Mean (6SE) age was 30.2 6 3.1 yr, height was
    1.71 6 0.03 m, weight was 66 6 6 kg, body mass index was
    22 6 1 kg/m2, and leg volume was 9.78 6 0.61 liters. At least
    1 wk before the initial infusion study, each subject was
    familiarized with the leg press and leg extension machine,
    and their one-repetition maximum (1RM, the maximum
    weight that can be lifted for one repetition) was determined
    on each. Mean 1RM for the leg press was 122.9 6 12.8 kg and
    for the leg extension was 92.3 6 13.7 kg.

    Experimental Protocol

    The protocol was designed to determine whether an oral
    amino acid-carbohydrate solution (EAC) would be a more
    effective stimulator of muscle protein anabolism if given
    immediately before or immediately after a resistance exercise
    bout. Each subject participated in two trials in random
    order. The response of muscle protein metabolism was determined
    during and after an intense resistance exercise bout
    while each subject consumed, on separate occasions, a bolus
    of EAC immediately before exercise (PRE) or immediately
    after exercise (POST). Study days were separated by $2 mo.
    Subjects were instructed to maintain a consistent dietary
    intake pattern throughout the duration of the study. One
    female subject completed only the PRE trial; thus all data
    reflect means of six subjects for PRE and five subjects for
    POST. A schematic representation of the study protocol is
    shown in Fig. 1.

    Subjects reported to the GCRC on the evening before each
    study day and began fasting at 2200. After the overnight fast,
    at ;0600, an 18-gauge polyethylene catheter was inserted
    into a large peripheral arm vein for the infusion of stable
    isotopic tracers of amino acids. Catheters were inserted in
    positions to prevent occlusion by bending of the arms. Subjects
    were subsequently transported to the Exercise Metabolism
    Laboratory in the Shriners Hospital for Children,
    Galveston. After background blood samples were taken, a
    primed, continuous infusion of L-[ring-2H5]phenylalanine
    was started at ;0630 and continued throughout the protocol.
    The priming dose was 2 mmol/kg, and the infusion rate was
    0.05 mmolzmin21 zkg21. Catheters were then placed in the
    femoral artery and vein, as well as a second peripheral arm
    vein contralateral to the infusion site. The femoral arterial
    catheter was also used for the continuous infusion of indocyanine
    green (ICG).

    After 2 h of infusion to establish an isotopic steady state,
    resting measurements were made of amino acid concentrations
    and enrichments in the femoral artery and vein, as well
    as muscle. Three blood samples, separated by ;10 min, were
    taken from the femoral artery and vein for the measurement
    of plasma arterial and venous amino acid enrichments and
    concentrations. Blood samples were immediately placed into
    preweighed tubes containing 1 ml of sulfosalicylic acid per
    milliliter of blood and tubes containing lithium heparin. Leg
    blood flow was measured by the dye-dilution technique during
    this time (4). Briefly, ICG (0.5 mg/ml) was infused (60
    ml/h) into the femoral artery. Blood samples were simultaneously
    taken from the femoral vein and a peripheral vein to
    measure ICG concentration. The ICG infusion was briefly
    halted and then quickly resumed to allow sampling from the
    femoral artery for isotopic measurements. Immediately after
    the blood sampling, a percutaneous muscle biopsy was taken
    from the vastus lateralis. Muscle biopsies were taken from
    the lateral portion of the vastus lateralis with sterile technique.
    The skin and subcutaneous tissue were anesthetized,
    and an ;6-mm incision was made in the skin and muscle
    fascia. A 5-mm Bergstro¨m biopsy needle (Depuy, Warsaw,
    IN), with the cutting window closed, was advanced 3–5 cm
    through the fascia deep into the muscle. With suction applied,
    the cutting cylinder was opened and then closed 2–3
    times. A sample of ;50 mg of mixed muscle tissue was
    obtained with each biopsy. Each sample was quickly (within
    1 min) rinsed with ice-cold saline, blotted dry, and frozen in
    liquid N2.

    Immediately after the first muscle biopsy, subjects performed
    an intense leg resistance exercise bout. Before initiation
    of the resistance exercise routine, subjects consumed
    either a 500-ml bolus of the EAC solution (PRE) or a placebo
    solution (POST). The exercise bout consisted of 10 sets of 8
    repetitions of leg press at 80% of 1RM and 8 sets of 8
    repetitions of leg extension at 80% of 1RM. The rest interval
    between sets was ;2 min, and the entire exercise bout was
    completed in ;45–50 min. Blood samples were taken from
    the femoral artery and vein after the 4th and 8th sets of leg
    press (;10 and 20 min from the beginning of the exercise)
    and the 2nd and 8th, or final, sets of leg extension (;30 and
    45 min from the beginning of the exercise). A second muscle
    biopsy was taken in the rest interval between the 7th and 8th
    sets of leg extension. A second bolus drink, placebo for the
    PRE trial and EAC for the POST trial, was consumed immediately
    after exercise and the final blood draw. A series of
    arterial and venous blood samples and two muscle biopsies
    were taken in the 2 h after exercise. Blood samples were
    drawn at 10, 20, 30, 45, 60, 90, and 120 min after exercise.
    Fig. 1. Schematic representation of the study protocol. Time values
    are in minutes from the end of exercise. AV, arteriovenous; EX,
    exercise; EAC, essential amino acid-carbohydrate (supplement); ring
    d5-Phe, L-[ring-2H5]phenylalanine.
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    Muscle biopsies were taken at ;55 and 115 min after exercise
    and the ingestion of the 2nd bolus drink.
    EAC Solution

    Each subject consumed two 500-ml bolus drinks during
    each trial. The order of the trials was randomly selected.
    During the PRE trial, the EAC drink was consumed immediately
    before initiation of the exercise bout, and the placebo
    was consumed immediately upon cessation of the exercise
    bout. For the POST trial, the order was reversed. The EAC
    consisted of 6 g of essential amino acids, in amounts designed
    to increase muscle free intracellular amino acid levels in
    proportion to their respective requirements for protein synthesis,
    and 35 g of sucrose in 500 ml of deionized-distilled
    water. The amounts of essential amino acids in a 500-ml
    bolus EAC solution were (mg and mmol, respectively) histidine
    0.65, 4.2; isoleucine 0.60, 4.6; leucine 1.12, 8.5; lysine
    0.93, 6.4; methionine 0.19, 1.3; phenylalanine 0.93, 5.6; threonine
    0.88, 7.4; and valine 0.7, 6.0. Additionally, 0.0605 g of
    L-[ring-2H5]phenylalanine was added to the solution to maintain
    isotopic steady state. A small amount of artificial sweetener,
    containing aspartame, was added to the EAC to improve
    palatability. The placebo solution was composed of
    deionized-distilled water and an artificial sweetener containing
    aspartame. The placebo contained ,200 mg of phenylalanine.

    Analysis of Samples

    Blood. Amino acid enrichment and concentration of phenylalanine
    in whole blood were measured by gas chromatography-
    mass spectrometry (GC-MS; model 5989B, Hewlett-
    Packard, Palo Alto, CA) (18). Upon thawing, 500 ml of the
    sulfosalicylic extract was passed over a cation exchange column
    (Dowex AG 50W-8X, 100–200 mesh H1 form; Bio-Rad
    Laboratories, Richmond, CA) and dried under vacuum using
    a Speed Vac (Savant Instruments, Farmingdale, NY). To
    determine the enrichment of infused amino acids in whole
    blood, the tert-butyldimethylsilyl (t-BDMS) derivative of each
    amino acid was made according to previously described procedures
    (5, 18, 19). Isotopic enrichments were determined by
    GC-MS (model 5989B, Hewlett-Packard) and expressed as a
    tracer-to-tracee ratio (t/T) (16). Concentrations of free amino
    acids were determined using an internal standard solution,
    as previously described (4, 5, 18, 19). The internal standard
    used was L-[ring-13C6]phenylalanine (50 mmol/l) added in a
    ratio of ;100 ml/ml of blood. Because the tube weight was
    known, the amount of blood could also be determined, and
    the blood amino acid concentration was determined from the
    internal standard enrichments measured by GC-MS on the
    basis of the amount of blood and internal standard added (4,
    5, 18, 19). Appropriate corrections were made for overlapping
    spectra that contributed to the t/T (23). Additionally, m15
    enrichments were corrected 6% for contributions from m16.
    Leg blood flow was determined by spectrophotometrically
    measuring the ICG concentration in serum from the femoral
    and the peripheral veins, as described previously (4, 5, 19).
    Leg plasma flow was calculated from steady-state values of
    dye concentration and converted to blood flow by use of the
    hematocrit (4, 5, 18). Plasma insulin levels were determined
    by radioimmunoassay (Diagnostic Products, Los Angeles,
    CA). The intra-assay coefficient of variation (CV) was 1.45%.
    Muscle. Muscle biopsy tissue samples were analyzed for
    mixed protein-bound and free intracellular amino acid enrichment
    and concentration, as previously described (4, 5, 18,
    19). Tissue biopsies (;50 mg) of the vastus lateralis were
    immediately blotted and frozen in liquid N2. Samples were
    then stored at 280°C until processed. Upon thawing, the
    ;25–30 mg of tissue were weighed and protein precipitated
    with 0.5 ml of 10% perchloric acid. The tissue was then
    homogenized and centrifuged, and the supernatant was collected.
    This procedure was repeated two more times, and the
    pooled supernatant (;1.3 ml) was processed, as were the
    blood samples described above in Blood. To determine intracellular
    enrichment of infused tracers, the t-BDMS derivative
    was prepared as previously described (4, 5, 19) and
    analyzed by GC-MS. Intracellular enrichment was determined
    by correction for extracellular fluid on the basis of the
    chloride method (2). Muscle free amino acid concentration
    was measured with the internal standard method, with corrections
    for the contribution of extracellular fluid and for
    overlapping spectra, as described previously (4, 5, 18, 19).
    The remaining pellet of muscle tissue was further washed,
    twice with 0.9% saline and three times with absolute ethanol.
    It was then placed in an oven and dried at 50°C overnight.
    The dried pellet was then hydrolyzed at 110°C for 24 h with
    6 N HCl. The protein hydrolysate was then passed over a
    cation exchange column and dried by Speed Vac derivatized
    with t-BDMS, as described in Blood. Enrichment of proteinbound
    L-[ring-2H5]phenylalanine was determined by GC-MS
    (model 5973, Hewlett-Packard) with a splitless injection and
    positive electron impact ionization. Mass-to-charge ratios
    (m/z) 338 and 341 were monitored. These ions are the m13
    and m15 enrichments, respectively, where m10 is the lowest
    molecular weight of the ion. The ratio of m15/m13 was used
    because it is more sensitive than the traditional m15/m10
    (used for blood samples). Enrichment from the protein-bound
    samples was determined with a linear standard curve of
    known m15/m13 ratios and corrected back to the absolute
    change in m15 enrichment over the incorporation period.

    Calculations

    Chemical net amino acid balance (NB) across the leg was
    calculated from the difference between the femoral arterial
    and venous concentrations multiplied by the blood flow. Thus
    NB 5 ~Ca 2 Cv! z BF
    where Ca is arterial amino acid concentration, Cv is venous
    amino acid concentration, and BF is leg blood flow.
    Area under the curve was used to calculate total, as well as
    essential and nonessential, amino acid uptake (mg) across
    the leg for a given time period. The resting value was used as
    baseline, so that all values reflected the uptake due to ingestion
    of EAC. The amount of phenylalanine that was taken up
    by the leg and utilized for protein synthesis was calculated by
    Cm4 2 Cm1 5 Cm42m1
    where Cm4 and Cm1 are the phenylalanine concentrations in
    the intracellular pool of the final (4th) and initial (1st) muscle
    biopsy. Cm4-m1 is the amount of phenylalanine remaining in
    the muscle at the end of the study.
    Cm42m1 z LV z 0.6 5 total Phe
    where total Phe is the total amount of phenylalanine remaining
    in the leg at the end of the study, LV is leg volume, and
    0.6 is the volume of leg that is muscle (10).
    uptake 2 total Phe 5 Phe for MPS
    where uptake is uptake of phenylalanine across the leg, and
    Phe for MPS is the amount of phenylalanine taken up by the
    leg and utilized for muscle protein synthesis.
    Because phenylalanine is not metabolized in muscle, muscle
    protein synthesis and breakdown can be estimated using
    the NB across the leg and the arterial and venous enrichments
    of L-[ring-2H5]phenylalanine blood (26, 29). The rate of
    appearance (Ra) and rate of disappearance (Rd) of L-[ring-
    2H5]phenylalanine were calculated as estimations of muscle
    protein breakdown and muscle protein synthesis, respectively,
    from plasma amino acids in the blood (25, 29)
    Ra 5 ~Ea/Ev 2 1! z Ca z BF
    where Ea is arterial enrichment of L-[ring-2H5]phenylalanine,
    Ev is venous enrichment, and Rd is NB 1 Ra.
    Ra, Rd, and NB were calculated for four time periods by
    combining the individual measurements within each period
    and using the mean values in the calculations.

    Data Presentation and Statistical Analysis

    Data are presented as means 6 SE. Results across time for
    phenylalanine concentration were compared by one-way
    ANOVA, with significance set at P , 0.05. When the overall
    P , 0.05, Dunnett’s post hoc test was used to detect individual
    differences between rest and each time point. Differences
    between PRE and POST for each time period and for total
    phenylalanine uptake were detected with Student’s t-test
    with unpooled variances, with significance set at P , 0.05.
    Leg blood flow, phenylalanine enrichment, Ra, Rd, NB,
    delivery to the leg, and muscle concentration are presented
    as means of four periods: Rest, Exercise, Hour 1 Postexercise,
    and Hour 2 Postexercise. The model used to determine statistical
    differences for each of these variables (except for
    muscle concentration) is of the form
    Ys,Tr,t 5 Ss 1(
    j 5 1
    3
    ATr,tt j 1 error
    where s is 1,2,. . .,6 (Ss is the effect of subject s), Tr is 0,1 (Tr
    is the treatment, 0 is PRE, 1 is POST), t (the time period) is
    1, 2, 3, or 4.
    For muscle concentration, the model (which requires deletion
    of the one subject who did not participate in the POST
    part of the study) is
    Ys,Tr,t 5 Ss,Tr 1(
    j 5 1
    3
    ATr,tt j 1 error
    This change was made because of the apparently large
    change in baseline between PRE and POST studies for some
    of the subjects. The object of the analysis is to determine in
    which, if any, time periods (t 5 1, 2, 3, or 4) the conditions
    (
    j 5 1
    3
    A0,tt j Ţ(
    j 5 1
    3
    A1,tt j
    are satisfied, and for
    Tr 5 0, 1 and t
    which of the following hold
    (
    j 5 1
    3
    ATr,tt j Ţ(
    j 5 1
    3
    ATr,tt j
    and in those cases to obtain some idea of the magnitudes of
    the change from the first to the second term. A general linear
    model program was run with the measured data to address
    these questions.

    RESULTS

    Blood Phenylalanine Concentrations
    and Enrichments
    Ingestion of EAC resulted in significant hyperaminoacidemia
    in both the PRE and POST trials (Fig. 2).
    Mean phenylalanine concentration increased by ;67%
    in the first 10 min of exercise and was significantly
    increased over resting levels by 10 min after exercise
    during the PRE trial. Phenylalanine concentration increased
    further after cessation of exercise and peaked
    ;30 min postexercise at levels ;135% above basal.
    Phenylalanine concentration declined from 30 min postexercise
    until 120 min postexercise. During POST,
    mean phenylalanine concentration was unchanged
    during exercise, increased significantly at 20 min postexercise,
    peaked at ;130% of resting values 30 min
    postexercise, and then declined steadily until 120 min
    postexercise.

    Mean enrichments of L-[ring-2H5]phenylalanine are
    presented as means of the four time periods in Table 1.
    Arterial enrichment was decreased from rest during
    exercise in both trials and in the 2nd h postexercise in
    POST. Arteriovenous difference in enrichments was
    decreased during exercise during both trials and during
    the 1st h after exercise during PRE.
    Fig. 2. Arterial and venous phenylalanine concentrations over time
    for PRE trial (EAC before exercise, top) and POST trial (EAC after
    exercise, bottom). *Significantly different from resting levels (time
    255), P , 0.05.
    E200

    Muscle Phenylalanine Concentrations

    Muscle intracellular free phenylalanine concentrations
    are summarized in Fig. 3. Phenylalanine concentrations
    in muscle were significantly greater at rest
    during the PRE trial than during POST. During PRE,
    muscle phenylalanine concentration was increased
    46% by the end of exercise and was further increased to
    86% above basal levels 1 h after exercise. Two hours
    after exercise, and thus 3 h after ingestion of EAC,
    muscle phenylalanine concentrations were 65% above
    basal. During POST, muscle phenylalanine concentrations
    were not increased during exercise but were significantly
    elevated above rest and exercise levels at 2 h
    postexercise, i.e., 2 h after ingestion of EAC, respectively.
    When the differences in resting values are accounted
    for, muscle phenylalanine concentration was
    not significantly different between PRE and POST at
    any time point.

    Blood Flow and Phenylalanine Delivery to the Muscle

    Blood flow to the leg at rest was not different between
    treatments (Table 2). Resistance exercise significantly
    increased leg blood flow by ;324% during PRE
    and by ;201% during POST. In the 1st h after exercise,
    leg blood flow was still significantly elevated
    above rest during both trials, but there was no difference
    from rest during the 2nd h. During exercise and in
    the 1st h after exercise, leg blood flow was significantly
    greater for PRE than for POST.

    Amino acid delivery to the leg (Ca 3 BF) at rest was
    not significantly different between trials (Table 2).
    During exercise, delivery was increased by ;650% in
    the PRE trial and by almost 250% in the POST trial.
    Delivery remained elevated above resting levels during
    the 1st h after exercise for both trials but was not
    increased in the 2nd h postexercise. Phenylalanine
    delivery to the muscle was greater in PRE than POST
    during exercise and the 1st h after exercise.

    Plasma Insulin

    Arterial insulin values for each time period are
    shown in Table 3. Insulin levels significantly increased
    after EAC consumption in each trial, i.e., during exercise
    for PRE and immediately after exercise for POST.
    Insulin remained elevated during the 1st h postexercise
    in PRE and returned to resting levels by the 2nd h
    postexercise in both trials.

    Phenylalanine Uptake Across the Leg
    Figure 4 shows the net phenylalanine uptake across
    the leg measured over 3 h for the PRE and POST trials.
    Net uptake of phenylalanine was ;160% greater in
    PRE than in POST during the entire 3 h. The percentage
    of ingested phenylalanine that was taken up by the
    leg was almost threefold greater (P 5 0.01) during PRE
    (21 6 4%) than during POST (8 6 2%), or 42 6 8 vs.
    16 6 4% for PRE vs. POST, respectively, for both legs.
    More phenylalanine remained in the muscle intracellular
    pool of the leg at the end of the study in POST
    than in PRE (P 5 0.04; 24 6 3 and 42 6 8 for PRE and
    POST, respectively). Thus, over the 3 h of the study,
    180 6 50 mg of phenylalanine were taken up and
    incorporated into protein during PRE and 39 6 18 mg
    during POST (P 5 0.02).

    When these values are calculated for only the final
    2 h of each trial, the differences narrow from the full
    3 h and do not reach statistical significance, but the
    trend for PRE values to be greater than POST remains.
    Phenylalanine uptake for only the 2 h postexercise was
    243 6 120 mg phenylalanine for PRE and 130 6 45 mg
    phenylalanine for POST (P 5 0.19). The mean percentage
    of ingested phenylalanine taken up by one leg in
    the final 2 h postexercise only was 80% greater during
    PRE (25 6 12%) than during POST (13 6 5%; P 5
    Table 1. Mean arterial and venous phenylalanine enrichments and arteriovenous difference in enrichments
    in PRE and POST trials

    Rest Exercise 1 H Post-Ex 2 H Post-Ex
    Artery PRE 0.088460.0134 0.072460.0084* 0.069160.0092 0.075960.0126
    POST 0.088660.0165 0.068760.0108* 0.066460.0117 0.069160.121*
    Vein PRE 0.065560.0087 0.068060.0078 0.064160.0079 0.066760.0092
    POST 0.065660.0118 0.064360.0099 0.059860.0106 0.060160.0100
    a-v Difference PRE 0.015160.0072 0.004460.0011* 0.005460.0018* 0.009260.0038
    POST 0.023060.0049 0.004460.0010* 0.006760.0011 0.009060.0022
    Values are enrichments 6 SE, expressed as tracer-to-tracee ratio (t/T). a-v, arteriovenous; PRE, value when essential amino acidcarbohydrate
    (EAC) drink was consumed before exercise. POST, value when EAC was consumed after exercise. Rest, mean value for resting
    time period. Exercise, mean value during exercise bout. 1 H Post-Ex, mean value for samples taken 0–60 min after exercise bout. 2 H Post-Ex,
    mean value for samples taken 60–120 min after exercise bout. *Significantly different from Rest, P , 0.05.
    Fig. 3. Muscle free intracellular concentration (IC) of phenylalanine
    for 4 muscle biopsies during PRE and POST trials. *Significantly
    different from biopsy 1 (rest), P , 0.05.
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    0.20). Similarly, the mean amount of phenylalanine
    taken up during the final 2 h after EAC ingestion (i.e.,
    during exercise and the 1st h after exercise for PRE
    and the 2 h after exercise for POST) in each trial was
    195 6 37 mg for PRE and 130 6 45 for POST, P 5 0.14.
    Phenylalanine Kinetics
    Figure 5 summarizes phenylalanine Ra, Rd, and NB
    for each time period during PRE and POST trials.
    Phenylalanine Ra did not change significantly from
    resting levels during or after exercise in either PRE or
    POST. PRE and POST Ra values were not statistically
    different at any time point. Rd increased from Rest in
    the hour immediately after EAC consumption by 216%
    during PRE (exercise) and by 60% during POST (1st h
    after exercise) trials. PRE Rd was significantly greater
    than POST Rd during exercise and in the 1st h after
    exercise. Rd was not different for PRE and POST in the
    2nd h after exercise.
    During PRE, NB changed from negative at rest to
    positive values during exercise and the 1st h postexercise.
    During POST, NB was negative at rest and during
    exercise but increased to positive values after exercise,
    when the EAC drink was consumed. NB during POST
    immediately returned to zero in the 2nd h after exercise.
    NB was significantly greater during exercise and
    in the 1st h after exercise in the PRE trial than in the
    POST trial.

    DISCUSSION

    This study was designed to determine whether the
    response of muscle protein metabolism to an EAC
    solution was different if consumed immediately before
    resistance exercise rather than immediately after resistance
    exercise.
    Ingestion of EAC changed net muscle
    protein balance from negative values, i.e., net release,
    to positive net uptake, in both trials. However, the
    total response to the consumption of EAC immediately
    before exercise was greater than the response when
    EAC was consumed immediately after exercise
    . Furthermore,
    it appears that the change from a catabolic
    state in the muscle to an anabolic state was primarily
    due to an increase in muscle protein synthesis.
    In the present study, the effectiveness of the drink
    appeared to be greater when it was consumed immediately
    before exercise (PRE) compared with immediately
    after exercise
    (POST). Approximately 209 6 42
    mg of phenylalanine were taken up across the leg in
    the PRE trial, whereas only 81 6 19 mg of phenylalanine
    were taken up during POST. Whereas the response
    of muscle protein metabolism increased dramatically
    and then declined within 1 h to basal levels
    after EAC consumption in the POST trial, the response
    was sustained in the PRE trial. Net balance increased
    during exercise, declined slightly, and then increased a
    second time after exercise when the drink was consumed
    before exercise. The length of the effect, plus
    higher blood flow during exercise in the PRE trial,
    resulted in significantly greater total uptake over the
    entire study period.

    In this study, the primary end point was to examine
    the impact of the timing of EAC ingestion in relation to
    resistance exercise on net muscle protein synthesis
    and, as a result, the accretion of muscle. Thus the
    response over the entire 3-h study period is the most
    appropriate to compare between trials. On the other
    hand, it could be argued that the results are biased
    toward the PRE trial by calculating the data over the
    entire 3-h study period. During PRE, the entire 3 h
    follows the consumption of EAC, whereas during
    POST, only 2 of the 3 h follow EAC ingestion. As a
    result, we also calculated the uptake across the leg
    over only the final 2 h after exercise of each trial, i.e.,
    the 2nd and 3rd h after EAC ingestion during PRE and
    the 1st and 2nd h after EAC ingestion during POST.
    Calculated this way, the gap between the trials narrowed,
    but the mean uptake across the leg was still
    *Significantly different from POST (P 5 0.013).

    Table 2. Mean blood flow and delivery of phenylalanine to the leg for PRE and POST trials
    Rest Exercise 1 H Post-Ex 2 H Post-Ex
    Blood flow, mlzmin21 z100 ml LV21 PRE 4.5960.58 19.4662.24* 7.6461.73* 5.1460.74
    POST 3.6760.46 11.0561.28*† 4.7260.36*† 3.3560.32
    Phe delivery, nmolzmin21 z100 ml LV21 PRE 253632 1,8906396* 8286129* 539680
    POST 191628 654680*† 506697*† 341659
    Values are means 6 SE. Delivery of phenylalanine to the leg is calculated by blood flow 3 arterial concentration. LV, leg volume.
    *Significantly different from Rest, P , 0.05. †Significantly different from corresponding PRE value, P , 0.05.
    Table 3. Mean arterial insulin levels during 4 time
    periods for PRE and POST trials
    Rest Exercise 1 H Post-Ex 2 H Post-Ex
    PRE 4.560.5 18.565.7 22.066.2 6.262.0
    POST 4.160.8 8.562.4 27.065.8 6.661.2

    Values are means 6 SE, expressed in IU/ml. Both PRE and POST
    were significantly different across time, but individual significant
    differences were not identifiable.

    E202
    80% greater for PRE than for POST (244 6 120 mg vs.
    130 6 45 mg, respectively), although the difference did
    not reach statistical significance (P 5 0.09). If anything,
    comparing only the final 2 h of each trial biases
    the results toward favoring the POST trial, because the
    1st h after consumption of EAC during PRE is ignored.

    Nonetheless, it is still evident that consuming EAC
    before exercise is more effective than after exercise.
    Fig. 5. Muscle phenylalanine rate of appearance
    from muscle (Ra), phenylalanine uptake from blood
    (Rd), and net phenylalanine balance across leg
    (NB) for 4 time periods during PRE (open bars) and
    POST (solid bars). Rest, mean of 3 resting values.
    Ex, mean of 4 samples taken during resistance
    exercise. Hr 1 PE, mean of 4 samples taken during
    the 1st h after exercise. Hr 2 PE, mean of 3 samples
    taken during the 2nd h after exercise. *PRE
    significantly different from POST, P , 0.05.
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    Effectiveness of the timing of EAC ingestion is supported
    by comparing the amount of phenylalanine
    taken up by the leg to the amount ingested in each
    trial. During PRE, ;21% of ingested phenylalanine
    was taken up by the leg, thus ;42% by both legs. The
    proportion was much lower during POST, ;8% across
    one leg or 16% for both legs. When EAC was consumed
    1 h after exercise, ;125 mg of phenylalanine were
    taken up across the leg (21), or about one-half of the
    value found when EAC was consumed before exercise.
    This represented ;11% of the ingested phenylalanine
    for one leg, or 22% for both legs. When amino acids
    were infused over a 3-h period after exercise, ;34% of
    the infused amino acids were taken up across both legs
    (6). Clearly, EAC consumption before exercise is more
    effective than after exercise.
    These data do not allow us to determine definitively
    the reasons for the greater response of net muscle
    protein synthesis to consuming essential amino acids
    plus carbohydrates immediately before exercise rather
    than after exercise. However, it is likely that the
    greater delivery of amino acids to the muscle during
    PRE accounts for the greater net uptake than during
    POST. During exercise in the POST trial, net muscle
    protein balance, as well as phenylalanine Rd, an index
    of muscle protein synthesis, was unchanged, whereas
    in the PRE trial, phenylalanine Rd and NB were increased.
    Consuming a source of amino acids before
    exercise increases amino acid availability. Providing
    amino acids at a time when blood flow is elevated, such
    as during the exercise bout, maximizes delivery to the
    muscle. Previous studies have demonstrated that muscle
    protein synthesis is related to amino acid delivery
    to the leg (5, 6, 27). Phenylalanine delivery during
    exercise in the PRE trial was increased 6.5-fold over
    resting levels and was more than twice that of POST.
    Furthermore, delivery remained elevated after exercise
    during PRE to a significantly greater extent above
    that during POST. Similarly, in our previous study,
    amino acid delivery was increased by EAC ingestion at
    both 1 and 3 h postexercise (21) to levels comparable to
    those obtained when EAC was consumed immediately
    after exercise. Thus consumption of amino acids before
    exercise results in greater amino acid delivery than
    when they are consumed at various time points after
    exercise, likely accounting for the greater response of
    net muscle protein synthesis demonstrated during the
    PRE trial.

    Previously, we showed that hyperaminoacidemia
    elicited by intravenous infusion of mixed amino acids
    (6) and oral ingestion of both mixed and essential
    amino acids (27) resulted in net muscle protein synthesis
    after resistance exercise. In these studies, ;40 g of
    amino acids were provided steadily over a 3-h period.
    We also demonstrated that nonessential amino acids
    are unnecessary to stimulate net muscle protein synthesis
    at rest (28) or after exercise (27). Subsequently,
    we examined the response of muscle protein metabolism
    to ingestion of a smaller amount of essential
    amino acids plus carbohydrates (21) identical to the
    one used in the present study. Similar levels of net
    muscle protein synthesis resulted when subjects consumed
    the bolus amino acid-carbohydrate solution at
    both 1 and 3 h after exercise (21). Taken together with
    the present results, it is clear that a relatively small
    amount of essential amino acids, combined with carbohydrates,
    is a potent stimulator of net muscle protein
    synthesis when given either before or at various times
    after resistance exercise.

    It is not possible to delineate the effectiveness of the
    separate components of the drink from this study. We
    have previously demonstrated that muscle protein synthesis
    is stimulated by essential amino acids alone (27,
    28). Even single essential amino acids in a flooding
    dose may stimulate muscle protein synthesis (24). It is
    more difficult to assign a role to insulin in the change
    from net negative protein balance to positive protein
    balance. After exercise, insulin seems to be necessary
    for protein synthesis to occur (11, 12, 14), yet increased
    insulin does not stimulate muscle protein synthesis
    (7).
    However, elevated insulin after resistance exercise
    does diminish the increase of muscle protein breakdown
    in response to exercise
    (7). Consistent with this
    notion, during the present study, phenylalanine Ra, an
    index of muscle protein breakdown, did not increase
    after exercise in either trial. Thus stimulation of muscle
    protein synthesis by essential amino acids, in addition
    to inhibition of the normal postexercise rise in
    breakdown, likely accounts for the effectiveness of the
    EAC drink for stimulating net muscle protein synthesis
    after resistance exercise.

    Determination of the response of the muscle in the
    present study is based primarily on uptake of phenylalanine
    across the leg. It is assumed that phenylalanine
    uptake corresponds to accretion of muscle protein.
    However, it is possible that all of the amino acids taken
    up by the muscle are not incorporated into protein, but
    instead some fraction of the uptake simply expands the
    muscle free intracellular pool. The amino acids could
    then be released at some time after the conclusion of
    the measurements, without ever being utilized for
    muscle protein synthesis. Thus it is possible that net
    uptake overestimated the extent of net muscle protein
    synthesis. However, even if we assume the unlikely
    circumstance that all of the phenylalanine remaining
    in the muscle intracellular pool at the conclusion of the
    study would be subsequently released, the amount
    does not appear to be a substantial proportion of that
    taken up by muscle, especially in the PRE trial. During
    PRE, 24 6 3 mg of phenylalanine were taken up by
    muscle but not utilized for protein synthesis, in contrast
    to 42 6 8 mg during POST. Thus the total amount
    of phenylalanine taken up by the leg and utilized for
    protein synthesis was ;180 mg (;86% of total uptake)
    during PRE and ;39 mg (;48% of total uptake) during
    POST. Clearly, even with this conservative estimate, a
    large proportion of the phenylalanine taken up by
    muscle was, in fact, utilized for muscle protein synthesis
    during the study, further supporting the notion that
    the EAC solution is an effective stimulator of muscle
    protein anabolism.

    In the fasted state, muscle protein breakdown exceeds
    muscle protein synthesis, resulting in a net negative
    muscle protein balance. Net positive muscle protein
    balance can result only from an increase in muscle
    protein synthesis and/or a decrease in muscle protein
    breakdown. Resistance exercise alone has been shown
    to increase muscle protein synthesis, but breakdown is
    also increased, such that net muscle protein balance
    remains negative (5). Additionally, net muscle protein
    synthesis as a consequence of hyperaminoacidemia after
    resistance exercise is primarily due to increased
    muscle protein synthesis (6, 27). In our previous study,
    increased muscle protein synthesis was responsible for
    the change from a catabolic to an anabolic state after
    ingestion of EAC at both 1 and 3 h postexercise (21).
    Similarly, in the present study, it is likely that the
    increase in NB from negative to positive after EAC
    consumption in both trials was also primarily due to an
    increase in muscle protein synthesis. Mean Rd, i.e.,
    uptake of amino acids from the plasma pool, increased
    dramatically (216 and 200% for PRE and POST, respectively)
    after ingestion of EAC. The fact that phenylalanine
    Ra, an indicator of muscle protein breakdown,
    did not change in response to EAC ingestion
    further supports the notion that the change of net
    muscle protein balance from positive to negative is
    primarily due to an increase in protein synthesis.
    In the present study, our arteriovenous tracer methodology
    has quantified only the fate of blood-borne
    amino acids (25, 29). Because the incorporation of
    amino acids from the EAC solution into muscle protein
    was of primary interest, Rd and Ra calculated using
    blood-borne amino acids seemed the most appropriate
    measures. In past studies we have utilized a threecompartment
    model of muscle protein metabolism to
    describe the effects of nutrition and exercise on muscle
    protein synthesis and breakdown (3, 5, 6, 14, 15, 27).
    However, in the present study, the combination of
    sampling in close proximity to exercise and a bolus
    ingestion of amino acids has made the use of that
    model problematic. That model requires an isotopic
    and physiological steady state, as well as a measurable
    gradient between blood and intracellular phenylalanine
    enrichment. Instead, we calculated Ra and Rd by
    use of data only from blood (25, 29). Whereas care must
    be taken in interpreting Ra and Rd values from this
    model (3, 30), it is the appropriate model to use in the
    present study. The importance of the plasma amino
    acids as a source for muscle protein synthesis is emphasized
    in this study. Therefore utilization of Rd was
    the appropriate parameter with which to compare the
    effects of the timing of ingestion of the EAC drink.
    Moreover, utilization of the blood-borne precursor for
    measurement of Rd allows us to relate these values to
    net muscle protein synthesis determined by phenylalanine
    uptake.

    The ingestion of a relatively small amount of essential
    amino acids, combined with carbohydrates, is an
    effective stimulator of net muscle protein synthesis.
    The stimulation of net muscle protein synthesis when
    EAC is consumed before exercise is superior to that
    when EAC is consumed after exercise
    . The combination
    of increased amino acid levels at a time when blood
    flow is increased appears to offer the maximum stimulation
    of muscle protein synthesis by increasing
    amino acid delivery to the muscle and thus amino acid
    availability.

    We thank the nurses and staff of the General Clinical Research
    Center (GCRC) at the University of Texas Medical Branch in
    Galveston, TX. We also thank Dr. J. Rosenblatt for statistical assistance,
    and the volunteers who participated in the studies for their
    time and hard work.

    This work was supported in part by Grants 8940 and 15489 from
    the Shriners Hospitals for Children and National Institutes of
    Health (NIH) Grant R01–38010. Studies were conducted at the
    GCRC at the University of Texas Medical Branch at Galveston,
    which is funded by a grant (M01 RR-00073) from the National Center
    for Research Resources, NIH.

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  22. #47
    Banned Slim Schaedle's Avatar
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    http://www.ncbi.nlm.nih.gov.proxy.li...ubmed_RVDocSum


    Med Sci Sports Exerc. 2006 Nov;38(11):1918-25. Links

    Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy.Cribb PJ, Hayes A.

    Exercise Metabolism Unit, Center for Ageing, Rehabilitation, Exercise and Sport; and the School of Biomedical Sciences, Victoria University, Melbourne, Victoria, Australia.

    PURPOSE: Some studies report greater muscle hypertrophy during resistance exercise (RE) training from supplement timing (i.e., the strategic consumption of protein and carbohydrate before and/or after each workout). However, no studies have examined whether this strategy provides greater muscle hypertrophy or strength development compared with supplementation at other times during the day. The purpose of this study was to examine the effects of supplement timing compared with supplementation in the hours not close to the workout on muscle-fiber hypertrophy, strength, and body composition during a 10-wk RE program. METHODS: In a single-blind, randomized protocol, resistance-trained males were matched for strength and placed into one of two groups; the PRE-POST group consumed a supplement (1 g x kg(-1) body weight) containing protein/creatine/glucose immediately before and after RE. The MOR-EVE group consumed the same dose of the same supplement in the morning and late evening. All assessments were completed the week before and after 10 wk of structured, supervised RE training. Assessments included strength (1RM, three exercises), body composition (DEXA), and vastus lateralis muscle biopsies for determination of muscle fiber type (I, IIa, IIx), cross-sectional area (CSA), contractile protein, creatine (Cr), and glycogen content. RESULTS: PRE-POST demonstrated a greater (P < 0.05) increase in lean body mass and 1RM strength in two of three assessments. The changes in body composition were supported by a greater (P < 0.05) increase in CSA of the type II fibers and contractile protein content. PRE-POST supplementation also resulted in higher muscle Cr and glycogen values after the training program (P < 0.05). CONCLUSION: Supplement timing represents a simple but effective strategy that enhances the adaptations desired from RE-training.

    PMID: 17095924 [PubMed - indexed for MEDLINE]
    Last edited by Slim Schaedle; 03-27-2008 at 12:55 AM.

  23. #48
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    Obviously, the relevant application of what is discussed below, depends on the degree of glycogen maintained by the athlete. (amount of lean body mass vs. overall consistent carbohydrate intake)

    J Sci Med Sport. 1998 Dec;1(4):195-202.Links

    1997 Sir William Refshauge Lecture.

    Skeletal muscle glucose metabolism during exercise: implications for health and performance.
    Hargreaves M.

    School of Health Sciences, Deakin University, Burwood, Australia.

    Skeletal muscle glucose uptake and metabolism are major determinants of whole body glucose metabolism in response to exercise and insulin stimulation. An understanding of the mechanisms responsible for increased muscle glucose uptake under these conditions is crucial for identifying strategies that enhance insulin action and exercise performance. Regular exercise, by favourably influencing the intramuscular determinants of glucose uptake, enhances insulin action. For this reason, it is recommended in the prevention and management of disease states that are characterised by insulin resistance ("metabolic syndrome"). Increased skeletal muscle glucose uptake, as a consequence of carbohydrate ingestion, maintains carbohydrate supply to contracting muscle, at a time when glycogen levels are reduced, and is associated with enhanced performance. Thus, both health and exercise performance are influenced by the metabolism of glucose within skeletal muscle.

    PMID: 9923727 [PubMed - indexed for MEDLINE]

  24. #49
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    Food for thought...

    Sports Med. 1998 Jan;25(1):7-23.Links


    Human muscle glycogen metabolism during exercise. Effect of carbohydrate supplementation.

    Tsintzas K, Williams C.

    Department of Physical Education, Sports Science and Recreation Management, Loughborough University, Leicestershire, England. O.K.Tsintzas@lboro.ac.uk

    Carbohydrate (CHO) ingestion during exercise, in the form of CHO-electrolyte beverages, leads to performance benefits during prolonged submaximal and variable intensity exercise. However, the mechanism underlying this ergogenic effect is less clear. Euglycaemia and oxidation of blood glucose at high rates late in exercise and a decreased rate of muscle glycogen utilisation (i.e. glycogen 'sparing') have been proposed as possible mechanisms underlying the ergogenic effect of CHO ingestion. The prevalence of one or the other mechanism depends on factors such as the type and intensity of exercise, amount, type and timing of CHO ingestion, and pre-exercise nutritional and training status of study participants. The type and intensity of exercise and the effect of these on blood glucose, plasma insulin and catecholamine levels, may play a major role in determining the rate of muscle glycogen utilisation when CHO is ingested during exercise. The ingestion of CHO (except fructose) at a rate of > 45 g/h, accompanied by a significant increase in plasma insulin levels, could lead to decreased muscle glycogen utilisation (particularly in type I fibres) during exercise. Endurance training and alterations in pre-exercise muscle glycogen levels do not seem to affect exogenous glucose oxidation during submaximal exercise. Thus, at least during low intensity or intermittent exercise, CHO ingestion could result in reduced muscle glycogen utilisation in well trained individuals with high resting muscle glycogen levels. Further research needs to concentrate on factors that regulate glucose uptake and energy metabolism in different types of muscle fibres during exercise with and without CHO ingestion.

    PMID: 9458524 [PubMed - indexed for MEDLINE]

  25. #50
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    ....

    1: J Appl Physiol. 2007 Apr;102(4):1604-11. Epub 2007 Jan 11. Links
    Influence of preexercise muscle glycogen content on transcriptional activity of metabolic and myogenic genes in well-trained humans.Churchley EG, Coffey VG, Pedersen DJ, Shield A, Carey KA, Cameron-Smith D, Hawley JA.
    1School of Medical Sciences, RMIT University, Melbourne, Australia.

    To determine whether preexercise muscle glycogen content influences the transcription of several early-response genes involved in the regulation of muscle growth, seven male strength-trained subjects performed one-legged cycling exercise to exhaustion to lower muscle glycogen levels (Low) in one leg compared with the leg with normal muscle glycogen (Norm) and then the following day completed a unilateral bout of resistance training (RT). Muscle biopsies from both legs were taken at rest, immediately after RT, and after 3 h of recovery. Resting glycogen content was higher in the control leg (Norm leg) than in the Low leg (435 +/- 87 vs. 193 +/- 29 mmol/kg dry wt; P < 0.01). RT decreased glycogen content in both legs (P < 0.05), but postexercise values remained significantly higher in the Norm than the Low leg (312 +/- 129 vs. 102 +/- 34 mmol/kg dry wt; P < 0.01). GLUT4 (3-fold; P < 0.01) and glycogenin mRNA abundance (2.5-fold; not significant) were elevated at rest in the Norm leg, but such differences were abolished after exercise. Preexercise mRNA abundance of atrogenes was also higher in the Norm compared with the Low leg [atrogin: approximately 14-fold, P < 0.01; RING (really interesting novel gene) finger: approximately 3-fold, P < 0.05] but decreased for atrogin in Norm following RT (P < 0.05). There were no differences in the mRNA abundance of myogenic regulatory factors and IGF-I in the Norm compared with the Low leg. Our results demonstrate that 1) low muscle glycogen content has variable effects on the basal transcription of select metabolic and myogenic genes at rest, and 2) any differences in basal transcription are completely abolished after a single bout of heavy resistance training. We conclude that commencing resistance exercise with low muscle glycogen does not enhance the activity of genes implicated in promoting hypertrophy.

    PMID: 17218424 [PubMed - indexed for MEDLINE]

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