Pre Workout Carbohydrate Consumption - ABCbodybuilding

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  #1  
Old 03-17-2007, 04:17 PM
TheMac TheMac is offline
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Default Pre Workout Carbohydrate Consumption

There has been a lot of new coaches / trainers recommending high glycemic foods pre work in order to promote an anabolic state. What research have you guys come accross on this topic and what is your opinion on it?

In my opinion I have always beleived in low GI foods pre workout in order to maximize insulin sensitivity post workout as well as ensuring that we don't go into a hypoglycemic state pre workout (insulin will push glucose into the cell causing blood glucose to be lower).
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Old 03-21-2007, 04:04 AM
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Default Re: Pre Workout Carbohydrate Consumption

I am not a big advocate of it for weight lifters. It wont have a huge impact on performance, because the majority of your fuel during exercise is coming from glycogen stores, not peripheral glucose. Since our workouts are so short, as long as we properly replenish our glycogen stores with our diet that should not be an issue.

It would make sense that it would increase anabolism: it should spare lean mass and increase protein synthesis, especially stacked with essential aminos pre-workout. But from a body composition point of view, it is clearly not conducive for fat metabolism.

I think it may be advantageous for someone like Vlad who cant seem to put on fat. [img]/forum/images/graemlins/laugh.gif[/img] But if you are concerned with fat gain, I would be cautious with this method.

Concerning hypoglycemia, if someone did this method, then I would advise sipping half of it before your workout, and the rest during your workout to avoid this issue.
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Old 03-21-2007, 04:48 PM
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Default Re: Pre Workout Carbohydrate Consumption

I agree with the above statements. I have always been a advocate of low GI carbs pre workout and after doing some research that supported otherwise, I switched for about 3 weeks to a weird "training day" diet that pushed high GI carbs especially pre workout and let me tell you it isn't very good for natural bb's...

Let my trial and error be a testiment to stick with the plain and simple truth that for 99% of us... I will always advocate low GI carbs pre workout because I do beleive it provides a steadier and longer source of energy in conjuction with a solid source of protein.
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Old 03-22-2007, 12:02 AM
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Default Re: Pre Workout Carbohydrate Consumption

I had great results from this personally but I tend to train for excessive periods (2-3 hours of lifting) so I need that second wind the carbs give me.

This is just what works for me and I know it doesn't work for everybody.
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Old 03-22-2007, 07:16 PM
MartinofSweden MartinofSweden is offline
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Default Re: Pre Workout Carbohydrate Consumption

[ QUOTE ]
...the majority of your fuel during exercise is coming from glycogen stores...

[/ QUOTE ]

Hmm, is this really so? I always thought maximal or submaximal strength efforts like sixes to tens primarily use CrP for fuel. Im having a hard time to believe glycogen would have any effect on maximal muscle strength other than by an increased intracellular pressure and possibly by an increased mental alertness. From what Ive learned maximal muscle work requires far more energy than can be converted from glycogen, even anaerobically. This is a really interesting question though. Let me know your thoughts.
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Old 03-23-2007, 03:21 AM
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Default Re: Pre Workout Carbohydrate Consumption

Good point, Martin. Let me add to my initial statement.

Studies have shown that even the most high intensity short duration exercise sessions (i.e. Wingate, which is only 30 seconds) greatly depletes intramuscular glycogen stores.

Creatine-ATP is typically the dominant energy pathway for only 10-30 seconds. Even during these seconds, glycogen is still used. But after this, glycolysis becomes the dominant pathway.

When you analyze a typical bodybuilding routine--higher reps, shorter rest, greater volume--glycogen depletion becomes a serious concern.

If you are interested in more information, read our post workout nutrition articles, particularly this one, http://www.abcbodybuilding.com/scientific.php

Then, do a search in the journal of strength and conditioning research, and you will find bundles of references which discuss this topic.

For more on fuel utilization, you will also want to read these articles, http://www.abcbodybuilding.com/cardioindex.php

[ QUOTE ]

I had great results from this personally but I tend to train for excessive periods (2-3 hours of lifting) so I need that second wind the carbs give me.

This is just what works for me and I know it doesn't work for everybody.

[/ QUOTE ]

If you are training for that long, it would definitely have a greater impact on your performance relative to say, a 1 hour session.
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Matthew 7:20
And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.
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Old 03-23-2007, 10:21 AM
MartinofSweden MartinofSweden is offline
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Default Re: Pre Workout Carbohydrate Consumption

[ QUOTE ]
Studies have shown that even the most high intensity short duration exercise sessions (i.e. Wingate, which is only 30 seconds) greatly depletes intramuscular glycogen stores.

[/ QUOTE ]

Thanks for the reply, but I still have to say I do not totally agree. The main reason for this might be differences in defining high intensity work. I agree that wingate cycling (30 sec) uses glycogen for fuel, especially during the last 20 seconds of cycling, although Id say this would be generalizing anaerobic work. Speaking of the wingate test, its a good example where the switch from anaerobic alactatic to anaerobic lactatic processes can be observed. While output during the first 10 seconds might be around 1000 watts, during the remaining 20 seconds when muscles gradually start using more glycogen, output falls to about half (in my case around 600 W towards the end of the session). At this time blood lactate levels peak (in my case 19 mMol/l)

I suppose it all comes down to how you conduct or define strength trainig. To me 30 seconds of wingate cycling is not comparable to strength training at all, not the way I conduct strength training any way. During my strength training resistance is too high and rest between sets too long for lactate to even reach threshold levels. Intensity is never below 80% of 1RM and once the accumulation of phosphat ions inhibits my ability to make another lift, I rest.

I understand that, when implementing techniques such as drop sets or prolonged exercise, muscles become more dependent on glycolysis for ATP synthesis, because the ability to maintain high intensity drastically drops, probably due to the accumulation of phosphate ions which interfere in the binding of calcium to troponin, thereby inhibiting the cross bridge cycle.

Personally I never train like this because Ive found it not to be ideal for muscle hypertrophy. The heavier I go, the more I grow. The role for carbohydrates post exercise is a different issue. I would in this case be an advocate for it, since it positively affects insulin secretion.
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Old 03-23-2007, 06:15 PM
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Default Re: Pre Workout Carbohydrate Consumption

Martin,

It sounds like you are a scientist! I think it is fantastic that you are interested in this topic. Again, the best advice I can give is to read the article I gave, and do a search in the journal of strength and conditioning research. You will literally find endless research on this topic. Here is a sample quote supporting my comments. For many more, again, refer to the sources I have indicated here.

[ QUOTE ]
Traditionally, it has been thought that short-duration high-intensity exercise is primarily supplied with energy from the muscular stores of phosphagens (adenosine-triphosphate phosphocreatine system), with glycogenolysis and glycolysis supplying minimal amounts of energy (55). Recently, glycogenolysis has been demonstrated to be an important energy supplier during high-intensity intermittent exercises, such as resistance training (54, 67, 72, 73). Recently, Haff et al. (26) reported that 3 sets of isokinetic leg extensions performed at 120s1 can reduce the muscle glycogen content of the vastus lateralis by 17%. Additionally, in the same investigation a multiple-set resistance-training session (back squats, speed squats, 1-leg squats) performed at 65, 45, and 10% of 1 repetition maximum (1RM) back squat resulted in a 26.7% decrease in muscle glycogen of the vastus lateralis. Tesch et al. (73) have also reported a 40% reduction in muscle glycogen in response to the performance of 5 sets of 10 repetitions of concentric knee extensions performed at 60% of 1RM. A 30% decrease in the muscle glycogen content of type IIab and IIb fibers in response to this protocol was also reported (73). Muscle glycogen concentration was also reported to decrease by 20% in response to the performance of 5 sets of 10 repetitions at 45% of 1RM. Similarly, Robergs et al. (67) have shown that 6 sets of 6 repetitions of leg extensions performed at 70 and 35% of 1RM can elicit a significant glycogenolytic effect resulting in 39 and 38% reductions in glycogen, respectively. Type II fibers were also demonstrated to have a greater glycogen loss when compared with type I fibers (67). Tesch et al. (72) also reported that a 26% decrease in the muscle glycogen content of the vastus lateralis can occur in response to a resistance-training regimen consisting of 5 sets of front squats, back squats, leg presses, and knee extensions. One set of 10 repetitions of biceps curls can also reduce muscle glycogen by 13%, whereas 3 sets of 10 can result in a 25% reduction in muscle glycogen (54). Pascoe et al. (65) have reported a 31% reduction in muscle glycogen content in response to leg extensions performed to muscular failure (sets: 8.0 0.7). The results of these studies indicate that muscle glycogen is an important fuel source during resistance training and suggest that glycogen depletion is dependent upon the total amount of work accomplished.

Resistance-training sessions that center on higher repetition schemes (812 repetitions) and moderate loads such as those utilized during the hypertrophy phase of many athletes and bodybuilders may have a greater effect on muscle glycogen concentration than those of lower repetition schemes. However, very little research has been conducted examining the glycogenolytic effect of low-volume, heavy-load resistance-training protocols. Typical high-volume resistance training, which involves moderate to heavy loads, seems to preferentially deplete type II fibers. Because type II fibers usually express higher glycolytic enzyme activity than do type I fibers, a preferential depletion of muscle glycogen may not be totally unexpected (23). The preferential depletion of type II fibers during high-intensity exercise (24, 78), such as resistance training, may compromise the performance of high-intensity exercise and ultimately lead to a decrease in performance.

[/ QUOTE ]

G. GREGORY HAFF, MARK J. LEHMKUHL, LORA B. McCOY and MICHAEL H. STONE. 2003: Carbohydrate Supplementation and Resistance Training. The Journal of Strength and Conditioning Research: Vol. 17, No. 1, pp. 187196.
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And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.
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Old 03-24-2007, 07:15 PM
MartinofSweden MartinofSweden is offline
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Default Re: Pre Workout Carbohydrate Consumption

I must say, your humbleness is truely admirable [img]/forum/images/graemlins/smile.gif[/img]. Im going to take a more thorough look at the study you refer to, and other studies relevant to this question as well. Speaking of which, are you familiar with studies in this matter that investigate fuel utilization on heavy load resistance training (in my opinion at leat 75% of 1 RM and up)? The article quoted above refers to several other studies that have investigated fuel utilization during lighter resistance traing (from what I read between 10-70% of 1RM). Although I must say some of the results presented above seem, at first glance, a bit surprising to me, especially the one by Robergs et al. It pretty much contradicts theory, doesnt it. I need to check it out further though.
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Old 03-24-2007, 08:22 PM
MartinofSweden MartinofSweden is offline
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Default Re: Pre Workout Carbohydrate Consumption

[ QUOTE ]
There has been a lot of new coaches / trainers recommending high glycemic foods pre work in order to promote an anabolic state. What research have you guys come accross on this topic and what is your opinion on it?

In my opinion I have always beleived in low GI foods pre workout in order to maximize insulin sensitivity post workout as well as ensuring that we don't go into a hypoglycemic state pre workout (insulin will push glucose into the cell causing blood glucose to be lower).

[/ QUOTE ]

According to recent studies it would be misleading to claim high GI foods promote an anabolic state; rather a diet high in carbs promotes an anticatabolic state.

"Regulation of muscle bulk protein also appears to be attuned not to a direct effect of protein but to a secondary effect of the stimulation of insulin by components of a meal, including glucose and amino acids. The nature of the involvement of insulin, classically thought of as the most important anabolic hormone, is bizarre because it appears that in adult humans insulin does not do what it does in the growing animals traditionally used for metabolic research, such as rats, mice and even pigs. In people, it appears that it is possible to stimulate muscle protein synthesis by supplying exogenous amino acids alone while maintaining (using the insulin clamp techniques) basal blood insulin concentration at the overnight fasted level."

http://ep.physoc.org/cgi/content/full/90/4/427

"In conclusion, using AA-tRNA as the precursor pool, it is demonstrated that, in healthy humans in the postabsorptive state, insulin does not stimulate muscle protein synthesis and confirmed that insulin achieves muscle protein anabolism by inhibition of muscle protein breakdown."

http://www.ncbi.nlm.nih.gov/entrez/query...t_uids=16705065

"Increases of MPS due to EAAs are associated with elevation of signaling activity in the mammalian target of rapamycin (mTOR)/p70 ribosomal subunit S6 kinase eukaryotic initiation factor 4 binding protein 1 pathway, without requiring rises of plasma insulin availability above 10 U/mL. However, at insulin of <5 U/mL, AAs appear to stimulate MPS without increasing mTOR signaling. Further increasing availability of insulin to postprandial values increases signaling activity, but has no further effect on MPS."

http://jn.nutrition.org/cgi/content/full/136/1/264S
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