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Re: "Bonk" Training. Good Idea? [Fireproof -- TT] [ In reply to ]
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TT, It's possible to bonk in three hrs or less doing low intensity ride/run. IMHO it's related to how much glycogen that is stored prior to the training and how much you replace it during.

I bonked 1:55 into my 20mi marathon training run. I think largely because the night before I only ate a grilled grouper salad. Not alot of carbs in that!!!! I ate on my run every 45min. drank gatoraid at the same time but I still bonked. I am glad I had gels with me or I would have been in bad shape. I know I never want to do it again, the marathon was a piece of cake compared to that run.
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Re: "Bonk" Training. Good Idea? [Race Bannon] [ In reply to ]
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I dont see any sense in this approach to training. You burn fat at all speeds if you stay aerob and you burn about the same amount. The only thing changing with speed is the amount of carbs used (and with that the fat percantage).

So if you average 500cal an hour (very easy training) maybe 250 is fat (very good) and 250 carbs (gives you 50% energy from fat). Uping the intensity to 750cal per hour will still let you burn 250 cal of fat (so down goes the myth of going slow to burn more fat) and 500cal of carbs.

The fat burining will go on, as long as you have enough carbs on board. (as fat metabolism need carbs) On board means in you blood, liver and muscles. In fact a little bit shorter, as the body keeps some reserve for your heart and brain. So if you store 2000cal (or 2500 on race day carbing up before) 3-4 hours of moderate intensity (750cal) training will let you bonk - which means no more fat burning.

The only way to train (at a training relevant speed - not to crawl, hike or jogg) longer than 3-4 hours therefore is, to add carbs during the training. You can ingest about 300-400 calories from carbs per hour, so you can calculate, why the normale Ironman brings everybody to the limits of energy management.

Now obviously a 3hour ride is not long enough to let you bonk if you start well nourished (so not empty in the morning) and maintain a pace under or at about 750cal per hour. Why that should have any additional training effect - except for the brain - is beyond me. Fat metabloizm is a normal function of our body, it does not have to be activated, you do not use tricks to activate oxygen takeup (breathing) either. If you want to train your body to metabolize fat for fuel, just go long and slow replacing about 200-300 cal an hour. Long is longer than 3 hours though.

Now to that idea to loose weight that way - very bad idea. The food during and after a ride is caled recovery food for a reason - to replace lost glycogen as fast as possible is of high importance for recovery and your ability to go out and burn fat again. Ingesting the exact amount of lost carbs and at least 15g of high quality protein is important for not getting sick. So if you really need to loose some weight - well no way around to saying no to dessert - sorry. Skipping recovery food and having the tiramisu in the evening wont do it.

I know RAAM winners (relay team), that never use empty stomach training, I use it in the morning for swims (the only reason being to avoid anything coming up if some intervals torture us too much ;-) ), runs under 2 hours but never for bike rides. And I ALWAYS have a reserve gel and some money to buy coke at a petrol stop with me to avoid bonking. Training bonking seems like training downhill crashing.
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Re: "Bonk" Training. Good Idea? [Jim] [ In reply to ]
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I'm not really disputing the idea that if the body has glycogen available it will have the tendency to burn it more readily, I'm questioning the statement that carbs are necessary for the continued burning of fat.

As far as I've been able to find out the metabolism of fat and of glycogen happen in separate cycles until they are both converted to pyruvate. Also as far as I can tell neither cycle is dependent on a product that is only available from the other cycle.

But I'm not a biochemist either. Two people in this thread have stated that fat burning is dependant on carbs. Just trying to find out if that's true or not.

~Matt
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Re: "Bonk" Training. Good Idea? [MJuric] [ In reply to ]
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Fat burns in a glucose flame - is the old adage I recall from physiology. But that doesn't mean the glucose has to come from carb intake. In the absence of carbs it will come from muscle tissue - not a good thing in the long term.

Although fat metabolism can be improved (eating a high fat diet for several weeks will do it too) I am not sure why you would want to become that efficient at fat burning. I started exercising years ago so I could get away with eating more and now with a focus on 6-8 bouts of exercise I have gotten so efficient I can barely eat anything extra. I have done 8 hour rides on only 600 cal. IT SUCKS.
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Re: "Bonk" Training. Good Idea? [mises] [ In reply to ]
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In Reply To:
Fat burns in a glucose flame - is the old adage I recall from physiology. But that doesn't mean the glucose has to come from carb intake. In the absence of carbs it will come from muscle tissue - not a good thing in the long term.

Although fat metabolism can be improved (eating a high fat diet for several weeks will do it too) I am not sure why you would want to become that efficient at fat burning. I started exercising years ago so I could get away with eating more and now with a focus on 6-8 bouts of exercise I have gotten so efficient I can barely eat anything extra. I have done 8 hour rides on only 600 cal. IT SUCKS.


The breaking down of muscle fibre is too slow to provide glucose during racing/exercising. Therefore we bonk. Would it be faster, you could do an ironman on water alone - just sacrificing some muscle. You can't. During rest, your theory is true of course, which is why we don't die after a weak of fasting.

The second "point" is completely pointless though. You can eat extra of course, as you burn your own fat for that calories. So during that 8 hours you still burn a minimum of 4000 calories (if you really ride), just that they come (mainly) from your fat tissue. So you can treat yourselve to your favorite food afterwards - without getting fatter - just replacing what you burned. Actually - if the figures were right - you are very lucky it is very easy to get very lean than.
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Re: "Bonk" Training. Good Idea? [adal] [ In reply to ]
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adal wrote: Training bonking seems like training downhill crashing.


I love that analogy!

Recovery is what getting more fit is all about. Yes, you have to work in order to have something from which to recover, but, during the work phase isn't the time to be restricting fuel. Restrict fuel intake during the correct time during recovery (not the first few hours, of course), and you'll get more fit, more quickly, and can still "teach" your fat-burning system to be more efficient.



Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
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Re: "Bonk" Training. Good Idea? [RipVanWinkle] [ In reply to ]
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Enlighten me.

Jim


Jim

**Note above poster works for a retailer selling bikes and related gear*
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Re: "Bonk" Training. Good Idea? [RipVanWinkle] [ In reply to ]
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Ripper wrote: It is true. The reason it is true is that although both fat and carbohydrate can be converted to acetyl-CoA and enter the Kreb's cycle, pyruvate can only be formed from carbohydrate. From there the carbons can be recycled back to glucose, or can be used to form the intermediates of the Kreb's cycle. Since the latter are continually being drawn upon for other purposes, they must be continually replenished from carbohydrates, a process called anaplerosis. This is the basis for the saying "fats burn in a carbohydrate flame."


See? Don't do the bonk training scheme. It results in a decrease of workload achieved during that ride, it could set you up for consuming your own protein stores (muscle), and it makes it harder to recover from a not-as-high-of-a-workload-as-could-have-been-possible workout. Bad news all around. Just say no.



Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
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Re: "Bonk" Training. Good Idea? [Jim] [ In reply to ]
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According to a chart in a Tim Noakes's "Lore of running" approximately 30% of energy is supplied by fat upon exercise start and may increase 62% or so after 4 hrs or so.

Of course this is dependent on ALOT of factors including intensity, athletic conditioning, pre exercise meal etc.

At intensities of 95%+ VO2max 100% carbohydrate is burned. Some research shows that fat burning alone can only sustain exercise up to 50% VO2max.

~Matt
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Re: "Bonk" Training. Good Idea? [MJuric] [ In reply to ]
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MJuric wrote: According to a chart in a Tim Noakes's "Lore of running" approximately 30% of energy is supplied by fat upon exercise start and may increase 62% or so after 4 hrs or so.


Remember, one of the reasons the fat % being burned after 4 hrs is that you've used up your initial stores of glycogen, and gluconeogenisis isn't keeping up with the demand, nor is your ingestion/processing of carbohydrates. So, your % of total energy being provided from your fat stores increases partly because your overall energy burning has decreased....because your available sugar supply has dropped.

Don't bonk.



Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)
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Re: "Bonk" Training. Good Idea? [RipVanWinkle] [ In reply to ]
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Do you have any links, books articles etc that would go into further detail on this? Preferably in non PHD terms.

Like I mentioned in another thread I've heard this before but haven't really seen anything to prove or disprove it.

Seems like this, and correct me if I'm wrong, would drive a nail into the idea of Atkins and being "low on carbs" as a good thing. As if you are in a glycogen depleted state you would not be able to burn fat either. Thus a "bonk" would not only mean an end to energy from glycogen and glucose but from fat also, leaving only protein as an energy source. And pretty much any glucose being created from protein is being used in major organs certainly not for muscle energy at that point.

~Matt
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Re: "Bonk" Training. Good Idea? [MJuric] [ In reply to ]
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Re: "Bonk" Training. Good Idea? [Fireproof -- TT] [ In reply to ]
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In the military we used to train on little to no rations. We where training ourselves to learn to operate when hungry and exhausted. It was fantastic for the mind a nightmare for the body. It made us phsicaly no stronger.

Fight like you train, train like you fight. You will be racing with ready stores of food and liquid. Train that way.

customerjon @gmail.com is where information happens.
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Re: "Bonk" Training. Good Idea? [MJuric] [ In reply to ]
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I was reading yuor posts with interest until you mentioned Atkins... ;-)

-
"Yeah, no one likes a smartass, but we all like stars" - Thom Yorke


smartasscoach.tri-oeiras.com
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Re: "Bonk" Training. Good Idea? [smartasscoach] [ In reply to ]
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Sorry didn't mean to bring in a sacred cow.


Just looking for an answer. If it is true, and I really don't know not just trying to controversial, that fat burning ceases upon the depletion of glucose/glycogen then anything that creates a glycogen depleted stated should also keep one from burning fat.

Somehow I doubt that the statement, "fat oxidation is "dependent" on glucose" is 100% true as this would mean a near shutdown situation upon glycogen depletion and or simply starvation. I suspect this as from what I've read protein simply does not provide enough energy to sustain much, if any activity.

Again from Noakes, "...only under extreme conditions such as complete starvation or prolonged excercise(especially under conditions of carbohydrate depletion) does protein's contribution reach even 10% of total energy production (Lemon & Mullin, 1980)"

This to me means that upon glycogen depletion 90% of energy is coming from other sources, not likely glycogen since it's depleted so only thing left is fat. However I have not looked up the actual (Lemon & Mullin, 1980) study so I could be wrong here too.

So even if fat oxidation is 100% reliant on glucose I suspect that there must be some other method or cycle used upon the depletion glucose.

Again I really have no idea on this and am looking for answers rather than saying anyone is correct or incorrect.

~Matt
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Re: "Bonk" Training. Good Idea? [MJuric] [ In reply to ]
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I've called RipvanWhatever arrogant before, but he knows his physiology. He's right, read above his posts.

-
"Yeah, no one likes a smartass, but we all like stars" - Thom Yorke


smartasscoach.tri-oeiras.com
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Re: "Bonk" Training. Good Idea? [RipVanWinkle] [ In reply to ]
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It's been my experience that advocates of CKD's recommend taking in some carbs before wokring out ... sometimes in the form of glucose polymers (i.e., smarties). The carbs taken in is intended only to fuel the workout. Granted these are strength-training athletes. I fail to see how a no-carb or even low-carb diet would be anywhere near optimal for an endurance athlete.

I have rarely, if ever seen a trainer advise folks to do exercise with great intensity or duration without carbs.

=======================
-- Every morning brings opportunity;
Each evening offers judgement. --
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Re: "Bonk" Training. Good Idea? [Fireproof -- TT] [ In reply to ]
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Supposedly, Danny Chew (of RAAM "fame") once did a century ride without any food or drink ("nothing passed my lips"). Sick puppy.

----------------------------------
"Go yell at an M&M"
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Re: "Bonk" Training. Good Idea? [RipVanWinkle] [ In reply to ]
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I'm certainly not disagreeing that lack of glycogen cuts ones performance. As posted in another reply some studies suggest that fat oxidation alone can only support exercise up to 50%VO2 max, which is very low intensity.

Also without doubt continued higher intensity activity after glycogen depletion will lead to the nasty symptoms you mention below. However aren't those symptoms due to the fact that continued "higher" intensity activity is taking place, activity that demands glycogen and is taking it away from organs that can only use glycogen, namely the brain?

My question doesn't lie with the idea that glycogen is necessary for certain level of activity, as undoubtedly it is, however is it necessary for lower level activity and or for the oxidation of fat at all?

For instance someone exercising at low level of VO2max after your series of exercises below. Would they suffer any ill effect? I.E. Excercise for 3 hours do 1 min repeats, no carbs then just walking for 4 hours. Would they still suffer the dizziness etc?

Again I really don't know and would like to look into it further. Any links, books, articles, studies etc would be appreciated.

~Matt

BTW I did do some searching on anaplerosis and didn't really find anything I could wrap my feeble mind around to answer the question of whether or not glucose was necessary for fat oxidation.
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Re: "Bonk" Training. Good Idea? [RipVanWinkle] [ In reply to ]
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Here is a link to the article on Bonk training that was posted Bicycling Magazine in September, 2002: http://www.wtcycling.com/BonkTraining.html

HOW TO BONK TRAIN

1. Upon waking, drink 2-3 cups of coffee, up to 45 minutes before cycling. Don't eat.
2. Ride at endurance pace- 60-70% of your max heart rate, or a casual pace that doesn't make you pant when you talk.
3. Keep it up for 20-90 minutes.
4. You can do this on consecutive days, but mix in at least one normal breakfast per week.
5. Eat your typical breakfast as soon as the ride ends.
6 . Watch the blubber ignite!!

The key feature of the technique was to limit workout/training duration time to 60-90 minutes maximum and the article even has a disclaimor from Liz Applegate, sports nutritionist at the University of California-Davis, cyclist and author of Eat Smart, Play Hard.:

"If you ride like this longer than 90 minutes, your body starts breaking down muscle and protein in organs, then you're not just losing fat, you're weakening your body."

Seems to me that most of us who do things like a spinning class, short run, weight training, swim workout or combination before work in the morning are using bonk training to some extent. Afterall, I am sure I am not alone when I say I am not going to get up an hour earlier on Monday morning just so I can eat breakfast before before heading out the door for a high intensity spin class!


Michael

¯\_(ツ)_/¯
Last edited by: ms6073: Mar 15, 04 9:58
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Re: "Bonk" Training. Good Idea? [RipVanWinkle] [ In reply to ]
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Another urban legend... That energy sources drawn upon by working muscles are somehow based on the availability of that particular fuel or energy source, not on relative intensity.

Lesson: If you want to improve your 'fat burning', strive to raise VO2max and riding/running economy so your relative intensity at any given sub max workload is less. The lower your intensity level as a percentage of your maximum capabilities, the more glycogen you'll save.
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