Question:
My question is, I am not wanting to win that half marathon, just run through it. Would it be sufficient to try to run for, say, 1-1.5 hours and see if I am too tired by the end?
I’d recommend getting in a couple of runs about 9-10 miles long. You may run slower in training than the race, so the duration of the training runs could be pretty similar to the duration of the race. Is it possible to do on a low carb diet, given that I am in a reasonable average condition?
It’s probably advisable to take some carbs before, after, and possibly during a long run. Keep in mind that the long run burns an enormous amount of calories. You’ll be burning 1500 calories or more. 100 grams of carbs is small compared to what you will burn during the course of a long run. So long runs may require a temporary departure from your current practice of minimising caloric intake. There exists a point where one will runs into problems with your recovery if caloric intake is insufficient. That means that you need to start thinking more like an athlete, and less like a dieter. Or, is there a radical difference betwene running for 1 hour vs. two hours?
You burn about twice as many calories in two hours. Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
Response:
Donovan — FYI — there is a difference between "low carb" and "low calorie". "Low carb" is one of a number of weight loss diet approaches, but is also used for other reasons. The calories, if needed or wanted, can be made up in fats & proteins. bj
– Hide quoted text — Show quoted text – Is it possible to do on a low carb diet, given that I am in a reasonable average condition? So long runs may require a temporary departure from your current practice of minimising caloric intake. There exists a point where one will runs into problems with your recovery if caloric intake is insufficient.
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Is it possible to do on a low carb diet, given that I am in a reasonable average condition?
The problem is muscle glycogen levels. I can’t remember if I saw the link here or in a *Fit forum but there’s a paper out that compares muscle glycogen levels in three groups. As I recall: carboloaded runners: 60-70 (mg/g?) average diet runners: 35-40 low-carb diet: 15 You need muscle glycogen to burn fat, and you can’t refresh it fast enough by eating energy gels. (That doesn’t mean they’re worthless, just not enough to allow you to run indefinitely.) Once your muscle glycogen is exhausted you bonk. A "no starch" diet is much more relaxed than a "no carb" diet, but I would be very worried about early bonks. As others suggest try running for at least as long as you expect your race to take so you aren’t surprised. That means that you need to start thinking more like an athlete, and less like a dieter.
This can’t be overemphasized. Diet books are written for the average dufus who thinks "sustained vigorous exercise" is raking the yard for 10 minutes, not running over an hour at AT. About a month ago I attended a sports nutrition seminar sponsored by the local marathon and I learned that insulin levels spike during heavy exercise. According to low-carb diet books this is a Bad Thing since it will drive sugar into fat cells, but in reality during and shortly after exercise it drives sugar into muscle cells. The basic premise of these diets doesn’t apply, but nobody realizes this. So freely drink your sports and recovery drinks. They’re free carbs since your body is *not* going to put them into your fat cells. Bear
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Donovan — FYI — there is a difference between "low carb" and "low calorie". "Low carb" is one of a number of weight loss diet approaches, but is also used for other reasons. The calories, if needed or wanted, can be made up in fats & proteins.
Yes, I understand that. I don’t understand why he thinks this is a good idea. Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
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Donovan — FYI — there is a difference between "low carb" and "low calorie". "Low carb" is one of a number of weight loss diet approaches, but is also used for other reasons. The calories, if needed or wanted, can be made up in fats & proteins. My current diet is not "low calorie", as I eat approximately 3000 cals per day (that’s a guesstimate, but an educated one). I chose this diet to defend my 50 lbs weight loss, not to lose more weight. I lost the weight by "eating less".
I don’t see why you can’t keep to 3000 calories without eliminating carbs. Is there any religious or moral reason that prevents you from consuming carbs ? Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
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It’s probably advisable to take some carbs before, after, and possibly during a long run. Keep in mind that the long run burns an enormous amount of calories. You’ll be burning 1500 calories or more. 100 grams of carbs is small compared to what you will burn during the course of a long run. So long runs may require a temporary departure from your current practice of minimising caloric intake. You see, I want to do an experiment, can I run a half marathon while on low carb.
You probably can, but that doesn’t mean that it’s a good idea. You need to use a substantial amount of glycogen to run that sort of distance. Good point. What I am interested in, can I sustain slow running for 2 hours on fat as source of energy…
No, you can’t. Glycogen is a major contributor to energy requirements even at fairly low intensities. I don’t understand what you’re trying to achieve. It sounds to me like you’re choosing your diet based on religious reasons, instead of choosing a diet that meets the requirements of your training. Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
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You need muscle glycogen to burn fat, and you can’t refresh it fast enough by eating energy gels. (That doesn’t mean they’re worthless, just not enough to allow you to run indefinitely.) Once your muscle glycogen is exhausted you bonk. That would be for anaerobic workouts, no?
Aerobic. Obviously anaerobic burns off glycogen much faster, which is why you should run slowly until your muscles are warmed up and the Kreb’s cycle kicks in. For aerobic workouts, glucose is supplied to muscles continuously, as are fatty acids. Am I mistaken?
(Reading the question as "can’t you eat fast enough to continue running aerobically indefinitely?") There are actually two questions here. The first question is how fast you can get glucose from the blood stream and into the muscles in usable form. The second question is how fast you can get food from your stomach and into your blood stream as glucose. (Well, there’s probably a third question involving liver glycogen but two should be enough!) At this point I toss up my hands and tell you to go to a sports physiologist if you want the ultimate answer. Ultramarathoners have found a solution, but everyone else said that they’re burning glycogen faster than it can be refreshed. In the meanwhile we have sports drinks advertising how fast they can get water and carbs into your system, etc. Bear
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- Hide quoted text — Show quoted text – Is it possible to do on a low carb diet, given that I am in a reasonable average condition? The problem is muscle glycogen levels. I can’t remember if I saw the link here or in a *Fit forum but there’s a paper out that compares muscle glycogen levels in three groups. As I recall: carboloaded runners: 60-70 (mg/g?) average diet runners: 35-40 low-carb diet: 15 You need muscle glycogen to burn fat, and you can’t refresh it fast enough by eating energy gels. (That doesn’t mean they’re worthless, just not enough to allow you to run indefinitely.) Once your muscle glycogen is exhausted you bonk. That would be for anaerobic workouts, no?
For aerobic OR anaerobic workouts, the primary source of energy is glycogen, which is what you deny yourself on a low carb diet. For aerobic workouts, glucose is supplied to muscles continuously, as are fatty acids. Am I mistaken?
Part of the glycogen is stored in the muscle tissue and part comes from the bloodstream. For longer (over 30 minutes) aerobic activity, part of the energy comes from fat from the bloodstream. If your glycogen stores are reduced due to poor diet (i.e. low carb), then much more of the energy you consume during exercise must come from fat sources, or you will hit the wall. The speed you can run off primarily fat is MUCH slower than the speed you can run off mostly glycogen. Thanks. My purpose really is to find how far can I go while being on an LC diet… So, quite possibly, I would achieve suboptimal results (time to run the half marathon) while on LC, however, it would be actually a more interesting experiment to me. "can I run half marathon on LC"
It is not necessarily during a single long run where the effects of the low-carb diet is seen. If you run a single long run VERY slowly, you can likely do this for 1-2 hours, consuming enough fat to keep your diminished glycogen stores from striking zero. But there ia acatche here: Dr. David Costil, in his book, "Inside Running: The Basics of Sports Physiology" (page 63) has a chart showing the difference on glycogen stores from a low versus high carb diet while training everyday. You need 6-10 g/kg of carbs every day to keep your glycogen stores up. If you get much less than this–and you can’t recover the carbs you expended in your last workout from your diet before your next workout–your glycogen stores will gradually decline EVERY DAY until you finally bonk. It isn’t necessarily any one training session that will kill you; It is the cumulative effect of a training program. Lyndon "Speed Kills…It kills those that don’t have it!" –US Olympic Track Coach Brooks Johnson
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– Hide quoted text — Show quoted text – Donovan — FYI — there is a difference between "low carb" and "low calorie". "Low carb" is one of a number of weight loss diet approaches, but is also used for other reasons. The calories, if needed or wanted, can be made up in fats & proteins. My current diet is not "low calorie", as I eat approximately 3000 cals per day (that’s a guesstimate, but an educated one). I chose this diet to defend my 50 lbs weight loss, not to lose more weight. I lost the weight by "eating less". I don’t see why you can’t keep to 3000 calories without eliminating carbs. I would gain weight then. My maintenance level is 2400-2500 calories, I tested this with fitday logging, during my reduced calorie/moderate carb phase.
If 2400-2500 is maintenance, then why are you eating 3000 ? Anyway, whatever maintenance is, (1) I don’t see why you need to religiously eliminate carbs to stick to it, and (2) "maintenance" is going to be different once you start doing 2 hour runs. Is there any religious or moral reason that prevents you from consuming carbs ? No, the reason is that after losing weight on a calorie controlled diet, I was hungry most of the time and thinking about food too much. A sign of starvation (I have a wonderful article about mental symptoms of starvation, can post it). After switching to LC/paleo, I am not hungry, eat as much as I want, and do not gain weight — at least yet. It is a convenience thing for me, plus, it has some other likely benefits.
Yes, but it is not terribly well suited to endurance athletics. My recommendation would be to stick to your current diet for the most part, but take in carbs before and after workouts. This will *not* push you above maintenance, because the extra carbs you take in are still going to a long way short of the calories you burn during the workout. It won’t cause you to "starve" (if anything, not getting enough carbs prior to the workout is what will cause problems with recovery) Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
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– Hide quoted text — Show quoted text – It’s probably advisable to take some carbs before, after, and possibly during a long run. Keep in mind that the long run burns an enormous amount of calories. You’ll be burning 1500 calories or more. 100 grams of carbs is small compared to what you will burn during the course of a long run. So long runs may require a temporary departure from your current practice of minimising caloric intake. You see, I want to do an experiment, can I run a half marathon while on low carb. You probably can, but that doesn’t mean that it’s a good idea. You need to use a substantial amount of glycogen to run that sort of distance. Someone posted an interesting link that is of relevance. http://atkins.com/Archive/2002/1/11-902958.html Enhanced Endurance in Trained Cyclists During Moderate Intensity Exercise Following 2 Weeks Adaptation to a High Fat Diet
Consider the source. My question is, did they take in carbs prior to testing ? My understanding of this study was that the low carb group trained on a low carb diet, but took carbs prior to testing. But I can’t remember, maybe I’m mistaken. Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
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- Hide quoted text — Show quoted text – Please forgive me if my questions are extremely ignorant or too frequently asked. I read this newsgroup only occasionally. I have been running for more years than I would care to admit, always recreationally (it is a sort of addiction, I feel bad if I do not run for extended periods), although I did one 5k race last year (25 minutes 13 sec). Lost 50 lbs in 2003, but I switched to a low carb diet 2 months ago (called paleo diet, meat, vegetables, fish, nuts, eggs etc, but no starches). I used to run 30 minutes runs, and usually I was tired by the end of the run. Recently, after the diet change, I noticed that I am not really tired by the end of the run, and usually need to terminate my running due to boredom or lack of time (kid stuff). My feeling, which I am planning on verifying, is that my endurance is now better (and my knees also). Given that, I am entertaining the idea of running a half marathon, which should be about 2+ hours of running lightly, which is not a terrible leap from where I am. My question is, I am not wanting to win that half marathon, just run through it. Would it be sufficient to try to run for, say, 1-1.5 hours and see if I am too tired by the end? Is it possible to do on a low carb diet, given that I am in a reasonable average condition? Or, is there a radical difference betwene running for 1 hour vs. two hours?
You should look at the TKD (targeted ketogenic diet). Intensive exercise makes demands on the body, and it makes sense to properly fuel it for exercise. A TKD diet can be low-carb or not so low-carb, depending on your exercise workload and your preference. Whether or not there is a so-called "metabolic advantage" to low-carb diets is debatable. Less debatable is that an exercise workload changes the metabolism both during and after exercise. A TKD diet can be optimized to properly fuel muscles before, during, and after exercise. You should do your own research on it, but for me, TKD means that I always refuel the muscles within 30 mins after completing exercise with simple carbs and some protein. If I’m exercising longer than 100 mins I will take carbs during exercise. If I’m planning a long run I will eat more complex carbs than normal 24-48 hours before exercise – and drink lots of fluids. The muscles are insulin-sensitive up to 2 hours after exercise, meaning most carbs that you eat will be absorbed into them as muscle glycogen. After 2 hours, and up to 16 hours, the muscles can become insulin-resistant, meaning carbs you eat will not refuel them. The research on this is ongoing, but this holds true to my experience. Your fat-burning metabolism will take care of itself. The body will always burn fat first as a choice of fuel until the pace increases. Carbs are not evil – they are just a special form of fuel that should be understood and respected. If you’re inactive or consume too many simple carbs as a regular part of your diet, then the evidence is becoming clear that it can cause pre-diabetic syndrome and eventually type II diabetes. Carbs have been shown to help both performance during exercise, and promote healthy muscle recovery after exercise. Unless you have other health complications or are feeling particularly religious about low-carb dieting (which is irrational), then using carbs in your diet in a smart way makes sense. – Tony
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– Hide quoted text — Show quoted text – Dr. David Costil, in his book, "Inside Running: The Basics of Sports Physiology" (page 63) has a chart showing the difference on glycogen stores from a low versus high carb diet while training everyday. You need 6-10 g/kg of carbs every day to keep your glycogen stores up. If you get much less than this–and you can’t recover the carbs you expended in your last workout from your diet before your next workout–your glycogen stores will gradually decline EVERY DAY until you finally bonk. It isn’t necessarily any one training session that will kill you; It is the cumulative effect of a training program. Lyndon
You haven’t done much cell biology have you, ‘Big L’? I think a refresher course is in order.
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Let me clarify something. I normally run for 30 minutes apiece.
And let me clarify something — I’m not suggesting wolfing down candy bars, I’m suggesting the common-sense approach of taking some carbs *when* you do a long run (but not at any other time). That way, you are *not* going to go over maintenance, because the extra carbs that you take in are more than matched by the workout. i want to run a half marathon as an experiment. I would like to run very few trainig runs to see if I can do it. I hope that I would be able to run 2 hours in my current condition.
You probably could, I just don’t see why you’re going out of your way to subvert your goal with inadequate nutrition. Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
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For aerobic OR anaerobic workouts, the primary source of energy is glycogen, which is what you deny yourself on a low carb diet. Glycogen, but not muscle glycogen, right?
Yes muscle glycogen. Liver glycogen is mostly for the brain IIRC. Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
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– Hide quoted text — Show quoted text – Dr. David Costil, in his book, "Inside Running: The Basics of Sports Physiology" (page 63) has a chart showing the difference on glycogen stores from a low versus high carb diet while training everyday. You need 6-10 g/kg of carbs every day to keep your glycogen stores up. If you get much less than this–and you can’t recover the carbs you expended in your last workout from your diet before your next workout–your glycogen stores will gradually decline EVERY DAY until you finally bonk. It isn’t necessarily any one training session that will kill you; It is the cumulative effect of a training program. Lyndon You haven’t done much cell biology have you, ‘Big L’? I think a refresher course is in order.
Lyndon’s cite matchs the latest science that I have read. Why don’t you educate us Roger! -DougF
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You haven’t done much cell biology have you, ‘Big L’? I think a refresher course is in order.
They banned him after that "public masturbation" incident.
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Liver glycogen is mostly for the brain
Ah, now I understand your problem.
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– Hide quoted text — Show quoted text – Is it possible to do on a low carb diet, given that I am in a reasonable average condition? The problem is muscle glycogen levels. I can’t remember if I saw the link here or in a *Fit forum but there’s a paper out that compares muscle glycogen levels in three groups. As I recall: carboloaded runners: 60-70 (mg/g?) average diet runners: 35-40 low-carb diet: 15 You need muscle glycogen to burn fat, and you can’t refresh it fast enough by eating energy gels. (That doesn’t mean they’re worthless, just not enough to allow you to run indefinitely.) Once your muscle glycogen is exhausted you bonk. A "no starch" diet is much more relaxed than a "no carb" diet, but I would be very worried about early bonks. As others suggest try running for at least as long as you expect your race to take so you aren’t surprised. That means that you need to start thinking more like an athlete, and less like a dieter. This can’t be overemphasized. Diet books are written for the average dufus who thinks "sustained vigorous exercise" is raking the yard for 10 minutes, not running over an hour at AT. About a month ago I attended a sports nutrition seminar sponsored by the local marathon and I learned that insulin levels spike during heavy exercise. According to low-carb diet books this is a Bad Thing since it will drive sugar into fat cells, but in reality during and shortly after exercise it drives sugar into muscle cells. The basic premise of these diets doesn’t apply, but nobody realizes this.
You need to check your notes or the credentials of the person doing the presentation. Insulin levels are extremely LOW during exercise, even moderate exercise intensity. Post exercise is a great time to increase the rate of muscle glycogen synthesis. Part of it is because of caclium flux in the muscle aids in facilitating CHO getting into the muscle. – Hide quoted text — Show quoted text – So freely drink your sports and recovery drinks. They’re free carbs since your body is *not* going to put them into your fat cells. Bear
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For aerobic OR anaerobic workouts, the primary source of energy is glycogen, which is what you deny yourself on a low carb diet. Glycogen, but not muscle glycogen, right? Yes muscle glycogen. Liver glycogen is mostly for the brain IIRC. Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
Correct. The liver also supplies glucose for the blood as well.
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The study had 5 subjects. IIRC, one issue is that one participate did exceptionally well on the high fat diet which skewed the average for that situation way up. If you remove the outlier then the stats are not so favorable. There have been studies suggesting that a short span of "fat loading" can lead to endurance gains, but here is the other problems with the studies many of my colleagues produce: Who cares about endurance? Really, name an event where the goal of the event is to maintain a set intensity for as long as possible. I cannot think of one. Most athletic events either call for you to cover a set distance as fast as possible (or at least get there first–the two can be exclusive) or have a time limit on a game. Note that in the abstract that there was no difference in the groups in this lame protocol. Since there was no difference and one really needs to be able to have some intensity, why deprive yourself of the substrate that will provide fast energy for when you need to speed up.
– Hide quoted text — Show quoted text – It’s probably advisable to take some carbs before, after, and possibly during a long run. Keep in mind that the long run burns an enormous amount of calories. You’ll be burning 1500 calories or more. 100 grams of carbs is small compared to what you will burn during the course of a long run. So long runs may require a temporary departure from your current practice of minimising caloric intake. You see, I want to do an experiment, can I run a half marathon while on low carb. You probably can, but that doesn’t mean that it’s a good idea. You need to use a substantial amount of glycogen to run that sort of distance. Someone posted an interesting link that is of relevance. http://atkins.com/Archive/2002/1/11-902958.html Enhanced Endurance in Trained Cyclists During Moderate Intensity Exercise
Following 2 Weeks Adaptation to a High Fat Diet Reference: Lambert, E.V., Speechly, D.P., Dennis, S.C., et al., "Enhanced Endurance
in Trained Cyclists During Moderate Intensity Exercise Following 2 Weeks Adaptation to a High Fat Diet," European Journal of Applied Physiology and Occupational Physiology, 69(4), 1994, pages 287-293. – Hide quoted text — Show quoted text – Summary: The following information was written by Atkins professionals. This study sought to compare the effects of two weeks of a high-fat, low-carbohydrate diet (70% fat, 23% protein and 7% carbohydrate) with two weeks of a high-carbohydrate, low-fat diet (74% carbohydrate, 14% protein and 12% fat) on exercise performance. Five trained cyclists were required to perform a host of cycle tests at various intensities and lengths of time. Based on the results of these tests, exercise time to exhaustion during high intensity exercise was not significantly different between groups. However, when comparing the different diet groups? performance during moderate intensity exercise, time to exhaustion was significantly longer after subjects followed the high-fat diet, despite starting off with lower muscle glycogen content (stored glucose). Subjects in the high-fat group also had a lower respiratory quotient, indicating that they were burning fat for fuel in place of carbohydrate. Commentary: The following information was written by Atkins professionals. These findings can be applied to the Atkins Principle of Good Health. Controlled carbohydrate nutrition may improve athletic performance. Although not affecting anaerobic (high intensity) performance, a low-carbohydrate/high-fat diet significantly improved aerobic (moderate intensity) performance in trained cyclists. These individuals were able to pedal nearly 40 minutes longer than individuals eating a standard high-carbohydrate diet. Good point. What I am interested in, can I sustain slow running for 2 hours on fat as source of energy… No, you can’t. Glycogen is a major contributor to energy requirements even at fairly low intensities. I don’t understand what you’re trying to achieve. It sounds to me like you’re choosing your diet based on religious reasons, instead of choosing a diet that meets the requirements of your training. Thanks Donovan, I definitely value your input. My diet is not a religious thing, please check my previous post where I explain the reasons for my choice of diet. And, besides, as I mentioned, my low intensity endurance seems to have gotten better and not worse on LC, something I completely did not expect. i
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You need to check your notes or the credentials of the person doing the presentation. Insulin levels are extremely LOW during exercise, even moderate exercise intensity.
I’m sure I remembered it backwards – we covered a lot of material in a short amount of time. Bear
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Let me clarify something. I normally run for 30 minutes apiece. i want to run a half marathon as an experiment. I would like to run very few trainig runs to see if I can do it. I hope that I would be able to run 2 hours in my current condition. If I am unable to run that much, rather than training for half marathon, I will simply give it up.
I think you have been spending too much time in the Atkins world. So you feel that if you can’t do 1/2 thon on the energy stores of a low carb eating you will "’give it up." First off, if your eating regimen does not provide sufficient calories then what you are doing is drastically bizarre, wrong and in my opinion not healthy. As Donovan says, at least eat your carbs before, during and immediately after long runs. If the rest of the time you want to deprive yourself of an important food, then be my guest. Please don’t give me the Gi GL(load) dog and pony show. The body works on calories, too many and you get fat, too few and you lose. Yes, you can lose weight on LC, but you can also lose weight fasting or only eating cabbage soup. You argument is akin to not wanting kids and giving up sex. Yes it works but it’s overkill. The glycemic index as a cause of obesity is like the old days where all fat people claimed to have gland problems. If you can’t take up a vigorous exercise program without running out of energy and give up the exercise, then you have very strange if not unhealthy, priorities. -DougF
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There have been studies suggesting that a short span of "fat loading" can lead to endurance gains, but here is the other problems with the studies many of my colleagues produce: Who cares about endurance?
Me thank you. The term "fat loading" is Vague unless I missed some post with it being quantified. I tend to fat load before an endurance event and have found it to work well. I also make sure to get some fat during the event. By fat load I’ll have my pasta not with a red sauce but olive oil. If I have access to real food before a race I’ll have bacon with my eggs and pancakes. I don’t normally do the oil or bacon game. < Really, name an event where the goal of the event is to maintain a set intensity for as long as possible.
What are you defining as "set intensity?" Anyway, ever hear about ultra running? I think that qualifies as "endurance" and we run a long time. I cannot think of one. Most athletic events either call for you to cover a set distance as fast as possible (or at least get there first–the two can be exclusive) or have a time limit on a game.
This is like a multiple choice test with the answer a, b, both or neither. What are you trying to say? -Dougf
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< Really, name an event where the goal of the event is to maintain a set intensity for as long as possible. What are you defining as "set intensity?" Anyway, ever hear about ultra running? I think that qualifies as "endurance" and we run a long time.
I think what he’s saying is that you don’t have races where the goal is to run at 9 minutes per mile for as long as possible. Either distance is constrained (e.g. a 50 mile race) or time is constrained (e.g. a 24 hour race) but they don’t have "9 minute per mile" races. Cheers, — Donovan Rebbechi http://pegasus.rutgers.edu/~elflord/
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I think what he’s saying is that you don’t have races where the goal is to run at 9 minutes per mile for as long as possible. Either distance is constrained (e.g. a 50 mile race) or time is constrained (e.g. a 24 hour race) but they don’t have "9 minute per mile" races.
I contend that effort is maintained. If I run a race where my heart rate at 150( made up number) am I not at a set intensity? In fact I would suggest HR is a better measure than pace. -DF
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