Long runs and the anaerobic threshold

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Barefooters
May 13, 2010
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Is there validity to the concept of never passing into the anaerobic threshold during a long run? I noticed Jason has mentioned he likes to do fartleks occasionally in a long run, but does that lead to a greater depletion of glycogen and more soreness over the run?
 
No, just the opposite... I get less soreness. The more biologically-adept may be able to give a better explanation, but changing speeds seems to change up muscle activation patterns, which reduces fatigue. Terrain also plays a role, though. Almost all of my long runs over the last year or so have been on trails, most in mountains. Keeping a steady pace is impossible, and I really like busting out the occasional sprint.Oddly, I don't notice a significant difference in the point of glycogen depletion. I reliably hit a wall around 13-16 miles regardless of pace or consistency if I'm not consuming calories.

As far as the actual training aspect, I don't know that I have enough data. I'm faster than I was back in my "constant speed long run" days, but there's a lot of other variables that could affect it.
 
Man... I leave for a few months and everybody gets all serious like...

Ive ran a few 20 milers and not hit a wall, but I dont have enough experience to really say wether or not I was glycogen depleted as Im noy sure on the difference between glycogen depletion and just being tired...
 
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I would say it depemnds where you are in your training plan overall. I'm in favour of the macro-cycle approach where you have a part of the year almost exclusively aerobic, and getting closer to threshold and going over it in racing season (very simply).

So as with Jason, I think Fartlek type running definitely has a place within a training cycle, the trick is to put it in the right place.

For me, at the moment my shorter runs (10km or so) are at higher pace than my long runs, but still not going anaerobic. I'm thinking of throwing in a few speed sessions now in the build up to my July ultra as my long run capacity is going to be limited by work travel for the next few weeks and the speed work should give my legs a bit of stress similar to a longer run.
 
I would say it depemnds where you are in your training plan overall. I'm in favour of the macro-cycle approach where you have a part of the year almost exclusively aerobic, and getting closer to threshold and going over it in racing season (very simply).

So as with Jason, I think Fartlek type running definitely has a place within a training cycle, the trick is to put it in the right place.

For me, at the moment my shorter runs (10km or so) are at higher pace than my long runs, but still not going anaerobic. I'm thinking of throwing in a few speed sessions now in the build up to my July ultra as my long run capacity is going to be limited by work travel for the next few weeks and the speed work should give my legs a bit of stress similar to a longer run.
 
I'm just getting to the end of Matt Fitzgeralds Run book and once of the questions he answers is how to get a more graceful running stride and his answer is interesting, just by running more and pushing yourself into the fatigue zone your body adapts to make you more efficient (better stride) so that next time you use less energy to cover the distance. At the end of 22km today I was feeling a bit tired but I know next time it will be easier according to my watch I burned 1,540 calories. Last week covering that distance I burned 1,568 calories, hey maybe I'm more efficient.

Neil
 
Neil- Fitzgerald's comments bring up an interesting point: What is more important, good form or good training? Most runners (not necessarily us) more or less ignore form and work entirely on different training regimens. Personally I believe an efficient running form is more important than the type of training. I have also noticed most people's running form improves as they speed up. I have yet to see an ugly sprinter... but I DO run ultras. My sample size is quite small. This would seem to support Fitzgerald's observations.
 
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I read your blog post Jason, I had no idea you actually run close too 100% efforts on your long runs. I'm not sure I could actually handle that?

I experimented a little over the weekend and a couple of weekends ago on the same trail. The first time I ran the whole time, hills included and if the hill was short enough I ran fast up them. This weekend I walked up all the hills with decent grades. I have to say this weekend felt much better and after the run and the next day I was a lot less sore. For now I'll probably stick with the slower route as I will be running mostly at elevation this summer. However for this fall I will start doing more speedwork on long runs as I have a bunch of 18-25ks planned and I should be able to sustain pretty decent speeds over these distances.
 
Hey Buzz, I only run for short periods of time close to max, and not on every uphill. I tend to do it more toward the end of a run so I don't kill myself too early. The closer I get to races, the slower I go (for the same reason you mentioned). This is what my run yesterday looked like in regards to elevation, heart rate, and pace:
 

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That run was so un-maff like haha, 190bpm that is pretty impressive.

You were booking downhill too, out of curiosity what kind of speeds do you normally keep on a gradual (not too technical) downhill on a 50 miler?

Alright I'm heading out to do a fartlek for lunch.
 
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Man... I leave for a few months and everybody gets all serious like...

Ive ran a few 20 milers and not hit a wall, but I dont have enough experience to really say wether or not I was glycogen depleted as Im noy sure on the difference between glycogen depletion and just being tired...

Yeah you missed those classes,the ones on glycogen depletion and a couple others:D
 
In a 50 miler I tend to be fairly conservative on downs. On a gradual non-technical downhill I'd probably be slightly over an 8:00 pace. On technical stuff the pace drops closer to 9-9:30... sometimes well over 12:00 for the really gnarly stuff. I have been experimenting with sub-7:00s for downhills in 50k's, but it beats me up a lot. I don't think i could sustain that for a 50 miler.
 
Found an interesting article that briefly touches on the subject.
http://www.scienceofrunning.com/2012/04/why-timing-matters.html#more

"Another quick example, is the timing of long runs or runs following long runs. When we are looking at training adaptation signals, one is a decrease in muscle glycogen. Once we are low on glycogen, some sweet adaptations take place to signal our body to deal with this better next time. It depends on the case, but sometimes it’s a good thing to train low. So there are two ways to look at this beyond relying on the long run to get the glycogen decrease effect. If we look at doing a long run and then 10hr later (i.e. long run in evening followed by next morning run), the glycogen stores certainly aren’t restored. So using a long run followed by an easier but still relatively long run is a good way to get double the low glycogen (i.e. 17mi followed by a next morning 10miler). Another option which I employ occasionally with my runners is the Friday workout followed by the Saturday long run. The Friday workout (especially if its something like a threshold run) can decrease glycogen just enough so the next day you’re starting with low stores and can dig a little deeper into glycogen depletion on the following days long run. It’s a great way to increase strength endurance."
 
Is there validity to the concept of never passing into the anaerobic threshold during a long run? I noticed Jason has mentioned he likes to do fartleks occasionally in a long run, but does that lead to a greater depletion of glycogen and more soreness over the run?
I think the key is the length of the period that you are anaerobic during your long run. If you are cranking out a 5k PR from mile 10 to 13 during a 20 mile run then that probably won't work out so well for you. However, just going anaerobic for short spurts isn't that big of a deal. As Jason pointed out, it mixes things up and engages different muscles. Also, my brother is big on HIIT training and claims that it causes your body to release different hormones and what not. Maybe the same concept applies when going anaerobic during your long run? You get a burst of something from your system that isn't normally produced during a LSR.

I have found that over the last couple of years that I have developed the ability to go anaerobic during long runs and not really have any negative impacts. I guess I have developed the ability to "recover" on the go. I think that doing speedwork and esp. stuff like fartleks and float workouts have really helped in that area.
 
Agreed BH. I don't hit anaerobic for long periods of time, especially on longer runs. I also stop A LOT, so there's significant recovery. It's also worth noting- I do the fartleks because it's fun, not necessarily because it is a superior training method. The fact that it keeps me motivated is really what makes it effective for me.

As far as the glycogen depletion, I just fast occasionally before long runs. Well, I used to fast. I stopped after I realized I could eat enough in most races to adequately replenish lost glycogen.
 
First off I am not really sure about the implied link between glycogen depletion and soreness after a session. AFAIK the soreness derives from intra muscular tissue damage. A general feeling of fatigue however is almost certainly strongly correlated to the level of glycogen depletion.

As for using Anaerobic bursts in Aerobic training, if you enjoy them and they make it possible for you to do the long Aerobic sessions then you deffinately should keep them. However there is some evidence to suggest that Anaerobic work either in the same session or in seperate sessions can hinder the Physiological changes your trying to stimulate with the Aerobic work.

If your primarily interested in getting to a glycogen depleted state then running at a faster pace will achieve that quicker than running at a slower pace, so including anaerobic phases into a long run will deplete glycogen faster than a constant pace.

If you run slow enough, then you will fall out of the glycogen metabolism range altogether and into fat metabolism, at those paces its possible to just keep on going regardless of your glycogen levels. (untill the impact forces have created enough physical damage to your skeletal-muscular system that your forced to stop )

The purpose of training Low is to get to the point where you are required to run in the fat metabolism zone, which over time has the effect of making you more efficient at it, and rasing the speed at which you can run while still relying on fat as the primary energy source. As an ultra runner this is where you probably want to invest the majority of your training. Running form can still be worked on quite effectively with short sprints of around 10 seconds that dont flood the body with lactate.
 
Keep in mind, my training is entirely based on 100 miler prep. The race pace is so slow, both aerobic and anaerobic fitness isn't a huge priority. The purpose of my training is more about preparing the musculo-skeletal system for the rigors of traversing difficult terrain all day and all night (and usually part of the following day). There's no possible way to come close to matching those conditions in training. Even a long run of 30+ miles or back-to-back long runs can't mimic the conditions.

The problem with low heart rate training is the lack of stress. It's easy on your body. If that's all you do, the long distances will be brutal (speaking from experience). Stressing the body using intense running and crosstraining (HIIT) does wonders to condition the body for the stress associated with really long distances.

Personally I think training in the fat metabolism zone is overrated. With no training, our body has enough glycogen to run anywhere from 13-25 miles at typical race pace without depleting the glycogen stores. At that point, you have to consume calories to avoid a crash or slow down so you're in the fat metabolism zone. Even if you optimize your body, that fat metabolism zone pace is too slow to beat cutoffs in pretty much any race. A better strategy would be to work on speed and developing the ability to eat on the run. Improving that "fat metabolism" pace would be helpful, but it's not going to set any course records.
 
Personally I think training in the fat metabolism zone is overrated.
+1
I don't think it is worthless training, I just believe that we should balance out our training more instead of only working one side of cardio. We most definitely did both as a species early on. You can bet that we had to sprint at times to keep up with our prey so we did not lose them or to get away from predators and we most definitely ran slow and steady at times with persistence hunting.
 
Here is what made me start thinking about this issue. From the website http://www.dclundell.net/running/info/train100.html

"Calories, let me start by giving some facts. You will burn a good 12,000 calories in order to finish Leadville. Your body can provide around 1,800 from Glycogen and possibly another 2,200 without much trouble from fat. That means you need to consume 8,000 calories from outside. If you don't, the body needs to continue burning fat but you won't feel like moving at a rate that's worth much. In addition, your body will also be using muscle for protein requirements. If you use an energy drink, you can get another 3,000 calories if it isn't overly diluted. The remaining 5,000 calories must come from food. That's 500 calories per aid station. That is a lot, I strongly suggest you have a plan to eat that much."

and

"After the crossings you should continue running until you hit the trees, at that point, it will be straight up for 3,400 feet. There are many strategies about climbing Hope. The fact is, you need to get on top and it is going to take a lot of energy. My suggestion, which is part of the strategy is to arrive here fresh, then push it hard until you're at the top. Go as fast as you can without going anaerobic. If you have to stop and rest, you've gone anaerobic. Find a pace that you can continue non- stop until you get to the top. Keep pushing the pace but not so that it forces you to stop. There have been many suggestions to synchronize your breathing with your pace. I think it is a good idea, it really helps with your rhythm."