Aerobic Threshold???

I wouldn't just go off of v02max percent and heart rate. Since your aerobic threshold pace will vary depending on your economy at relatively slower speeds (it is way slower than v02max velocity and 100% max heart rate) it seems like a more accurate prediction of this pace would be off of your best marathon race pace. 140 bpm in terms of heart rate training is going to really vary between individuals, and your percentage of vo2max can also vary because you may be way more or way less efficient at slower/faster speeds.

Bottom line (what I think): Don't get too caught up in the numbers...."feel" the pace. A better rough estimate might be about 20sec per mile slower than marathon race pace. Don't worry about what the heart rate monitor is reading....you want to slowly work into "the zone." Usually this can be done by running slightly negative splits.

You are right though, I'm willing to bet that 90% of the runners out there get carried away and run way too fast. Its like they don't know the difference between the AT and the LT.

Using the term aerobic threshold makes me think of a workout. That kind of bugged me during a USATF clinic- using the term aerobic threshold. Just call it an easy day and use the 65%-75% VO2 max (or the HR numbers) as a guage. You'll find a sweet spot for your EFFORT on easy days. Probably won't be the same PACE everyday. As for the numbers, start your runs at the low end and finish at the high end (start at 130, finish at 150 if you're set on using a HR monitor). Think of it this way though: if you were to do a VO2 max test everyday, I think you'd find different #'s each day, so don't be a slave to pace/numbers.

What is it with americans and wanting to run loads of miles REALLY REALLY slowly! I never come across this anywhere but america. You want to get fast and strong do not jog around all day.

For the science, 140-160 HR is base work, milage, running. The word easy running should be thrown away. If you run at 160 this is not easy for 1 hour, its a good hours work. AT is more like 170HR, AnT 175+ VO2 and anearobic work above that. Below 140HR is what joggers do, thats the difference between training and jogging.

AT is not easy. Run at AT for 6,7,8,9,10+ mi. This is tough.

Why does USATF advocate running AT runs at approximately 65% Vo2 Max when AT pace can vary? Here is the portion of the book:

Fatty Acids are used as the primary fuel source up, for the aerobic energy system, to approximately 65% of Vo2 Max. At thtat point, 65% of Vo2 Max - defined as aerobic threshold, the primary source of fuel shifts from fatty acid to glycogen. The threshold represents the dividing line between these two substrates and their predominance. Training at or below this threshold will use fatty acids as a primary substrate and thus bring about a "glycogen sparing effect." The more aerobically trained the athlete is, the faster running tempo potential at this threshold. This adaptation occurs from an increase in intracellular triglyceride stores along with the increases in muscle capillarization and mygolobin content. As well as an increase in an activity of those aerobic enzymes responsible for the use of fatty acids as the primary fuel source.

They seem to be pretty sure that 65% is THE number, and my god is it a slow pace. From what I can understand in the book, running at this pace is suppose to MAXIMIZE gains in heart size/strength, cardiac output, capillarization and muscle cell enzymic activity. Is USATF misguided in choosing such a singular figure to achieve these goals?

eurotrain wrote:

What is it with americans and wanting to run loads of miles REALLY REALLY slowly! I never come across this anywhere but america.

Um, the article on Kenyan runners by Scott Douglas indicated that some of the best runners in the world run pretty slow at times. Also, Mottram said in the Mensracing article that he runs really slow for his easy days as well. And, if I'm not mistaken, none of the aforementioned runners are American.

First out, forget the HRs - 170 for one guy is 150 for another and 190 for yet another. You cannot set HRs for all comers - %HR max is the way to go (or %WHR/HRR as others do).

As I understand it Aerobic threshold is NOT a regular day, but a harder workout. In Hadd's "mega thread" he spoke of staying below 75% max on most days and hitting the AeT workout a just a couple of days a week.

These workouts start at around 82% HRmax and only increase in effort when there is no cardiac drift (HR not rising at constant pace in later reps). 3 x 5K reps is a typical session. Hadd reckons you can get up to 88% HRmax over time with no drift - these reps pretty much determine your marathon pace.

AeT is all about maximising fat burning. As I understand it from reading Renato's IAAF book, although you burn a higher %age of fat at slower speeds, as you run faster you actually burn a higher quantity of fat for a while, before the need for glycogen then causes that fat burning to decrease. The fat burning peak = AeT (or near as damn it!)

The advantage of raising AeT is that it preserves glycogen supplies at speed - crucial for a good marathon or as a foundation for faster running.

Running above AeT will teach the body to burn glycogen too much (esp. type IIa fibres) - this is why so many fast runners can never do a good marathon - too many miles over AeT and not enough work trying to raise it. As I understand it, this is why it is important to wait for the cardiac drift to vanishg before increasing the intesnity in these crucial sessions.

I have had great success in raising AeT in this manner and recommend it highly.

Americans may talk about running slowly, but most of them actually run faster on regular "easy" runs than much faster athletes from other countries do.

The Japanese thrive on rigorous aerobic efforts and sometimes brutal repetitions of 1,000 meters, but when they set aside a time to run easy, it's truly slow, often over 8 minutes per mile. This running is great for connective tissue. With its low-impact and reduced range of motion, the blood flow is just enough to provide a warming, soothing effect similar to a calming, relaxing bubble bath. The low-intensity exercise also uses fatty acids and helps stabilize weight and body fat.

Frank Shorter, Gelindo Bordin, Noureddine Morceli and Stefano Baldini - all Olympic champions - are said to have included some almost laughably easy trotting in their routines. Rob deCastella and Craig Mottram, cut out of basically the same mold, have also reported running slower than many recreational level wannabe runners.

The USATF numbers may be modified from guidelines supplied by jtupper, who would place "E" (easy) pace at some percentage (say 70%) of max oxygen uptake as a not-so-hard-and-fast rule of thumb. But I'd bet my house that, face-to-face, jtupper would tell an experienced runner to "run as slow as you want" on easy days.

If you fear the pitfall of becoming a plodder as a result of "too much slow running," try running your easy runs as slowly as usual (maybe even slower) but keep your usual tempo pace stride frequency, maybe around 180 steps per minute. Get a light, tapping-along feeling rather than a sluggish, sinking feeling. This way, you'll be able to get more mileage at a low-risk, relaxing pace but will retain the motor coordination necessary to prevent loss of running economy due to lazy stride mechanics.

Grasshopper say: "Learn less from book, more from the road"

Master Po say same thing.

Runningart2004 wrote:

Grasshopper say: "Learn less from book, more from the road"

We all want to believe this, it is inspring to think that faith and feeling will trump science, but it is also a gigantic fallacy. You can't go out and run how you feel and expect to make the most efficient improvements. The fact is, the body is a structrued system, and unless you train it with a structured plan, you will not maximize improvement. What is evident in this thread and factual in the real world, it that there is no scientific concensus on aerobic threshold. What is not evident is the cause of this. Is it lack of research? Inconsistency in research? Poorly designed research? I would be interested to see a summary of the various studies done on aerobic improvements in the human body. Unfortunately, I am too busy to look for them. Anyone else, however, is free to post any findings here (hint, hint)

Bump

Finding the AT is an "art."...but it is also a "science"

I'm not sure that all the runners over in kenya are aware of the AT....but they can feel it.

An aerobic threshold run could be an easy day. Its not a "hard day" by any means. Maybe you're out for a recovery run, or an "easy day"...but you feel good and start flying the last 3 miles. That could almost be considered a short AT running session...at least the last 3 miles of it.

On a true easy day/recovery day you should "jog" around. Do strides if you're worried about lack of hip mobility from it. As long as you are doing 100mpw plus, you're doing an LT and an AT session weekly, and you're doing something to turn the legs over...you're getting fit, and you can "jog" the rest of the days. You could call them "junk miles" if you want, but I count them in my log.

eurotrain wrote:

AT is not easy. Run at AT for 6,7,8,9,10+ mi. This is tough.

Actually AT is very easy. If you're having a tough time at it, you're not running at AT

nopers wrote:Actually AT is very easy. If you're having a tough time at it, you're not running at AT

I think this is a case of everyone having a different idea of what is meant by "aerobic threshold," like the word "tempo" has different meanings to different people.

I don't know if there's an accepted scientific definition for the term, but as I understand it (or use the term personally anyway), aerobic threshold is the point where you shift from burning mostly fat to burning more glycogen (I guess this is what the quoted USATF definition says, more or less). But those are some pretty vague terms ("mostly"), meaning the specific "point" of transition could be interpreted along a looooong grey scale from very easy running up to faster than marathon pace.

I think of aerobic threshold being roughly marathon pace, or the pace I can sustain without much HR drift tor 10-12 miles at about 87-90% HRmax. I think this is more or less the way Hadd used the term in his lengthy discussion of base training. That means, for me, that "AT" is a pretty brisk pace, not an easy pace.

your entire post is a series of "i guess"s and "as it means to me"s.

Aerobic Threshold is a ridiculously easy pace, if you are running hard at all, you are running too fast.

Runningart2004 wrote:

Grasshopper say: "Learn less from book, more from the road"

Clodhopper say: "Runningart2004 not much faster than in high school."

bump

I'd have to go with what "Pete" says: AT is closer to current marathon race pace....I'd say about 20sec per mile slower if you are running around 6min/mile for your AT runs. Your AT pace, when done the right way, requires a slight concentration in pace and effort....it may even feel mechanically fast. It is not a pace that I would want to (or like to) hold up for more than a 1/2 marathon during training. Actually most of my AT runs are between 6-10 miles. Again though, most runners tend to "hammer" and go way too fast (or they are horrible at estimating their current marathon race pace).

I think a good guideline for doing an AT run (besides its the point when you notice your breathing has increased to a more "steady rate" (it is still easy to talk, but you can't sing a song very well) is that you can easily run negative splits at will, and, if you pushed it you could drop your final mile pace by about a minute.