A: Easy pace should be aerobic threshold — if you are fatigued then sit under aerobic threshold

B: Steady pace for you should be 5-10 above AeT — if you are fatigued then sit on AeT

C: Endurance sessions -- start these at AeT and build up from there — no need to go more than 5 bpm above AeT.

D: In general, the shorter the session and the higher your energy — the higher up your aerobic zone you can be.

E: If you are feeling good and I have scheduled "easy" then feel free to take it to steady — steady being 0-10 bpm above AeT.

The above gives you some parameters to run your own intensity based on your energy levels. You will find (at times) that your AeT moves with your recovery situation. When your AeT is 10 or more beats below normal then you are tired and should train in your easy zone (below that day's AeT).

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Why AeT for IM?

Q: I don't understand why you are giving AeT intensity levels for base training. In my opinion the AeT range is very wide. I don't care what the millimole chart says. As long as you are aerobic, then you are under your AeT. I think the use of Zones and CP is more defined for a certain type of training effort. Why complicate things by adding another type of training regiment?

A: The main thing I am trying to help my athletes understand is their aerobic zone. CP and HR zones work quite well for my experienced athletes, however, in training side by side with my moderately experienced and novice athletes — they do not have a good concept of their aerobic zone. I am not tying it back to lactate, rather I am seeking to help them ID the bottom end of their aerobic zone. As their fitness moves throughout the season and based on their recovery, this zone moves around a bit. My main goal is to help them avoid pushing too hard on their aerobic base training. Even my experienced guys tend to take it out too hard on their endurance sessions, I am trying to give them the confidence to slow down.

NOTE: In reviewing the question, the questioner may have been thinking that I was talking about training under LTHR. My definition of the Aerobic Range was summarized in that Training Intensity eMail I sent out to the team prior to my bike tour.

NOTE 2: My original notes on this subject talked about lactate levels and I thinkthat this might have been a bit misleading to some (and premature on my part). Following additional discussion with Hellemans and a further reviewof his book on the subject. I believe that the shape of the lactate curvecontains more information than the nominal lactate levels. With John'sanalysis of my own testing, the curve has told us more than simple nominallevels. Further, lactate levels show significant variation across sportsand athletes — my aerobic run levels are a lot lower than my aerobic bikelevels.

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More on Finding AeT

Q: On the trainer if I do steady mid-level intervals (say for 5 mins+) after a few of these I get to where my breathing become deeper and rhythmic, but very steady state. Is that the onset of that AeT, or is AeT lower than that HR? I really like using breath as an indicator...

A: If you are talking about building up from easy pace then that sounds aboutright — if you know your HR zones from the Tri Bible then AeT typicallylies near the top of Zn 1 or the bottom of Zn 2.

When some people talk about rhythmic, they are normally up in what I callTempo/Mod-Hard — that is 10-20 above AeT. The deepening itself does notlead to rhythmic breathing. It is a very clear indicator when increasingfrom easy pace — it doesn't require intervals of harder efforts to getthere.

The subjective perception method can be used with other variables(pace/power/Friel Zones) to get an accurate picture.If your trainer is a CT then 60-65% of CP30 is another reasonableindicator. See my X-Tri series on power that ran a little while ago for moreon training with power.

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AeT Below Upper Zn1 in Weaker Sports

Q1: I have been mulling over some thoughts regarding running vs. cycling and wanted to share them with you and get your take. Primarily, they revolve around RPE, training zones, aerobic base, strength in running compared to cycling. As you know I have more of a running background (HS x-country and my first move back to fitness was training for a marathon). In addition, I have not performed a bike LT since last season, but I would not think that I am THAT for off.

Here are my observations:
It is pretty "easy" to get to the upper end of Z1 when running. I just start running and without too much effort, I am soon running comfortably in that range. Getting to the upper end of Z1 is "harder" when cycling. What I mean is that a comfortable riding pace for me normally places me lower in Z1 compared to running. If I want to get to a higher Z1 or Z2, it feels like it takes more effort than to do the same in running.
Running: If I keep the same effort over time, I can pretty much stay in the same zone
Cycling: Over time, what started out as easy pace becomes significantly harder over time

I may be perfectly describing a bike ME limiter, but I wonder if there is also an inherent difference in the sports. Also, I can't help but think that I should be narrowing the gap in my running vs. cycling ability by now (I don't mean this point in my season, more from a perspective of multi-year progress). My perceptions may also be a bit skewed because my typical bike session is at least 2x the length of a typical run session. Did you experience anything similar? Has it changed?

A1: This has to do with how well your muscles are adapted to the various sports. I am willing to bet that you feel like your aerobic threshold is lower than the top of Zn 1 for the bike? You are describing a bike endurance limiter, we need to get through that before ME becomes an issue.

I've experienced exactly what you describe — through 1000s of Ks, I've addressed it. It's a normal issue for us and probably the key challenge that faces us. You see, the only real way to address this is to "ride lots" and that's the toughest part of your schedule. As we build into the plan, we are going to schedule lots of easy miles on the weekends. These should help address this point.

On the bike, subjective perception is a good guideline to complement your HR zones. Personally, it takes many years to be able to ride extended periods in Zn 3 on the flats. It's surprisingly taxing and why I never recommend that level for an IM race.

Q2: Thanks for your message. You are correct — I do feel like my AeT is lower than the top of Z1. I do have a few follow-up questions regarding the endurance limiter. My misconception is that, since I've done two IM's, endurance is no longer a limiter. I must have viewed the concept of endurance incorrectly. Second, is there a lower end to "easy"? I sometimes worry that I'm not uncomfortable enough in "easy" — to one extreme, I probably shouldn't be so comfortable that I could sit back and read a book. Finally, when you say "lots of miles", I am assuming you mean together (e.g. a 25 mile ride beats 5 5-mile rides).

A2: Endurance should be assumed to be the key limiter for all IM athletes until they are at the top of their AG. In fact, I know elites with aerobic endurance as a key limiter. The Four Pillars are where it is at (my opinion).

As a cycling novice, it's normal for your aerobic threshold to be lower than the top of Zn 1 — that's one of the reasons why I have begun to advise athletes on using the subjective perception method of training zones. It's to help give the team the confidence to slow down. For you the issue is cycling, for many others it is running.

I don't think that there is a low end to easy — basically easy is where your AeT lies — if you are too tired to sit on AeT then (at your level) you are better off with total rest. There is no point in sitting below AeT. You should note that many novices can hit AeT by merely walking fast (I can hear their breathing). When I say ride lots — for you — I am talking about frequency first and duration second. You simply don't have the time for us to tackle it any other way.

You should not be uncomfortable in easy or steady. Discomfort for steady training arises due to aerobic fatigue. It is a slow process. Learning to have the focus required to avoid power spikes and surges will enhance your aerobic endurance — this will come later in the season.

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Sickness

It's winter and that means that Northern Hemisphere athletes are heading into flu and sickness season. Having been working with a number of the team for three years now, I thought that I would share my observations on the causes of illness.