Lactate Threshold Deflection Point

I tried it a few times on the treadmill using my HRM. One nice thing about the Polar S-610 software is that it has the capacity built into to handle a Conconi test. It will take such a workout and automatically try to calculate the deflection point for you from the data. It will give you the graph too. I figured, might as well give it a shot.

Since I was doing this on a treadmill, I did my run attempting to hold certain speeds for a fixed time rather than trying to run a fixed distance at faster intervals. Also, I used a 1° incline to account for lack of wind resistance. In one attempt I started off at 6.8 mph and slowly worked up to 11.8 mph in increments of 0.2 mph every 50 seconds. This gave me deflection point/LT pace that was a 3 seconds per mile slower than what Daniels said it should be.

Another time I tried it looking for more data points starting off at 6.4 mph and increasing by 0.1 mph every 30 seconds up to 11.5 mph. This gave me an LT pace 3 seconds per mile faster than what Daniels said it should be.

Many people have criticized the Conconi test. Perhaps they are correct. Certainly my version had the variables of lack of wind resistance plus the fact that the treadmill speed might not have been accurate. But from running on it a lot last winter I'd say it was pretty close. I don't think it was a coincidence that the predicted LT paces hit my chart pace both times. I'll try it again this coming winter and see if the results reflect my improved physical condition

And didn't have much luck. I did this outside on the track and used a Polar AccurexII (I think) to record HR and splits. I got a nice trendline but there was never a deflection point in the graph. Same thing happened twice. I suppose I might have better luck on a treadmill, but I'd need to find a better HR monitor (I have a lower-end model now). I also recall reading (can't remember where--may have been in Daniels or Noakes) that not everyone has a clearly-defined deflection point and that this has always been a criticism of the Conconi method. Perhaps someone who's had more coffee this morning has better recall on the location of a factoid like that.

1) There is no scientific rationale for this supposed deflection point to occur. I have asked David Martin, Tim Noakes and others about it. No one can give a rationale for why this would/should occur.

2) Even in the original papers published by Conconi and others, only about 50% of the subjects got a deflection point. One criticism I have heard is that there is some art in seeing this deflection point. (To be fair, some methods for picking LT with blood lactate concentrations also has some art involved.)

3) I would recommend using 15K pace as LT pace. It is noninvasive and pretty easy to do. One can also use the pace one can maintain for one hour.

If you want to do some reading, find PubMed and do a search. You will find little support for Conconi's method in the scientific community.

As an aside, how did you manage to get through Janssen's book? That has to be one of the worst written book in the training genre. It goes beyond any language barriers; it is just so disorganized.

On the contrary, You will find plenty of support. There is a great deal of criticism as well. I actually went to the trouble of doing a search and sifting the results a while back. I replied to this exact point on the RW forum a while ago.

I'm not convinced one way or another. I tried my own test simply as an experiment. If I manage to get significantly faster and subsequent tests reveal this with any accuracy then perhaps I'll believe Conconi had something there.

Disorganized yes but the writing itself is clear. The opening discussion on energy systems is a model of clarity, I thought.

I wouldn't say I "got through" the book. I agree that it is nearly impenetrable in a lot of places. I found some of the pace tables interesting and then began to read out from there. The conconi test interests me because it speaks to my own subjective experience of training my LT. Last summer I did a lot of 5k repeat workouts in prep for a fall marathon. I felt like I got to a point where my HR kind of stagnated (around 166-169) and only if I opened it up full bore could I then push it into the 170s. (Max HR= 185) So I'd back off when I hit 170. This worked well and I PR'd in the marathon. I took the winter off to help my wife with our new baby and am just now getting back into training. I expect that my LT will now correspond to a much lower HR, given the time off. So I wondered about the Conconi protocol because I'd like to avoid training in between LT and VO2Max pace.

Average Joe, I have the S-610 and wasn't aware there was a Conconi function. I guess I need to study it a little more.

Here is a version of the test. I have not tried it yet.

http://www.brianmac.demon.co.uk/coni.htm

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Yeah it's not the most obvious thing. Here are the basics of how to do it.

First you create your test under Options >> Test Protocol >> New. This brings up the "New Protocol File" dialog. To make my test, and I chose a type of "Speed - Time" in the Type of Protocol secition. In the "method" box I chose "Conconi". In the units box, I chose MPH. If you were doing the standard type (every 200 meters or so on the track) you would choose a type of "Speed-Distance".

Then, once I had created and named this test, I went in and specified all the steps. In my case each step was a 0.1 mph increase and was held for 30 seconds. I named this protocol and saved it.

Finally, I went and actually did the workout and downloaded it to the Polar Software. Then, with the graph of the workout open, I went to Tests >> Protocol Test >>name of my test. This does all the analysis.

One thing -- be sure to download the very latest version of the Polar Software. You can get it on their website. They definitely fixed a few bugs in it.

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jtupper, since I see you were away, I thought I'd bump this again. Any thoughts?

Having done a few lactate tsts with both runners and swimmers, I have seen lots of variations in the actual blood lactate associated with what I would consider to be threshold. As B2 has pointed out ther is often a trend but no true deflection, and for followup tests I support using a standard blood lactate value to see at what % VO2max, what % HR max and what running speed is associated with a reference lactate (4.0 mmole for example). Whether or not 4.0 is your threshold you can easily watch where the regression curve passes through 4.0 and what speed that is associated with. My feeling is a true threshold is an intensity of effort that will produce a "steady state" of blood lactate accumulation (be it 3.0 or 7.5 mmole -- which is about the range many studies have shown the deflection to occur). A typical lactate profile involves a fairly short time at a progressively faster series of intensities, and look for a deflection, which can be quite subjective. Some people look for 2 different thresholds -- 2.0 mmole and 4.0 mmole. But once you have what you consider to be a deflection then you go back and try a steady 20minute effort at that supposed threshold. One of 3 things can happen -- during this 20min run periodic blood samples will show (1) a gradual increase in lactate accumulation, (2) a steady drop in blood-lactate accumulation , or (3) a relative steady state of blood-lactate accumulation. #3 seems more like a true threshold to me -- a point where clearance keeps up with production. Because of the different ways of testing and interpreting a deflection, etc. I think Luv2run has it best by using 15k race pace (for good runners at least). However, this is not too good for slower runners who take an hour to race 10K, because the pace at which you can race for about 1 hour is a better way of explaining it. Some swim coaches use a T-50 test which is the speed you can hold for an all-out 50min swim. Others use a T-30 test, with a 30-min effort. In well-trainined runners I get 86 to 88% of VO2max over and over again with a range of about 82-91% (which is a whole lot less variation than is what you can see in lactate values associated with a deflection (2.6 to 7.6)) I still like using performances to determine training intensities, because performance is what it is all about, and I am pretty convinced that two runners who both race 13:20 for 5k are pretty equal, even though one may have a threshold associated with 4 mmole and the other 6.5mmole blood lactate. Performance takes into account psychological factors as well as physiological -- so base training on performance.

jtd, ever talk to Jan Olbrecht from Belgium? If you have, what is your take on HIS LT training philosophy? What is new or more advanced in training in the last few years then let's say 15 years ago? thanks

Have not. Changes are more likely to be interpretation of research and other runners/coaches tweeking of the original stuff. Definition of terms is a major factor. I just saw an article in which a group of runners took a VO2max test, then during training (only a couple days later) exceeded their VO2max by running below VO2max intensity. Conclusion was that you stress VO2max more by working below max than at max. My definition of VO2max suggests that they didn't have VO2max in the first set of tests. This becomes even more wild when you start talking about threshold and what it is and how to use it. Where the runners and coaches are certainly free to play with findings are in the how-much and how-often categories, and those are cetainly legitimate areas for individual experimentation. This is a real area where coaching and science often should differ. Science uses group data to present probable results and those findings don't apply equally to all individuals, and many coaches and athletes would sure like them to.

Thanks, just wondered about J. Olbrecht because he has done lots of swimming research, which I know you were involved with the swimming program for a brief time.

How effective is training at slower then 15k Velocity,...lets say Marathon speed in effectively raising LT? Less stressful, no? Also I know there for a long time Owen Anderson was preaching running faster then LT as the most effectively method. Seems as though there is conflicting info as to the best way to go about the job?

very interesting correlation with LT and MaxVO2. Help me so I get this right, what VO2 speed would correspond with a 5:00 LT velocity? And, what's your sample workout for VO2. Thanks very much.

Not sure of the name, but now that you mention swimming I do believe I know the guy. As I remember we liked to argue a lot as to whether swimming in the flume was easier or harder than in a pool. I felt faster times could be achieved in the pool because of the turn opportunities. A long, but fun discussion.

help -- a pretty effective relationship between VO2max and threshold running speeds is to subtract 6 seconds per 400 meters from your threshold speed to get VO2max pace -- if threshold is 5:20 per mile for you then VO2max would be about 4:56. Also works the other way around, depending on which speed you are most confident in.

Jack, not really what I asked in my last post but thanks for posting! I really wanted to know if you thought that running below LT or above LT was more effective? Look that back over, sort of like what is the Optimizing of time & effort in gaining higher LT speeds. Thanks, jzs

I believe the jury is out on that one. Can only speculate that one; like all training studies, very difficult to do a ggod job of researching and individual differences probably abound. Clearly being above T pace will result in less time spent at that training pace and going below it will allow for more time spent, so the question is which is doing the greater good -- duration or intensity and both seem to have their place. I am trying out various combinations at present with the few runners I coach, but they are currently more marathon types so there is more willingness to do the more duration approach.