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Juerg Feldmann

Fortiori Design LLC
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Posts: 1,530
 #1 
This is a nice  write  up    20 +  years  after the fact  and it is great to see, that  there is a shift in how we look traditional ideas now  with new  information's  studies  and technology.

 Even power meters  today are  more accepted. Here  a power meter  from my time in school.

Power pedal  DDR.jpg 

 . What is interesting is the difficulties  to let go on  absolute numbers  when we talk  about blood values, as  the  production  and  utilization of lactate  depends  on so many factors,  that 1 moll or  4 mmol are  great historical values (Mader et all )  but  have little  meaning really in the overall picture.
So  why do we  stick to values  and not just accept the great article below  without  any  numbers  just the  facts  on what we read ?
  As  soon you work outside  endurance sports  and for  sure  outside  the ability  to use  power or wattage , like in a   game  sport   or  in a  strength  workout  with body  weights  used only, than   you will see  how lactate values  are  all over the place  .
 Even in  cycling we  can  play  with lactate    depending on what we  try  to be limiter  and or compensator.
 We  showed  in Boulder  during  a  MOXY demo , how   when riding  at FTP  or  CP  we can play  with lactate values when  seeing Max lass values  and how it interacts  with  O2    trends in NIRS.
 Nevertheless it is a nice   beautifully  summary   on what we  discussed   as well Max Lass and  SmO2 trend  are possible  close  when  they are stable. When combining with  performance it is getting super nice  to see all of that.
 One big interesting question   for me  is  still the question.
  What limited  the FTP  performance  and or  what   changed  the FTP performance  from today   to  yesterday.
 Remember the FTP  example we showed  with the Australian  study on heat and our in house study  with carbs.
 So   finding the  limitation or     compensation   on what created  the  physical performance, is  in  rehab  at least the  key to an individual  programming .
 Here the great article  sent to me  by Bart.  
PS  look  one  interesting section   which   many start to discuss the " slow  " component. ' Think back on the team approach  and see  why we  have this slow component (  time   for teams members to get involved.  or the functional reactions  before the structural integration  ? ) 

Understanding “Threshold”

Most athletes have an intuitive idea of “threshold”. It refers to the idea that  every athlete has a point at which working just a little bit harder means having to stop a lot sooner. Over the years, there have many  explanations for this phenomenon. Like most processes in the human body,  “threshold intensity” is likely multifaceted. It is complicated by the fact that most of the people writing or talking about it don’t have a good handle on what it really is.

For starters, we have a lot of terminology that  people in sport use somewhat recklessly and inaccurately. Let me try to  help clear things up a little bit by concisely defining the “scientific” words you have heard thrown around.  In short, there are really two  “thresholds”, if you like: Lactate Threshold (LT), and Critical Power (CP). Lactate Threshold is indicative of changes in your exercising body that may be difficult to detect on a conscious level, but which we can find using specialized tests. Critical Power is probably the threshold athletes actually feel.

Let’s first get handle on lactate. It is a substance that appears in the blood during exercise. The harder you go, the more of it there is. A lot of attention has been paid to it, because it is easily and cheaply measured. However, it is really only an indirect marker of exercise intensity. Basically, your body burns a mixture of fat and carbohydrate during exercise. For many reasons, exercising harder requires your body to burn a greater amount of carbohydrate, and one of the end products of this is lactate. It isn’t a waste product, and it does not in and of itself cause fatigue. Rather, it is an energy rich compound which is taken up and utilized by other cells / organs in the body.

So, how has lactate been used to understand the relationship between exercise intensity and stress on the athlete’s body? Essentially, scientists wanted to set up some ground rules for what was easy and what was hard. They looked at the behavior of lactate in the blood at different work rates, and looked for places where things seemed to change. This lead to the definitions of things called LT, OBLA, and MLSS. There are some other, lesser used terms, but these are the ones you want to know about if you want to communicate effectively.

What I would like you to do is imagine yourself jogging along easily, or going for a spin on your bike on a long, flat road. Now, I want you to imagine slowly speeding up, and hitting all of these different levels of exercise as you go.

At the low end of the spectrum, we have Lactate Threshold or LT.  This is simply the point where the level of lactate in the blood rises by 1 mmol / L over  exercise baseline. In other words, if you are zipping along at 1.5 mmol /  L, and you speed up enough that you reach 2.5 mmol / L, you have  crossed LT. This is actually a lot easier to do than most athletes  realize. You could ride around at / about LT for a couple hours without  much of a problem.   Running, it is probably in the ballpark of your marathon pace, although elites can run a marathon a bit harder than this.

[lt1-300x154]

LT and OBLA

In the middle somewhere, we find OBLA, or Onset of Blood Lactate Accumulation. It is when you hit 4 mmol / L, irrespective of where your baseline was. This term is not used frequently anymore, and we should probably avoid it. It isn’t a great marker for many reasons, but a big problem is that it is an “absolute” level. For instance, let’s say your baseline lactate during easy exercise is 2.5 mmol / L. Hitting a level of 4 probably means something different to you than it does to someone who started at a level of 0.5 mmol / L.

At the high end, there is the MLSS, or Maximal Lactate Steady State.  This is equivalent to something like the pace you could hold for a 20 to 40k TT, or a 10k to a Half Marathon, depending upon how well trained you are. In terms of lactate, this is simply the highest level of exercise we can manage while  maintaining a steady concentration of lactate in the blood. If we try to go any harder, we see a progressive increase in lactate levels, even if we maintain a constant power or pace.  MLSS is intimately related to the concept of Critical Power (CP), and  is probably one of the biochemical manifestations of reaching Critical  Power (if you are on a bike) / Critical Speed (if you are running or  swimming or whatever). The physiological “stuff” going on at this point  is probably what results in the “feeling” of “threshold”, and is what is partially responsible for what Andy Coggan has called “FTP”. FTP is not reflective of some unique, alternative threshold phenomenon. It is just convenient shorthand,  and results from your body “understanding” that if it goes much harder,  bad stuff is going to happen (like inexorable fatigue). In other words,  FTP that you observe in the field by doing something like a 40K TT or running a half-marathon is probably pretty close to, but just slightly lower than CP in a well trained athlete.

This  begs the question, what is CP and how do you measure it? If you did a  bunch of all-out exercise tests…i.e. went as hard as you could for 3  minutes,

[cp-300x271]

Exercise tests of different duration (circles). The curve levels out at CP.

and then for 5 minutes, and then for 10 minutes, and you  graphed them on a piece of paper, you’d get a curve. It would be high on  the left, and then slope down to the right. The place where it seems to  level off is CP. You can also make the same graph by using joules (this  is easy… watts = joules per second), and you get a straight line, and  the slope of that line (rise / run) is equal to CP. If you wanted to do it running, you would run a 3k, a 5k, a 10k, and then make the same graph: the distance on the vertical axis, the time it took you on the horizontal axis. Rise / Run = Critical Speed. (PLEASE NOTE: This is Critical Power, the real scientific one, not the bastardization that is incorrectly used by many people to refer to the hardest they can go for some  period, like “CP30″ for “the hardest I can go for 30 minutes).

Basically,  it goes like this. As you cross LT, you begin burning more carbohydrates. You also begin recruiting less efficient  muscle fibers, which tend to use more glycogen / carbohydrate and less  fat for fuel by their nature. The result of this is an increase in lactate in the blood we discussed above.  This is not a problem. Like I said, the lactate is taken up by other cells / organs  and is metabolized. (Again, lactate is an energy-rich compound, not a waste  product. It doesn’t in and of itself cause fatigue. In fact, your brain, your liver, even your kidneys will actually use it for energy!) In  triathlon, it is a problem only in the sense that your body glycogen /  carbohydrate stores are limited, and that you can “bonk” if you aren’t  getting enough carbs in while you race (if the race is long enough).

Something else interesting happens above LT. We see the emergence of what is called the “slow  component” of oxygen use. In other words, let’s say your LT is 170W (not  unreasonable for an age-grouper). Below 170W, you are using some  constant amount of oxygen. If you made a graph, you’d see your oxygen  use rise up as you started, and then become a straight line, which was perfectly level. Now, if you  ride 180W, what you will see is that your oxygen use seems to kind of  level off, and then (maybe a minute or two later) there is another  “hump”. In other words, it appears as though your body suddenly realizes  it needs more oxygen to do the job. However, this second “hump” also levels off, so you again end up with a steady state of oxygen use. It is just that you are using more oxygen than you might otherwise have expected.

The key is that so long as you stay below Critical Power, your body is able to maintain a physiological steady state.  After several minutes, oxygen use levels off, and lactate concentration  levels off. In the muscles, the concentration of creatine phosphate  (PCr), ATP, inorganic phosphate and hydrogen ion (i.e. pH, or how acidic it is inside the muscle) stabilizes.  Once you go hard enough to cross Critical Power, bad stuff happens. In  other words, let’s say your CP is 240W. If you go to 250W and hold it, the result is a major metabolic upset inside the muscles . Even though the work rate is not changing, there is still a progressive increase in the amount of oxygen used, a progressive increase in lactate concentration in the blood, and a progressive decrease in ATP, PCr and pH inside the muscle. It is very cool, because you cat  actually watch a lot of this stuff happen with a specialized MRI setup.  Eventually, you reach some limiting level of these markers, fatigue, and must stop, or at the very least drop to some  much easier intensity.

So, you may now be asking yourself, “Why should we even worry about lactate?” The answer is, we shouldn’t! I encourage my athletes and students to stop thinking in  terms of lactate. Everyone does it, because it is so easy to measure.  However, as you can see, it is really just a very indirect marker of some much more  important / interesting stuff that is going on in the body, most of  which is not easy to measure without expensive gear. From the  perspective of the average (or even professional) athlete, it is simply  important to realize that you don’t want to be crossing CP with any  significant frequency or for any significant duration if you are  expecting to do your best in a triathlon, particularly a long course  triathlon.

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Juerg Feldmann

Fortiori Design LLC
Registered:
Posts: 1,530
 #2 
Got a fast response  on this one.
 Point  well taken.
 The reason  why  in cycling  wattage is  so popular is as it is an easy  to grab concept.
  Absolutely true  and we  not only  love the simplicity ,but as well the  way that it is absolute.
 I react  by 80 %  of  FTP the same  as  my neighbor  and the Tour   de France winner ? 
220 - age  for HR  is as well a great simple  concept  and  a reason why it is so popular. No  evidence nothing  and even the  "inventor is  surprised .

220 - age Hasket rule.jpg 

 Are you in  the zone   ??
 Same  for %  of VO2  max. Are all people  being able to push the same  duration by 80 %  of their VO2  max . ???
I think that this discussion  should be  over since a long time.
Nice  would be be  to use  any of this concepts  with as  many affordable bio markers  as possible to  find the individual response rather than the  mathematical  forced  response.
So use  any concept  and add some physiological  information to it. So here  how  easy it could be
(with always some open questions.)


  The key is that so long as you stay below Critical Power, your body is able to maintain a physiological steady state.  After several minutes, oxygen use levels off, and lactate concentration  levels off. In the muscles, the concentration of creatine phosphate  (PCr), ATP, inorganic phosphate and hydrogen ion (i.e. pH, or how acidic it is inside the muscle) stabilizes.  Once you go hard enough to cross Critical Power, bad stuff happens. In  other words, let’s say your CP is 240W. If you go to 250W and hold it, the result is a major metabolic upset inside the muscles . Even though the work rate is not changing, there is still a progressive increase in the amount of oxygen used, a progressive increase in lactate concentration in the blood, and a progressive decrease in ATP, PCr and pH inside the muscle. It is very cool, because you cat  actually watch a lot of this stuff happen with a specialized MRI setup.  Eventually, you reach some limiting level of these markers, fatigue, and must stop, or at the very least drop to some  much easier intensity.


 How  you add MOXY  to that ?.
  1. If  you are below  critical power  so  you have  much more  O2  delivered  than you use ,
your SmO2 will increase  and tHb  can increase depending on your  limitation ( CO  , vascularisation  and so on ) SmO2  will go up till it is  flat  as it is the  optimal O2  loading  now..

 2. If you are  in and  around the wattage of your CP  your SmO2    will be flat   and  it can drop   and  get flat again (  slow  O2 component reaction due to  time lags  of  delivery systems    and more )and tHb   can be flat  which s optimal. It  can  go up  when  a  compensator is  successful  ( CO  )  or it  can go down, when  we have  a  CO limitation.
 If you know that from testing you  have different stimuli  at CP 

 3.  If you go above  CP     you  will have a  drop in SmO2  and  a  different reaction up or  down in  tHb  depending on your limiter  and compensator.
  SmO2  will  drop  and depending on how much  above  CP  you are SmO2  will drop faster or slower.
 tHb  will drop  if your  CO  is overruled  by  muscle compression.
  tHb  can go up  if your muscle compression clearly overrules   CO  so you may start to create a  venous occlusion trend.
 Rarely will you see  an arterial occlusion as you ride  .
. tHb  as well can go up  when your CO   is still great  but your  Resp  is  the limitation so CO2  will add  to the vasodilatation and tHb  will go up. The difference between muscle  limitation  ( occlusion trend )  and  vasodiliatation increase in tHb  is  made  when you suddenly stop.  Vasodilatation trend will show an immediate   increase in tHb  due to  release of tension and still CO  higher  and CO2  high.
 In an occlusion situation   tHb  will fast drop  as it is an occlusion out flow before it  will go up.
 So  very easy to  combine  with CP  and  as CP is a physical information the add of NIRS    with physiological feedback will allow  you to  adjust on the go the  current CP  training  above or below . If you only use CP  you are not sure  as  performance  may be influenced  by physiological   situations      like heat   and so on.
 So  no brainer  for me   to combine   the two  so great   objective  physical performance  and great live  feedback on physiological reactions.
 Just needs q little bit of an open mind   from all  stuck  Gospel believers that there is no such thing like the  GOSPEL  but many great ideas we  can combine  for the benefit  of all.

Ruud_G

Development Team Member
Registered:
Posts: 279
 #3 
This is a nice discussion. In coming weeks I will post some findings on this from myself. Powermeter and Moxy data.
Juerg Feldmann

Fortiori Design LLC
Registered:
Posts: 1,530
 #4 
This will be super nice  and interesting. If you have MOXY  csv  files  with it    and you do not mind  to give them a closer look  from our side  please email it  to my  email under factquestions@hotmail.com
 Thanks in any case  as it iss always nice  to get outside  feedbacks  and data's  to compare  and to discuss. Hope you where able to add BSX  to it as well.
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