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juergfeldmann

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 #1 
We have often the  discussion and thoughts,  that physiological  reactions may not always be predictable over mathematical  calculations.
 This is  why  I like live feedbakcs  in a  daily   task  so my clients  can see   what is going on  and how  feeling and realty of  feedbakcs of  different systems  connect  with each other.

 If  I an choose between a live feedback    where I see  what is going on, whether I  overload  the  target   system or whether I compensate  with another  system I may or may not like to overload , than I always   would choose this live idea rather than looking in a  calculated  option ..
 Mr. Coddens ,a  reader  on this forum had a great  discussion in golden cheetah  and here a great respond  to his discussion. 
  
athan Townsend 
[image]
3 Nov
- show quoted text -
There are multiple reasons why W'bal may not coincide closely with 0 kJ at exhaustion.  One of those is of course CP + W' estimation error.  In general, when the effort duration is longer than about 60-90s, errors in W'bal at exhaustion have more to do with the CP estimate.  When the effort is short, then error in W' makes a bigger difference (this should be pretty simple to understand purely from a mathematical perspective).
 
If CP is underestimated, then what tends to happen is that W'bal drops negative during HIIT because you're telling the model that you are less fit than what you really are ie: you can actually produce more power and expend more energy than what the model "thinks".  Converse applys for overestimation of CP.  So for example, it might be that your CP is slightly overestimated in this case.
 
Another factor is that performance is always variable anyway. So maybe you're a little bit more fatigued on the day you do some maximal effort intermittent task as compared to the day or days when you did efforts to model CP.
 
Lastly, a problem which is common to all scenarios is that neither the integral model or the differential model is perfect. At present the models are a bit too simplistic and so they're not robust enough over a braod range of situations ranging from say short shart crit race style efforts on one end of the spectrum to longer sustained efforts but with long recovery between efforts (eg: a road race circuit with one big hill.  Everyone recovers on the flat section in between the hill, then pushes hard on the hill each lap which creates the selection).
 
 Now   for all  readers  using physiological  intensity so  working in the  OXY intensity, but overloading a  target systems like  cardiac  or respiration or   coordination or what ever like  they will have  an easy  way of understanding this  You may bike with 50 watts  and you  may  desaturate lower  than  when going 400  watts . W  bal  will have a very different feedbag  . Why  ?
 
 
bobbyjobling

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 #2 
Juerg, do you when using a NIRS look at absolute values or do you just use THb & SMO2 trend? So for example if one day during the calibration period (no cycling for 3-5 minutes) your subject SmO2 reads 10% higher or the desaturation is at a different level for the same load to the previous day/week do you worry? Or do you specifically do a specific assessment depending on what you are going to physiologically target that day.

The reason for my question is that I get very wide range of results on my VL. I just need to move my moxy by 7mm towards my RF of towards my hip and I have completely different results on 5-1-5 assessment. One Smo2 desaturates down to 10% and the other only down to 20%. How critical is the placement for the sensor?
CraigMahony

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 #3 
I am also interested in the answer to Bobby's question.
juergfeldmann

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 #4 
Bobby  a very great  questions  and I think as well very important to  to see limitation in SmO2  use.
 Here what I do.
1. In athletes  or patients  I know I will follow through over  a long time  I  keep track on SmO2 trends  to see, whether there is  pattern in values.
So  I  do some specific  respiratory  overload  works  and than  reassess as we  do  with HRV  or Resting HR  or RRA  and so on .
This gives me a physiological finger print on SmO2 trends when I overload  the respiration.
 Now you do the same with cardiac overload.
You do the same with coordination overload.
You do the  same  with  strength options like inter  or intramuscular  coordination. Result  : You have  an individual finger print  on SmO2  reactions ( Trend ) but over time  you as well see a certain trend , that  after   certain loads  you  can see desaturation  nicely  or  you have a problem  to desaturate.
 You look at sebo2000 and his regular assessment. Crucial   placing  at the same spot so use  anatomical markers  for placements.
 Now  here a  picture  I showed before.
 The   study was to look at  changes in SmO2   absolute  values    and trends. The study  was actually designed  to show , that when  going in altitude  or hypoxic the  desaturation trend  is  similar in Vastus  lateralis in different section but the absolute values  are different.

I had  this  lie  many questions out  there for classical   users  and in this case  for VO2  users. The question was :
 if  I go in   altitude  what is changing ., Is VO2 max the  same ,   less or more  at altitude.
 If  it is less  what  would we see with   SmO2  or  O2Hb  levels   less  desaturation or more. What  is the trend if  VO2  max is the  same  in SmO2  and what is  when it is higher in SmO2. Do  they  run together , Higher  VO2 max   lower ,than   drop in SO2    and so on. So here  once more more the picture  with the three placements.

vastus lateralis  4 NIRS.jpg 


Now  I  think Bobby  asked  the  question in connection with W  bal.
 W bal as a  mathematic  great idea of  fatigue  shows  actual numbers. The may go negative  or  not  down  to zero  do  to  different intake of wattage numbers.
So nice  would it be if  we had an absolute  SmO2  number.
 . We  don't  have this  (  if we  do not have a set of  data collections ),but we have a live feed  trend  , when we  know the  O2  utilization reaches  at  the specific workout  you  do a specific   low  level. Simple experiment.
Use  your biceps  and do a biceps  curl.
 Gleno humeral joint  at  zero neutral position. )Don't look at  the screen and stop  when you  feel or see with SEMG  that you start compensating  with  for example brachioradialis or long biceps  head  or  front delta  and so on or body  motion.
. Do 3 - 5  reps  with it looking at the live feed.. Than  look at trend in tHb  and SmO2. Now  do the same  and  decide on the SmO2 trend or tHb trend, depending whether  your goal is  utilization trend or   blood volume / flow trends  , when you stop and combine this with your body feeling. look what you see and you will be surprised on how your feeling is a great  guide  after a  few sessions.

bobbyjobling

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 #5 
Ok (specificaly for cycling) Is it possible then to create a new calibration procedure to compensate for variation in moxy placement on VL or RF? And to aid live race feedback.
It would be nice to do a quick test to find our live maximum homeostasis.
When I get back from holiday I will try some test.


juergfeldmann

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 #6 
I am sure  certainly in cycling  we will soon see some mathematics  wizzards  to  find a  " magic "  formula. There is  an advanced  group in  |Switzerland  who  works on a  software  with algorithm  for  ideas  like that. They  have a  Massenet  software  as well a   live  workout feedback software in the works.
  We use in real live  actual real feedbakcs  and  worry less n  SmO2  numbers. A  what some may call " homeostasis ' is where we ave s many biomarkers  as stable as possible over a recent amount of  time  for the activity  we do.
 So  stable HR  , stable  SmO2  , stable  tHb, stable lactate  for  people  who  use that, stable RF  stable TV  so stable VE  for people using VO2  equipment. Relative  stable SEMG for   this group,  stable  or relative stable  performance  but least  important.
Again  there is some inconsistency  from placement  and   possibly many more  factors like we have  with many other tools    so that's  why  again if  I have  people  using it a few  times   I only  look at curretn trends. In case  I  have a   consulting contract over    for sure a year but in many cases   many years  we  start to see trends   and collect this data  veer   regular  and have a clear patient  with numbers  who are getting close  to be predictable.  So  we have 
  cases, where we have years  of  data and can actually have a  nice  but never perfect  idea   when we  start a workout  based on the calibration  numbers.
juergfeldmann

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 #7 
Smile , Still looking  or VO2  equipment users  for some answer on  VO2  max trends  and SmO2  relation.  Still looking   for  FTP users  on  a live feedback  2  x  in a row  from a  FTP  assessment   with live NIRS feedback.  Still looking  for  golden cheetah users  and W  bal and live SmO2  feedback  when they do a   low  wattage  workout  to " fatigue "  for example coordination and  a high wattage  workout. And  if  we are already looking , many open lactate  questions  .
 I love to  give possible ideas  ( some times no answers  but I  would love as well to have some  additional  answers  to many questions  [wink]
Oleksiy

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 #8 
myscreen.png May be you find this relevant to the discussion. Here is first 40 min of my race data with Moxy (right RF). You see I "exploded" at ~25 min. 
juergfeldmann

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 #9 
Really great  and lets look  at the  2 interesting results  of  NIRS  , versus  w  bal..
 Now  first   somebody  form the   Wbal  and power community   please  explain our readers  in short s9mple words what W  bal  suppose to tell us.
 A  high  W  bal means =

a lower W  bal means. ? =  Example  :  at the start we have  WE  bal  +-  35 
at the end of  the   load we have it at  30 +-
by  25 min +- W  bal starts  to climb  again.
 As  w bal is   an indication of ?????  that would mean by 25 min  the athlete actually  did ??????

Now  need help.  If  you can sent me the   NIRS information as a  csv  file  that  woudl help  even more  to show  some NIRS feedback of  this case.
Thanks  for the great  information.
Oleksiy

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 #10 

Sure, please have a look in the attach. 

Also on the topic, there is a new proposed MPA (Maximum Power Available) metric from the Xert guys: http://new.baronbiosys.com/?p=89


And this is the end of the race (cramps started at ~1:50, the rest was on the pedals)
Screen Shot 2016-11-25 at 7.07.47 PM.png 

 
Attached Files
csv 2016_11_19_11_49_13.csv (123.53 KB, 9 views)

juergfeldmann

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 #11 
Got  on  email.  why csv  . 
The graphs  on  here look great but  from an interpretation point of view  are  too   big and too generic . The csv  file  will  possible ( not always ) help us  to see what happens  wit   25 +-  min  physiological reaction. Look at  W  bal .
 remember the question.  and the answer we look  for.
 What is  W  bal used  for.
 So  if  it drops  that means ???
 if it goes up  that means ???
 

juergfeldmann

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 #12 
As a  coach   you  can look at three main areas  from a physiological point of  view

1. Start  section look at  HR  and SmO2  reaction   and at  load.
What  did  happens  here   ?.

2. Section around  +-  2 min. Look the physiological reaction there. What started  to limit performance  and  " killed " the rest of  the  load.

3.  Always great to look at the end  of  a  load. What  do we see there. ?

smo2  thb  all three circles.jpg

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