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Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
I like to  give here a reply on a very common question we are getting over the last few month.
  This may help many readers  to have some better ideas on what we    work towards.

Roger here some feedback to your interesting    email


“Hello, I am a strength coach working with flat-water kayakers. How can I assess, program, and monitor athletes using Moxy? Does it help me figure out lactate threshold? Do I program training's around heart rate or cadence that correspond with oxygenation at certain levels during an assessment? Cheers XYZi”


1. Water sports like rowing , kayaking  but as well swimming   may benefit  much more    by using NIRS/MOXY , than  many coaches for the moment   do not recognize.

 Why?  This are all sports (certainly rowing and Kayaking) where at the start you have to go hard to get the boats into surf    position to reduce water drag to a minimum. On the other side you have options (stroke rate versus stroke length and more, pretty much like in cycling with RPM and so on. MOXY will help to see, what is better at the moment and how I can change into what I may like to have. In a  4  men rowing  boat  we  may have  one member    who  will have a utilization problems  in a 40 stroke rate  due to an  occlusion build up  where  another member  may have a utilization problem due to   lower mitochondria density and vascularisation. So   both need a very different training intervention. In the past only an experience coach may have picked that up ( IF ).

 So here some short starter answers to the questions.


1. How can I assess

 In a race situation first and foremost. You like to see, what limits the race performance and then can plan from there.

 Once you have the limitation from the race performance (utilization /’ delivery) you make   the three options we use for testing. TRIP as a Trip though TIP (training intensity profile) to find intensities for improvement of   vasuclarisation. Mitochondria density, cardiac limitation or respiratory limitations or technical coordination intensities.

Than you make a RIP   Recovery intensity profile   to find out duration of intervals, recovery times between loads and numbers of reps in a full workout. This as well is on the water and or on a kayaking erg.

 Last but not least you make a  SIP ( strength intensity profile  to design the load  and  the duration as well as the reps  for what you like to achieve  with the sport specific  strength.


2. program, and monitor athletes

 The program is  what you are always doing   , so the  change is only , that for the assessments as  you now know the limitation  and the  compensation  and you can now specifically use  your training ideas  to   address this  situation. Then you go and retest and see, whether the goal you had set is reached with what you planned   in your workouts.

 The monitoring part is easy. In the gym big screen and live feedback during workouts.

 On the water. The athletes  over  a Garmin watch  FR 70   and the coach over a wasp systems  from the boat  who follows or  in a  rowing pool with roads on the side  from a car over the PC  and walkie talkie  connection to the boat to correct and see live as you train.


3. Does it help me figure out lactate threshold?

 Dangerous question for us to answer.

 Some believe   they can use NIRS to   look for a lactate threshold or anaerobic threshold.

 We have some open doubts about that because what theory is your idea of lactate threshold or anaerobic threshold.

. What muscles in the sport  like this  will contribute how much  to what kind of a lactate  concentration and even if you have lactate in the system  is that really that  bad  and what does it means other , that somewhere in the body  you  creates  a  certain amount of a metabolic  reaction, where  lactate was  as well involved  to either buffer H + or  was shuttled  to be used on an other place  or  was  simply too much in one area  so  got moved  out over MCT1  and  moved in over MCT4  in another area.

 We  do not use lactate as  any  kind of a tool  for any  intensity control nor  any other   info  than  looking from a nutritional point of view  pre  race or  pre training whether the   glycogen storage may be  refueled or  not.  ANAEROBIC THRESHOLD - A RELATIVELY USELESS CONCEPT FOR COACHING

Billat, L. V. (1996). Use of blood lactate measurements for prediction of exercise performance and for control of training: Recommendations for long-distance running. Sports Medicine, 22, 157-175.


This article contains a very concise summary of the concept of anaerobic threshold and how it is depicted in the literature. The implications of each individual statement are particularly important given the pre-occupation of many coaches with this concept. The major points of the article are discussed below. Further features are introduced in the "Implications" section.

The concept of anaerobic threshold itself is not universally consistent. Long dynamic exercise that is predominantly aerobic ranges between two extremes of physiological dynamics resulting in very different blood lactate levels.

  • At the lowest level, an exercise can be sustained for a very long time. After 2-5 min a state of overall oxidative energy supply is established where lactate production is balanced by lactate elimination at a low level. Fat (lipid) metabolism is the primary source of fuel. Exercise limits are mainly associated with eventual increases in internal temperature. Potential dehydration can be prevented by supplementation of water and substrate (carbohydrate and electrolytes) during performance. (p. 158)
  • At the highest extreme, the workload requires an additional formation and accumulation of lactate  to maintain power output. Exhaustion results through the disturbance of the internal biochemical environment of the working muscles and whole body caused by a high or maximal acidosis. Generally, accumulation of  H + limits performance to periods from 30 sec to 15 min. For example, the average time to exhaustion at the minimal velocity which elicits VO2max is 6:30 and is not correlated with the blood lactate level developed during the task. (p. 159)

Between these two extremes are transition stages, several of which are labelled similarly as "anaerobic threshold" or "lactate threshold." Thus, the same label is used for different concepts and their assessment protocols that lead to different values and training implications. Billat displays the various implications of this confusing situation. According to a variety of "authorities," changes in blood lactate accumulation are termed and defined differently as well as being associated with different levels and characteristics of accumulated lactate. H+ They are also differentiated by the protocols used to measure them. Some examples are listed below.








4. Do I program training around heart rate or cadence that. We would program around MOXY info as this is real live feedback so tHb and SmO2 trend information. RPE and HR as well as lactate are not optimal ways to find   proper intensities for sport.


Eur J Appl Physiol. 2002 Jun;87(2):159-66. Epub 2002 Apr 18.

Reproducibility of the blood lactate threshold, 4 mmol.l(-1) marker, heart rate and ratings of perceived exertion during incremental treadmill exercise in humans.

Grant S1, McMillan K, Newell J, Wood L, Keatley S, Simpson D, Leslie K, Fairlie-Clark S.

Author information

  • 1Institute of Biomedical and Life Sciences, University of Glasgow, 64 Oakfield Avenue, G12 8LT, UK. S.


The aim of this study was to investigate the reproducibility of blood lactate measurements, heart rate (HR) and ratings of perceived exertion (RPE) during treadmill exercise at speeds corresponding to the lactate threshold ( v(Th,la)-) and a fixed blood lactate concentration of 4 mmol.l(-1)( v(la)-(,4)). Possible differences in reproducibility related to fitness levels were also investigated. A group of 20 men [mean (SD)] [age 20.5 (1.4) years] and 16 women [age 21.2 (0.9) years] took part in the study. The subjects performed two identical incremental exercise tests consisting of at least six 4 min stages. Blood lactate concentrations, HR and RPE were recorded at the end of each stage. Limits of agreement (LoA), correlation coefficients and 95% confidence intervals for the mean difference between tests were employed to investigate the level of agreement and reproducibility of blood lactate concentration, HR and RPE. For the group as a whole, the sample correlation coefficient for speed at v(Th,la)- was r=0.88, and was r=0.92 for the speed at v(la)-(,4). At v(Th,la) -, the correlation coefficients for the moderately fit and unfit were r=0.94 and r=0.36, respectively, and at v(la)-(,4) r=0.93 and r=0.68, respectively. The LoA for the moderately fit group indicated that a change of 1.62 km.h(-1) in v(Th,la)- would be necessary to be considered a change in training status. For HR and RPE, relationships between the tests were generally poor. The LoA suggested that changes in scores must be unacceptably large. These findings cast doubt on the sensitivity of testing for change of blood lactate concentration, HR and RPE in this population.


Reproducibility of aerobic and anaerobic thresholds in 20-50 year old men.

Aunola S, Rusko H.


The reproducibility of the aerobic (AerT) and the anaerobic (AnT) threshold was studied in 33 men aged 20-50 years. They completed two maximal exercise tests on a bicycle ergometer. The thresholds, as VO2 (1 X min-1), were determined visually by two investigators using both the blood lactate and the respiratory indices. The respiratory variables were measured with a computerized breath-by-breath method; samples of venous blood were drawn every 2nd min and analysed enzymatically for lactate. The reproducibility of the AerT (r = 0.94) and of the AnT (r = 0.96) were equally good. The AnT can be determined either from blood lactate concentrations (AnTLa) or from ventilatory and gas exchange response (AnTr) during a 2-min incremental exercise test. They both also showed similar reproducibility: r = 0.93 for the AnTLa and r = 0.95 for the AnTr. The work rate and the measured physiological variables at the AerT and AnT, except for the blood lactacte concentration, were very reproducible. Age did not affect the reproducibility of the thresholds. The poor reproducibility of blood lactate concentration of the AnT confirmed our previous opinion that the fixed blood lactate levels of 2 and 4 mmol X 1(-1) are poor indicators of AerT and AnT.

  And here another study  which is really a summary  for many studies  done in teh late  1980 in Germany .


© 2013 Published by Elsevier Ltd on behalf of Sports Medicine Australia Reproducibility of lactate markers during 4 and 8 min stage incremental running: A pilot study James P. Gavin, Mark E.T. Willems, Stephen D. Myers Department of Sport and Exercise Sciences, University of Chichester, UK



This study examined the reproducibility of speed corresponding to specific lactate markers during incremental treadmill running of normal and prolonged stage durations. Design: Nineteen healthy participants (14 male, 5 female) performed repeated, incremental treadmill running trials of 4 and 8 min stages on separate days to examine the test–retest reproducibility of speed at lactate markers. Two trials were completed for each duration in a randomised order. Methods: Fingertip blood samples drawn upon stage completion were analysed for plasma lactate, the used to determine running speed at: 2.0, 3.5, and 4.0 mmol l1fixed blood lactate accumulations (FBLA),a 1 mmol l1rise from baseline, and the markers: the deviation maximum (Dmax), the Dmaxof the second  curve derivative (D2Lmax), the lactate threshold (LT) and log–log LT.Results: The 2.0 mmol l1FBLA reported the lowest mean bias between 4 min trials (0.06 km h1), with the narrowest limits of agreement (LoA) (1.78 to 1.66 km h1). The Dmaxhad the second lowest bias(0.14 km h1), D2Lmaxthe second narrowest LoA (1.93 to 2.90 km h1). For 8 min stages, the 1 mmol l1rise demonstrated, low mean bias (0.13 km h1) and narrowest LoA (1.22 to 0.97 km h1) between trials


 This preliminary report suggests the reproducibility of running speed at lactate summary markers is influenced by stage duration for incremental treadmill running. Varied marker reproducibility between 4 and 8 min stages indicates different blood lactate response, and therefore workload calculation, according to stage length. Consideration of marker construct is recommended.

  Hope this helps a little bit.


Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
Here a great feedback on the GC  website  forum  by Ross Holman
Fantastic work (as usual) on supporting MOXY in GC.
I have read just about every line about MOXY including the information in their forum posts and I get that it is a fundamentally different paradigm to existing training approaches. However, I have yet to make the commitment to buy one because of the lack of clarity over exactly how to interpret the data it produces and how to apply that into a training regime that produces measurable improvements.
So having done a reasonable number of rides with MOXY my question to you (and any other MOXY early adopters) is have you been able to interpret the data produced in any meaningful way, particularly related to your power, to guide your training. For example can you tell when you are recovered between intervals, can you use it to judge intensity and duration for intervals, has it helped you to identify MLSS?

 The  key pont  for me  it seems is this section here :

  clarity over exactly how to interpret the data it produces and how to apply that into a training regime that produces measurable improvements.

Using NIRS   ( portamon  first  and now combinations  and MOXY a lot )  since many years we have a  good but ,as so often ,not complete understanding on data interpretation.
 I asked Mark  to sent me some of his workouts  like a Wingate  test  he may do  or any interval workout  he may like or  any  other test ideas like a VO2  test. Based in this csv  moxy file information with or without  HR  and with or without power feedback ,  we can show you what  or where we  can read information from tHb  and SmO2 and where we have  some open questions.
 We  can as well use   any VO2  information  or any lactate ( MLASS ) data   with MOXY to show you where the there are  sometimes conflicts  from classical ideas  versus a direct feedback  from any NIRS  equipment.
There are many  interesting studies now  done as well by looking at  Brain O2  situations during  workouts  to see, how the potential   theory of  central control stands up  against classical  peripheral    limitations.
 In short . We   make daily   many interpretation  world wide  for athletes  and coaches  over  a Swiss company  and  the information   is  sent to the coach  and or athlete with the information on what is the limitation for now  and how is he compensating in a hard workout or  race.
 . Than it is up to the coach  to    use  his  training ideas  and workout  ideas  to see, whether what he is doing really is changing the limiter to a  good   or better level , or whether the workout has not influenced any of the   problems  at hand.

Here aa a very  short insight  view in the changes  due to technology   from the   " classical " model on  ATP CrP  glucose  and  somehwere down the road   O2 use  to some  interesting new  informations thanks to   better   technology. This is a  short internal excert  for a presentation we have in 2  weeks.

Robert G. Shulman

Department of Diagnostic Radiology, Yale University School of Medicine, MR Research Center, New Haven, CT

SHULMAN, R.G. Glycogen turnover forms lactate during exercise. Exerc. Sport Sci. Rev., Vol. 33, No. 4, pp. 157–162, 2005


We suggest that glycogenolytic ATP production supplies the energy for millisecond bursts. This hypothesis implies that _1 _mol·g_1 tissue of

glycogen subunits is consumed during each contraction to

refill the ATP and PCr pools. Because basal glycogen concentrations

of _70 _mol·g_1 tissue are not depleted even after several dozen contractions, resynthesis of glycogen must occur between twitches.

Without the millisecond time pressure of contractions, the ATP required for this resynthesis can be achieved via somewhat slower oxidative means.

Although oxidation cannot supply ATP in milliseconds, it could resynthesize glycogen in the _1-s interval between even rapid contractions. Measured rates of oxygen consumption vary, seemingly dependent on the measurement method.

None of the reported values reaches the rate of 1 _mol·g_1 tissue per twitch, but the fastest values measured do reach several _mol·g_1 tissue per second. Hence, it is possible that the glycogen pools, which are decreased to refill PCr and ATP in milliseconds, are replenished by the energy supplied oxidatively in the longer period, no shorter than _1 s, between contractions.


Evidence That Glycogen Rather Than PCr Generates ATP during Contraction


The conventional view of short-term muscle energetics is that PCr supplies almost all of the energy needed for a sustained burst of contractions lasting less than 10 s, after which it is replaced by glycogenolysis.

This view is not supported by experiments. In a recent review, Greenhaff and

Timmons (5) report, “It is now accepted, however, that PCr hydrolysis and lactate production do not occur in isolation, and that both are initiated rather rapidly at the onset of contraction.”

Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
I just got an email from a rowing coach  from Banyolas ( Spain )  a  wonderful lake and rowing paradise in the    province of Catalonia ( Spain) Here the  question he  had   triggered  by this part of  one  of the explanations : 
In a  4  men rowing  boat  we  may have  one member    who  will have a utilization problems  in a 40 stroke rate  due to an  occlusion build up  where  another member  may have a utilization problem due to   lower mitochondria density and vascularisation.
 His  question was :  what can cause a  occlusions in rowing  and where ?
 a)  you have to options of occlusion, depending on the    muscular compression pressure (  often dependent on the % of  force  used   as a % of the maximal contraction force) . The  first    reaction, once the compression increases  too much is the  development of  a venous occlusion. This means  , that the compression is so strong , that you start to reduce  or  cut off the outflow  ( venous blood vessels )  of blood. In sport many describe the feeling as  muscle pump ( rock  climbing  or  motocross as a  forearm pump. So blood still moves into the muscle  ( arterial inflow still okay ) but little or nothing can go out).
 Now there a a few reason who can create this reactions. Here 2 common once,
a)  muscle strenght weakness or in other term the problem , that the effort achieved  reaches  50 +-  %  of the maximal contraction and you start  to close blood vessels.
 b) respiratory  limitation  due to metaboreflex. In rowing or cycling or  cross country skiing , but as well in sport  lie ice hockey more common than often accepted. The metaboreflex is a  reaction where as the body will create a vasoconstriction  to " protect the basic O2  needs  for the respiratory system ( muscle ) Now you have a  high compression force  and towards the end of the race you  have the problem of a metaboreflex kicking in  and you add to the muscular compression now a  additional systemic vasoconstriction  and you can reach a venous  and or an arterial occlusion..
 With NIRS/MOXY  and  a specific  assessment  you can differentiate this 2 occlusion  so you have the answer  and now can either work on the muscular reason or  on the respiratory reason of the occlusion.
 I will sent you in an email examples  for your rowers   on how you differentiate  between muscular triggered occlusion  and respiratory triggered occlusion. So if you sent me a race or  race like training   csv  from a MOXY assessment than we can look what the different rowers  have as a limiter in case they  will create an occlusion. We showed on this forum a few  venous  occlusions  from rowers a  while back and I will  try to find them  again in my mess. Thanks  for the  email from beautiful Spain.  and say hello to Banyolas. Have goo memory from this  area as I spent  15 years  there  every year 2 - 3 month where we  where running cycling camps  and Banyolas  and a  bike around the lake  was one of  our   nice  day tours  from Giverola  to  Girona  and over Banyolas to San Feliu back to Tossa de Mare.
Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
Here a nice   answer  from the GC  forum.
Couple of things;
(1) too soon to say about utility, I've collected data but haven't performed any specific tests so its a bit random. My goal so far has been to get data in. Next is thinking about what to do with it.
(2) I have recorded it on the Moxy but no real time display as I ride. But again, with indoor riding it may well prove very useful when riding tests and intervals as you indicate; to temper effort or guide recovery between bouts.

 There is one option we offer  since many years : sharing data and asking each other  critical but fair questions. The same questions e   ask about limitation of the MOXY  have to be applied  by asking   this   for  classical ideas like FTP, MLSS, VO2 max , LT , ANT, VT  and so on.
We use  MOXY  for  useful when riding tests and intervals as you indicate; to temper effort or guide recovery between bouts.

 We use this  in High schools  for soccer teams , ice hockey teams , strength workouts and more. For downhill skiing   to know  , when  they are ready for the next run in training,  for  cyclist, when they  launch an attack  how   long they can go before they  kill the  systemic  situation  or  how fast they recover  to  get the next one going, for patients in rehabilitation on how many sets  and how  hard the quality of the contractions. Do I like a  blood flow still or  do  I like toe  try a   occlusion workout  and so on. For rehab  situation to see, whether an athlete is ready to go to race intensity workout  s  or event back to a race  or people back to certain work  after  operations. here one example of a report    after ACL  surgery. acl.jpg 
 Now there are different ways  to learn.

" That makes a difference from claiming to have pioneered it 10 years ago, I suppose.
Lets collect data and learn from it whilst others talk about it."
  it is like
  rw 1.jpg 

Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
Here  the second  part of our   readings here  from the same coach asking some great questions  and helping us  to understand  where the   big questions  are  and how to address  them  to benefit  Romfrom NIRS/ MOXY equipment.

Thanks for getting this to me! Great information. This sounds like a great way to assess athletes. It makes more sense to use a direct measure to assess an athlete than to use that measure to calculate an indirect measure like lactate to program an athlete’s training, especially if a measure like lactate may not be the greatest indicator of threshold. The questions I still have are:

During your testing protocol, you use SIP RIP and TIPs to determine threshold right?

In short NO, we are not looking for any threshold in any of the assessment. We are looking for either training intensity to work on the elimination or progress of your limiting system , or we use the assessment to design the length of a workout load in an interval workout as well as the length of the recovery in between loads and last but not least look on the MOXY feedback how many sets each of your athletes can do. So instead of design 5 sets (because we have 5 fingers) 60 sex load because it is one loop on an old clock and 1 min rest as it is again easy to watch you may have for each athlete a very individual load given by the SmO2 trend and or tHb reaction for load duration rest period and amount of sets. So in Short. the TIP ) training intensity profile has the job to find the limitation for your O2 delivery or utilization. For example does the athlete has a respiratory limitation as a limitation of actual respiratory muscle weakness? This than leads to a problem in high intensity , where the accumulation of CO2 due to reduced VE creates a right shift of the O2 Diss curve so we will see a drop in SmO2 but as well as problem with O2 loading in the lungs ( drop of SpO2 ) and therefore as well as change in tHb (CO2 increases vasodilatation in the systemic circulation but creates a vasoconstriction in the pulmonary circulation, which than start to get more work for the right cardiac ventricle and so on. So we know what the weak link is and then we will find intensity where we only push this weak link or another intensity we push the weak link and go harder so other system will have to try to compensate and so on. In the classical idea we found or we at least were hoping to have found a critical point named threshold. Now what, now we used a calculator to get % of this even though we know , that the same speed or HR may be very different in energy demand the next day. So no no threshold but live feedback daily on where your body reacts to day for a given planned load and whether we have to adjust the load for the same physiological stimulus we have planned. It is after all not the performance ( speed or wattage ) who decides what physiological needs you will have to come up with it is the physiological ability in a given workout who decides the performance you can achieve.

Are you are still looking for “anaerobic” and “aerobic” thresholds, just based on NIRS measurements instead of lactate?

No , see above. There are numerous interesting new studies with new technology, which show that there is no such thing like anaerobe. Once you use a moxy you will be surprised how fast So2 drops but even more you will be surprised when you look SmO2 development during the load that you can predict, when your athlete will start to suffer or you can see and feel it on yourself. This opens the hard question. Is the energy model from Howald( which was actually my teacher at t he university in Bern ) with the idea of ATP first followed by Cr.P than anaerobic glucose and then somewhere later O2 and glucose really not up to date anymore. The latest updated research shows a very different picture with O2 involved in ATP level maintenance already in the 1 sec time frame upon start of a load. If you are interested I can sent you some of this studies, which simply did not made it yet into the mainstream of exercise physiological books and coaching seminars.

Are there protocols in place already for specific sports testing like kayak and resistance training?

Yes we have more or less protocols for any sport for TIP as well as sport specific protocols for RIP and SIP. You can do it on the water if you have a power meter or speed sensor or on a kayaking erg as well. The SIP ( strength intensity profile can be done on any specific strength training you may like ( squatting, Chin ups , or single motions like leg press or sitting rowing or triceps whatever.

Thanks again for all of the info.




Development Team Member
Posts: 15
Hi Juerg,

Thank you, I am trying to get some basics on this, so I can add features or metrics;

1. We can use NIRS data to ensure efforts are hard enough
    - tHB will rise, SmO2 will fall as we work

Question: How do we know how high to go? Is there bandings we can use?

2. We can use NIRS data to ensure we are recovered before repeating a bout
    - tHb will fall, SmO2 will ride as we rest

Question: How to we know when it is time to go? Should be have a resting baseline to refer to?

3. We can track rise/recovery of SmO2/tHb to assess changed ?

Question: Will the time period change over time (?)

4. Tracking O2 delivery

Are there some KPIs / Metrics we can use to track trends over many weeks/months/season ?


Juerg Feldmann

Fortiori Design LLC
Posts: 1,530

Interesting points Mark
but I need more help. We  tried  and still try  challenging this idea  since  many years,  here a short  overview  I exchanged this very early on with ROGER  as we  where looking  for ideas like this when we used Portamon.

SmO2 trends.jpg 

 These are  options  we see in  reactions of   activities.

Now   reading  through your posts,  we have some open questions which I will outline below.
  Most help full would be for many readers, if you  sent us a  FTP test you  do , or  any reader  who has a  MOXY ( better  2) ,  including the MOXY data's  you create  from there and, if possible on an  involved  and  a non involved  muscle.

Than  make a  20 min " replacement FTP  "and calculate the FTP wattage, but as well  use MOXY  so we can see the  possible or not possible differences between a  physiological  effort over  20 min and the physiological reaction over the 60 min and than can compare the wattage  and physiological  trend  from the 20 min assessment  and the  calculated wattage  for  calculated FTP  over the 60  min.

 This  would be a  fun  discussion  between physiological feedback and physical performance calculations. as well as  what can we read out of  wattage   over a  60 min  test and what can we read  out    from MOXY over the same  duration  and how  would we use  the wattage numbers  to design a  workout  versus a moxy info to design  a workout.

  Based on  all of this  information we  can get a better idea on what you mean with " effort is hard  enough "This may help us  forward  with your ideas of metrics for training  with SmO2  and tHb .

 So here some thoughts  to your points   above.

We can use NIRS data to ensure efforts are hard enough
- tHB will rise, SmO2 will fall as we work

When using  physiological information  from MOXY we  have  less a question of  "hard  enough effort"  as  much more of  what delivery  and utilization challenges  do  we  like to create .  The  fundamental differences  are, that we target a physiological  reaction  and than look  whit  what  intensity ( performance ) we  can achieve this the best.

 Example :
 we like to train the right ventricle  so we  have to create a  situation, where  we  have  a  high tHb  level ( preload ) and create a  low  SmO2  level  (  High  pulmonary  resistance)with hypercapnia.
 So we  would have  an increase in tHb    and a  drop in SmO2.  Is this effort  hard. Yes  subjectively it  will be very  hard.
 Is it  objectively   hard  when looking  at    for example %  of FTP . No , as we  may be  able to achieve  this  by a load of  50 %  of FTP  so very low  load    from a performance level but very high  intensity  from  a physiological point of  view.

I could go  harder, much harder  to achieve the suggested tHb up  and SmO2  down , but than the physiological reactions  and outcome will be very different.

Why ?  what can create a tHb increase  / remember the two  main options  we discussed before.
What can  create a  drop in SmO2 ? again 2 main options.  ???

 So  here an example and describe  what  actually happens during this   below  workout.
 In this case  we   kept  the SmO2  stable  to get rid  of  this  options. 
 The data are courtesy  of the  top cycling center  and training center for cycling in South Africa.

 mark workout thb smo2.jpg 

 Back to the second  point :

We can use NIRS data to ensure we are recovered before repeating a bout
- tHb will fall, SmO2 will ride as we rest

Same problem here.  What did you created, that you see a drop in tHb.
 In strenght  sports  like  sets  of lifting or  specific  intervals of   sports  can create a  situation , where we see a  drop in tHB  . In most   or in many cases  when we  stop an endurance sport   intensity we  will have initially  an increase in tHb  not a  drop. Why ?
 SmO2  can have different reactions  we discussed in many  5/1/5  cases.
 -  it  may not immediately  increase    ??
 - it may increase back to  base line after   " warm " up .
 - it may over shoot  from base line.
  The question is , what  do I like to achieve  with the rest period and if I choose  
a ) incomplete  recovery 
b)  complete recovery
 c)  overload highest point 
 d)   wait till overload  moves back to base line.  
and than do we know what is the outcome of any of this versions.
 What of this options  is the optimal recovery  strategies to achieve  what kind of a goal.? This is   another  internal study  we just started  with our high school  group  in town.
 Will keep you updated as we  go along .

 Summary : I look forward  to the data collection  and than we  may be able to  create a  great idea  all together  form  the point of  cyclist on  potential " metrics"   of SmO2  and tHb.

Juerg Feldmann

Fortiori Design LLC
Posts: 1,530

Now here  to the last part of his questions.
 Yes  we  track recovery at the same training unit  but as well  recovery over time.  We use this as   mentioned d in ice hockey  and other sport's, where this is  an important part of  the overall performance during a  game, but as well for training  ideas.
  Here first an example of a  recovery tracking  during an interval.
First is  an example of 2  athletes doing the same workout  of squatting. Just look the  difference in SmO2  reactions  and  " recovery "

compa J and D.jpg

 You can see changes in SmO2 

 recovery  in the same set  and  the individual reaction.
  Now  next up is a NHL  player where  Brian tracked recovery time  as well as utilization changes  of the  period of a  summer conditioning phase.

MR  smo2 compar  legs.jpg 
 We  than  move this information in some metrics for workouts  in a team , but as well to track  changes  due to different ideas of  recovery and loading strategies.
 So it will be great to have  more people  creating some metrics from their point of view.

Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
Here another common question:
 Do other  people besides  you guys believe, that there is a connection between  respiration and  muscle deoxygenation in working muscles ?

Answer :

Related trends in locomotor and respiratory muscle oxygenation during exercise.

Legrand R1, Marles A, Prieur F, Lazzari S, Blondel N, Mucci P.

Author information

  • 1Laboratory of Human Movement Studies, Faculty of Sports Sciences and Physical Education, Lille University, Lille, France.



We investigated the potential effect of respiratory muscle work on leg muscle oxygenation without artificial intervention in non-endurance-trained young subjects and searched for the range of intensity when this effect could occur.


We simultaneously monitored accessory respiratory and leg muscle oxygenation patterns with near-infrared spectroscopy (NIRS) in 15 healthy young men performing maximal incremental exercise on a cycle ergometer. Pulmonary gas exchange was measured. The respiratory compensation point (RCP) was determined. Oxygenation (RMO2) and blood volume (RMBV) of the serratus anterior (accessory respiratory muscle) and of the vastus lateralis (LegO2 and LegBV) were monitored with NIRS. The breakdown point of accessory respiratory muscle oxygenation (BPRMO2) and the accelerated (BP1LegO2) and attenuated fall (BP2LegO2) in leg muscle oxygenation were detected.


BPRMO2 occurred at approximately 85% .VO2max and was related to RCP (r = 0.88, P < 0.001). BP2LegO2 appeared at approximately 83% .VO2max and was related to RCP (r = 0.57, P < 0.05) and with BPRMO2 (r = 0.64, P = 0.01). From BP2LegO2 to maximal exercise, LegBV was significantly reduced (P < 0.05).


In active subjects exercising at heavy exercise intensities, we observed that the appearance of the accelerated drop in accessory respiratory muscle oxygenation-associated with high ventilatory level-was related with the attenuated fall in leg muscle oxygenation detected with near-infrared spectroscopy. This suggests that the high oxygen requirement of respiratory muscle leads to limited oxygen use by locomotor muscles as demonstrated in endurance-trained subjects. The phenomenon observed was associated with reduced leg blood volume, supporting the occurrence of leg vasoconstriction. These events appeared not only at maximal exercise but onward above the respiratory compensation point.

Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
question. You showed  once  somewhere in the forum, that you  believe you can use  MOXY  for efficiency  in  bike fitting as well as  in RPM training .  Can you  support this idea  with accepted  papers.
Answer .

Effect of cycling experience and pedal cadence on the near-infrared spectroscopy parameters.

Takaishi T1, Ishida K, Katayama K, Yamazaki K, Yamamoto T, Moritani T.

Author information



Previously we demonstrated that the method to reorder near-infrared spectroscopy (NIRS) parameters against crank angle could serve as a useful measure in providing circulatory dynamics and metabolic changes in a working muscle during pedaling exercise. To examine further applicability of this method, we investigated the effects of cycling experience and pedal cadence on the NIRS parameters.


Noncyclists (NON), triathletes (TRI), and cyclists (CYC) performed pedaling exercises at a work intensity of 75% VO2max while changing pedal cadence (50, 75, 85, and 95 rpm). Physiological and biomechanical responses and NIRS parameters were measured.


NIRS measurements determined with the reordered NIRS change demonstrated significant differences depending on the factors. The bottom peak of reordered NIRS changes in muscle blood volume and oxygenation level shifted upward with an increase in pedal cadence in NON but remained unchanged in CYC. The reordered NIRS change demonstrated a temporary increase at the crank angle corresponding to the relaxation phase of the working muscle. This temporary increase was observed even in the highest pedal cadence in CYC. The difference in levels between the peak of the temporary increase and the bottom peak of reordered NIRS change (LPB-diff) for CYC at 85 rpm was significantly larger than that for NON. The results with NIRS parameters corresponded to changes in pedal force and myoelectric activity during pedal thrust.


The bottom peak level of the reordered NIRS changes and LPB-diff determined for blood volume are available to detect noninvasively the differences in circulatory dynamics and metabolic change during pedaling exercises performed at different pedal cadences and also to estimate the difference of physiological and technical developments for endurance cycling in athletes.

Juerg Feldmann

Fortiori Design LLC
Posts: 1,530
I get     a lot of mail in the last 2 month  on the question, whether we could not use  MOXY  and SmO2  trend   to  combine with lactate threshold.
 I do not like to go  back  on this discussion  anymore  as we did this in all details.
 So here a  simple  answer.
 Yes   if you  use lactate  and   any concept of lactate threshold  and you feel this is  possible  and you  can  find visually or  with any    algorithm the   BP  of  MOXY SmO2  as well as a you are confident that your lactate threshold idea  is  to proper one    for  sure  try to combine  and use    MOXY   to find your threshold and than use the common idea of  calculating your    training  zones. No problem with hat  at all.
 What I  cant'  tell you  is, on what muscle you  should place MOXY  and  as well I  can't  tell you what  step length is the proper  step length.
 Here a  last independent   paper    and we find the same  reactions.

Muscular differences in breakpoints of muscle oxygenation changes

Considering that the VL and GL were mostly studied independently in previous NIRS studies, we tested the VL and GL simultaneously to compare the two muscles, as the VL and GL are involved as a knee extensor and a knee flexor/ankle stabiliser, respectively, during cycling. The BpVL appeared earlier than the BpGL (p < 0.001), indicating that the oxygen supply-consumption balance in the VL was broken earlier than that in the GL during cycling IET. Furthermore, the BpVL had higher assessment ability (indicated by the higher R2a and lower RMSE, Table 2) for the aerobic capacity indices than the BpGL. One reason for the differences in the Bp of OI between the VL and GL might be the differences in anatomical and histochemical characteristics. Sufficient evidence has shown that the percentage of type I (slow twitch) fibres in the VL is lower than that in the GL (Edgerton et al., 1975; Houmard et al., 1998; Staron et al., 2000). Additionally, the activity of oxidative enzyme (citrate synthase) was previously reported to be lower in the VL than that in the GL (Houmard et al., 1998). Due to the lower percentage of type I fibres and lower activity of oxidative enzymes in the VL, the fast twitch fibres would be largely recruited earlier in the VL when the workload continuously increases, resulting in more anaerobic metabolism in the VL during moderate and high intensity exercise. The earlier accumulation of acidic metabolic substances in the VL might result in more H+ and a lower pH. Due to the Bohr effect, the accelerated dissociation of O2Hb would occur earlier in the VL due to the earlier accumulation of acidic metabolic substances; this result is indicated in our data by the earlier breaking up of the oxygen supply-consumption balance in the VL (BpVL). Another reason for the differences in the Bp of OI between VL and GL might be different usage patterns of the muscles during cycling. The mono-articular muscles (e.g., the VL) are primarily involved in the generation of positive work, whereas the biarticular muscles (e.g., the GL) are responsible for regulating force transmission during cycling (So et al., 2005). Additionally, the VL is thought to be one of the most active muscles during cycling (Hug et al., 2006) and seems to produce more muscle work than the GL over the crank cycle (Neptune et al., 2000). Therefore, the contribution of the VL is most likely higher than that of the GL during cycling, which might account for the earlier occurrence of the BpVL and the higher assessment ability of the BpVL for the aerobic exercise capacity indices. In summary, the differences in the BpVL and the BpGL might be mostly associated with the muscular differences in the percentage of muscle fibres and the usage patterns during cycling. However, further research with muscular biopsy and/or sEMG is needed to confirm this type of association.


 I like to foccus  on this forum  really on the  many options in all the different sports  we use MOXY    what  can you do  where  can we improve  and what is the limitation.

Jiri  Dostal  form Prag  put it   beauifully in an e mail this week

MOXY  Evolution or Revolution ???
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