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Development Team Member
Posts: 217
Sebo thanks for sharing your race experience and love the video. What camera did you use to rec front and back view?

Development Team Member
Posts: 1,501
I feel that during my 5-1-5 my limiter was on respiratory side (main limiter was VL)  and during FTP was on cardiac side?

Yes    welcome in the  personnel kitchen.
 In all out loads   as mentioned , you load  the full team. So  you   will first overload  the   real limiter. But as it is a race  or  a highly motivated  workout  you still keep going as you have the option  to survive  by using   compensators. Now  earlier than later  the compensator  have enough as well and will finally limit your   high performance. You now  can quit  or  you have to slow  done, as the priority is  the O2  hierarchic  or pyramid.
Lets go  through  the picture  which  may start to make sense.

In a race  or    hard training based on  performance  you  load  the TEAM. You get the end result  of the teams  needs and performance. That's it.
 You miss for example  when  rower no 2  started  to  loose  the optimal strokes  per minute  he now just keeps  the    stroke  rate but no  power any more on the oar.
In a physiological assessment or  workout  you  try to find  who in the team start  to  push the limitation. 
 Now  2 main options. Just stopped  there  and  work individual  with this  rowers  to get up his  stroke rate  and let the three other work   on a higher  stroke  rate as  they  are  hold back  from the no 2 .
So  as   all have to stop  by stroke rate  40   only  No2    may  perhaps improve,  but as well may be overloaded. The other three really will get  worse , as they  never  really  push  their own limitation So  split  to boat  work individual  till No2   is able  to  get back  to contribute  to the team. In case of  specific  stroke rate  workouts.
 Or  change  so he can go faster  with different options  still in the same boat.

rowing race.jpg 

So  in an all  workout  like  your FTP    or  race  you overlook  the limiter  and  hope  for help  from the compensators.
If  your limiter is a vital system  like respiration in COPD  or  cardiac limiter like  after a  heart attack  , than you will have  no  real compensator,  as  you will shut down  the loco motor  muscles  first.

ecgm pic.jpg 

Now  you  look above  and you can see why the tHb is so crucial  when we look at NIRS. SmO2  is great but  we need the combination and the connection  in physiological terms  to understand  the reactions. So  top athletes  have   one additional gear, ob  nice we   start protecting the  vital  pO2  systems reaction. Blood volume  shift.

Are the arms and legs in competition for cardiac output?

Secher NH, Volianitis S.


The Copenhagen Muscle Research Center, Department of Anesthesia, Rigshospitalet, University of Copenhagen, Denmark.


Oxygen transport to working skeletal muscles is challenged during whole-body exercise. In general, arm-cranking exercise elicits a maximal oxygen uptake (VO2max) corresponding to approximately 70% of the value reached during leg exercise. However, in arm-trained subjects such as rowers, cross-country skiers, and swimmers, the arm VO2max approaches or surpasses the leg value. Despite this similarity between arm and leg VO2max, when arm exercise is added to leg exercise, VO2max is not markedly elevated, which suggests a central or cardiac limitation. In fact, when intense arm exercise is added to leg exercise, leg blood flow at a given work rate is approximately 10% less than during leg exercise alone. Similarly, when intense leg exercise is added to arm exercise, arm blood flow and muscle oxygenation are reduced by approximately 10%. Such reductions in regional blood flow are mainly attributed to peripheral vasoconstriction induced by the arterial baroreflex to support the prevailing blood pressure. This putative mechanism is also demonstrated when the ability to increase cardiac output is compromised; during exercise, the prevailing blood pressure is established primarily by an increase in cardiac output, but if the contribution of the cardiac output is not sufficient to maintain the preset blood pressure, the arterial baroreflex increases peripheral resistance by augmenting sympathetic activity and restricting blood flow to working skeletal muscles.



[PubMed - indexed for MEDLINE]


Cardiac output, and leg and arm blood flow during

incremental exercise to exhaustion on the cycle ergometer

Jose A. L. Calbet (1,2), Jose Gonzalez-Alonso (2), Jörn W. Helge (2,3),

Hans Søndergaard (2), Thor Munch-Andersen (2), Robert Boushel (3,4), Bengt Saltin (2)

(1) Department of Physical Education. University of Las Palmas de Gran Canaria, Spain

(2) The Copenhagen Muscle Research Centre, Rigshospitalet, 2200 Copenhagen N,


(3) Department of Biomedical Sciences, Panum Institute, 2200 Copenhagen N,


(4) Department of Exercise Science, Concordia University, Montreal, Quebec, CanadaJ.A.L. Calbet




To determine central and peripheral haemodynamic responses to upright leg cycling

exercise, nine physically active males underwent measurements of arterial blood

pressure and gases, as well as femoral and subclavian vein blood flows and gases during

incremental exercise to exhaustion (Wmax). Cardiac output (CO) and leg blood flow

(BF) increased in parallel with exercise intensity. In contrast, arm BF remained at 0.8

l.min-1 during submaximal exercise, increasing to 1.2±0.2 l.min-1, at maximal exercise

(P<0.05), when arm O2 extraction reached 73±3%. The leg received a greater

percentage of the CO with exercise intensity, reaching a value close to 70% at 64% of

Wmax, which was maintained until exhaustion. The percentage of CO perfusing the

trunk decreased with exercise intensity to 21% at Wmax, i.e. to ~ 5.5 l.min-1. For a

given local VO2 leg vascular conductance (VC) was 5-6 fold higher than arm VC,

despite marked haemoglobin de-oxygenation in the subclavian vein. At peak exercise

arm VC was not significantly different than at rest. Leg VO2 represented around 84% of

the whole body VO2 at intensities ranging from 38 to 100 % of Wmax. Arm VO2

contributed between 7 and 10% to the whole body VO2. From 20 to 100% of Wmax, the

trunk VO2 (including the gluteus muscles) represented between 14-15% of the whole

body VO2. In summary, vasoconstrictor signals efficiently oppose the vasodilatory

metabolites in the arms suggesting that during whole body exercise in the upright

position blood flow is differentially regulated in the upper and lower extremities.


Acta Physiol Scand. 1998 Mar;162(3):421-36.

Skeletal muscle blood flow in humans and its regulation during exercise.

Saltin B1, Rådegran G, Koskolou MD, Roach RC.

Author information

  • 1The Copenhagen Muscle Research Centre, Rigshospitalet, Tagensvei, Denmark.


Regional limb blood flow has been measured with dilution techniques (cardio-green or thermodilution) and ultrasound Doppler. When applied to the femoral artery and vein at rest and during dynamical exercise these methods give similar reproducible results. The blood flow in the femoral artery is approximately 0.3 L min(-1) at rest and increases linearly with dynamical knee-extensor exercise as a function of the power output to 6-10 L min[-1] (Q= 1.94 + 0.07 load). Considering the size of the knee-extensor muscles, perfusion during peak effort may amount to 2-3 L kg(-1) min(-1), i.e. approximately 100-fold elevation from rest. The onset of hyperaemia is very fast at the start of exercise with T 1/2 of 2-10 s related to the power output with the muscle pump bringing about the very first increase in blood flow. A steady level is reached within approximately 10-150 s of exercise. At all exercise intensities the blood flow fluctuates primarily due to the variation in intramuscular pressure, resulting in a phase shift with the pulse pressure as a superimposed minor influence. Among the many vasoactive compounds likely to contribute to the vasodilation after the first contraction adenosine is a primary candidate as it can be demonstrated to (1) cause a change in limb blood flow when infused i.a., that is similar in time and magnitude as observed in exercise, and (2) become elevated in the interstitial space (microdialysis technique) during exercise to levels inducing vasodilation. NO appears less likely since NOS blockade with L-NMMA causing a reduced blood flow at rest and during recovery, it has no effect during exercise. Muscle contraction causes with some delay (60 s) an elevation in muscle sympathetic nerve activity (MSNA), related to the exercise intensity. The compounds produced in the contracting muscle activating the group IIl-IV sensory nerves (the muscle reflex) are unknown. In small muscle group exercise an elevation in MSNA may not cause vasoconstriction (functional sympatholysis). The mechanism for functional sympatholysis is still unknown.

However, when engaging a large fraction of the muscle mass more intensely during exercise, the MSNA has an important functional role in maintaining blood pressure by limiting blood flow also to exercising muscles.

And to give the flowers  where they belong.  Hunter  already over  200 years back postulate  the  pointedout that blood  will go where it is needed.

So here our   idea in a  picture

a ) First we have to  survive. You see Cannons idea  and our  idea on who  to back  this up and what equipment we used .


now look  this  idea below.

O2  hirerchie.jpg 

So in a  race  you end up  on the  top  asking  all to contribute  no mater  how  efficient  and good it is  just  try  to hold on  the performance.
 In a  physiological training  you decide   who you like to integrate in a  workout  and why.

No  speculation to your  case:

Driven by a performance based training program  you learned  perfectly  to achieve the performance goal. In the    route  to the goal  you always needed  the VL  and  no matter  finally what you do  he is ready to help  as soon you are on the bike.
 Problem he has to  do   most of the load.
 he knows  that the body    learned  that  and what ever  you do you    push him to the limit and in some cases may ask one or the other  muscle group  or systems  to step in.
This is in survival mode  you  add other  potential  muscles   used in cycling. 
 Unusual  situation and you create a lot  of CO2  as  many of  this  muscles now  are not very efficient  in delivery but  even worse in  utilization.
 Your H  +  is going out of  balance.
 H + is not  a reason of f ailed   muscle contraction  as  so many believe.  You can add   H +  and you can have a low pH  it does not interfere  with muscle contraction or power production. This is another reason  why lactate can not en used  as  an indirect feedbag on a  too low  pH  Here below one  of many great studies  in that  direction.

Muscle Nerve. 1993 Jan;16(1):91-8.

Dissociation of [H+] from fatigue in human muscle detected by high time resolution 31P-NMR.

Degroot M1, Massie BM, Boska M, Gober J, Miller RG, Weiner MW.

Author information                            

  • 1Magnetic Resonance Unit, Veterans Administrative Medical Center, San Francisco, CA 94121.


Previous in vivo studies of skeletal muscle fatigue have demonstrated significant relationships between the decline of muscular force and changes in muscle metabolism. However, these studies performed measurements over relatively long time intervals or during steady state exercise, thereby obscuring rapid metabolic changes occurring at the onset of exercise and recovery. To overcome these limitations, fatigue of human calf musculature during sustained isometric foot plantar flexion was quantified continuously as the decline in maximal voluntary contraction force (MVC), while concentrations of phosphocreatine (PCr), inorganic phosphate (Pi), intracellular free hydrogen ion (H+), and monovalent phosphate (H2PO4-) were simultaneously measured at 2-second intervals by 31P nuclear magnetic resonance.

 The first major finding was that [H+], which has been thought to be a mediator of muscle fatigue, actually declined during the first 10 seconds of exercise when force was declining and rose immediately postexercise, when force partially recovered.

Second, the correlations of [H+], [H2PO4-] and Pi with MVC during the first minute of exercise were determined to be curvilinear and not linear as previously suggested. Furthermore, using either a linear or curvilinear regression model, [H2PO4-] and Pi demonstrated a closer correlation to MVC than [H+] during the first minute of exercise. Thus, these results reveal nuances in the relationships of MVC to metabolites previously undetected by low time-resolution measurements. These findings suggest that during sustained isometric exercise, rising [H+] is not likely to be the sole mechanism of muscle fatigue and are consistent with the view that a rise of Pi or [H2PO4-] is a major causation factor in force reduction.


This leaves us  with  the idea  back  to survival   (  energy  or  O2.)
 If  we  can not  deliver  O2  we have a problem. So  even though  high H +  or  low pH  may not  reduce muscle strength  they inhibit  O 2 supply  ( O2  dissociation  curve. )  so we have O2  but it is not bio available.)  this creates  the  dilemma for any body  who believes  they can use  lactate  and SmO2   to find  what ever they  try to find.
  We  can have a  drop in SmO2  but  as well a  drop in  lactate.
 We  can have a drop in SmO2  but an increase in lactate . we can have an increase in  SmO2  and a  drop in lactate and we  can have a  increase in SmO 2 and  an increase in lactate. Now  you us a  systemic lactate testing idea  with a punctual   NIRS feedback  and   we  can keep dreaming .
  Now  VL   runs into trouble , you keep going  you already create some  H + in the  perfect  and super hard  working  VL . You add a  long  time unwilling  RF  or   Hamstrings  guy in it. Not yet ready  to contribute  and early  limitation in delivery   ( vascularisation  but as well in utilization ( mitochondria density )  but a  person   trained  to push  the pyramid. So  you shut  down  delivery  due  to cardiac  and respiratory  limitation now  and you  try to shift  some blood . After  a  hard  race  you immediately shift  first  from one  not priority  area  to priority  area  in case  you have to go once more   and   vital systems  did not yet recovered.

 The integration  of non trained  leg muscles  adds to the pH  and H +  dilemma . The O2  disscurve  shifts  more to the   right. Still O2  there but not bio availability. Bad loading in the lungs  to the  blood, High CO2    and you reach your respiratory limitation which finally     create a problem  for your cardiac systems .  So  FTP  end   tHb  drop  due to cardiac limitation  as  you  after   the load  open   too many blood vessels. CO  can not    keep central venous BP  and you  will create  a protective vasoconstriction.
If  this  does not works you will get dizzy. You can sustain  that somewhat by not  stopping immediately  so your muscle compression  will help  to maintain the BP  easier.
Why in a race  the  first three  rarely  collapse . They    keep going to celebrate. The worst  collapse is always the  4  th in a race  ??? Exceptions  are sports , where  the whole body is involved  ( Rowing  cross country  skiing  and triathlon   WHY ?? Even winners  often collapse.
Have  fun to read  swenglish.


Development Team Member
Posts: 227

Thanks a lot this makes perfect sense, Moxy is true eye opener, for last month and a half I have dropped intensity by 50% and I feel I made bigger progress then in previous 6 months.

I'm blown away that most, if not all coaches I know have no clue about this, I feel they all follow predefined sets without understanding why they do it, and concentrate more on motivational training that physiological training, kinda "shrink" therapy instead of actual training. 

Here is what got me thinking about proper training and pushed towards Moxy:

Imagine 10 people in the spinning class with "respected" coach we all follow the same program, you look at those people and see: one is sweating like a pig, other has casual conversation with the colleague, third is huffing and puffing minutes form chocking himself to death, other is red on his face like just came from 4 hours sun bed despite the fact it is mud January in Canada.

I was always thinking who the hell is really improving out of those people, and what are they really improving??? Our coach says it is strength session, but it does not relay look like we are all working on the same thing....

Now I understand we all have different limiters and following some predefined plans will improve some of us to certain extent, but it is far from perfect as it might build huge imbalances.

This is  great experience, I'm glad I took the dunk and got myself Moxy, I think this was the best purchase I made so far besides my bike[smile]


I have GoPro 3+ front and back, battery last over 3 hours and with extended pack 8 hours.


Development Team Member
Posts: 227

Here is one more recent addition to my case.


I was super excited to work on my hamstrings and RF, absolutely crazy excided, I felt I’m getting stronger and stronger literally every session. Sprints felt better than ever on the trainer and I’m going only at 80% not more.


Best of all I’m doing progress while doing work in Oxy-Balance zones 170W-220W, I would never be in this zone ever without moxy, I would be hammering Vo2max and Sweet Spot and making no progress at all.


So I’m getting all excited and thinking, I need to up the game a bit, how about I will increase intensity and frequency of those workouts.


Last Tuesday I was doing some slow cadence session with emphasis on hamstrings, then next day on Wednesday pulling my leg up with hamstrings again and bam!!!!

My injury from 4 years ago came back, got muscle spasm sciatic nerve shock through my body.


While Lying on the floor I’m thinking holy $^#%  I was back pain free for so long…and it all clicked together, when I use to have those back pains years back, I learned to pedal a bit differently causing my imbalance: I moved my saddle forward so I’m not stretched and start doing most of my work with VL without any addition or help from hamstrings and other muscles. Once I started to engage other muscles too much too quickly injury came back.

At list I have a clear picture of what it means too much now, and too much in my case was really not that much…. 


Development Team Member
Posts: 369
Sorry to hear about that sebo! In South Africa one of the local african languages have a phrase "eish" - basically translated it means "oh my gosh" ...when something goes wrong, thats the term that came to my mind.

Heal up quick

Development Team Member
Posts: 227

Thanks Ryinc, 

I read what I wrote and I take back words “not that much” I’m use to classic ideas of stupid power zones, and my Zone 2 endurance, doesn’t feel like much, but this is because it is very limited zone that again doesn’t really mean anything.

If I would already switch fully to Moxy without peaking at power every now and then, I would not get injured.

Just to give some background, I could efficiently deoxy my hamstrings only 3-4 times for 50-60 seconds, then every next attempt I could not go as deep as in first attempt, it is good sign to STOP I know, please slap me now.

But I look at power and see 220W and I’m thinking Oooo… I can easily pull another 4 of those, and that is big mistake. At this level my hamstrings were already at max, so they were not at zone 2 but zone 7 (again just comparison for power zone people) would I normally do Z7 daily training on anything? Noo…

But beyond anything, why am I even doing such a hard intervals on such a weak muscles??, I should be taking easy for long time in Oxy zone trying to build some strength, but again I look at Zone 2 and thinking I can go much harder. That is the biggest problem when training with both power and Moxy. Power gives us one zone structure that completely doesn’t relate to actual weaknesses, if we want to work on those weaknesses we absolutely can’t use power as guide or we will end up injured sooner rather than later.

Moxy gives us ultimate incredibly granular guide how hard we can push each individual muscle and system. 


Development Team Member
Posts: 1,501

Seboo  you  wrote it  very nice   and    what I  try to  explain always is.
 There is a physiological  load  and there is  an  outside feedback.
 The physiological load  or stress  does not care  about  the outside   feedback but  about the ability  to actually create  the  energy ( use O2  )  to be able  to  do the   task.
 If  you reach the   THE limiter    ALL OUT  ABILITY  ( that's why  it has the name limiter) and you simply overrule his  cry  for  help  or to stop than you attracted  the   possible compensator. Now in some cases  that is  what you like to  do  and in some cases it is a terrible idea  for the end results  you may  work towards. An exampel is   the  often seen picture in  cyclist  we have on here, where the VL  desaturate very nicely and fast and  than reaches a  flat  SmO2 level.  Tk hats very often where  you start to  just maintain the  power    created  by this muscle and if  you add  the next step   ( more wattage )  you  will atract  an other muscle group like  the  RF  for example.
. So one of the problem is , as  you can see  that in the  80  %  plus LSD  you may never really go  and attract  the RF   so you have a huge fiber  dysbalance  between RF  and VL and VL.
  and if  you go hard   like classical VO2  max  +  and so on  you  push  so hard  that  again  you  do not attract the  same   way  you  create  ATP. So  you keep  the fiber  dysbalance    despite very hard  workouts.
 So  the key is  to go  slow  with  concentration as  you started  out  but there is a certain physiological  tie line in developing the ability  and  that  is  3 month and  more if  you look for a  cook book.
 So   go back  to what you  did great  and power will come on its on  as  there is a direct link  with  the  ability  to   deliver  energy  and the power  you like to produce.  I will  possibly  try to explain later  the  problem we  have with understanding outside power  and  inside  ability  to actually have the energy sources  to create  the   visual  outside power.
 It is  an many may start to understand  the  Greeks  idea.
 The unreal seen seen (  which is power )
the unseen real ( which is  physiological reactions )    I  you like to make progress  you have to control the unseen  real   and not  the  unreal seen.

Here a practical  example  of a 400 m runner interval.  Look at 400 m runners.
 100 m  extremely  smooth  and  dynamic and power full   next  100 m  extremely  smooth  and  fluid.  next   100 m  looking okay but less dynamic  and less optimal body position.  last 100 m  all is over   legs  tun  sideways  and rotate  no  clear  hip extension and so on. The   compenstor took over   there is  just one goal  to survive  and nobody cares , whether and  who contributes  to  reaching that finish  line.
 The glut  and  hamstrings  chain as  optimal hip ex tensor are    gone  and the hip rotator  and   add-  abductor  take over. this creates a very different  pattern and load  on  for example Achilles tendon  and  foot  muscles , tibial  bone area.
 Result  is ??   ask a  track coach because  you add metabolic  acidosis    to it  with some  Ca++  reduction..
 So  what is the point in a  10 x 400 m run  to train really   survival of  10 x   relative lousy 400 m   runs  with a poor  quality ?
 Now in your  case  when you  tried  to activate  hamstrings as a part  of   6 - 12  motion  together  with RF  you  overload them if  you go  too  hard (  reach  SmO2  low levell )  and  as you  try to survive  you simply add some more commentator  to it. In that case  one   you may attacked is the psoas  section  for  your iliopsoas  muscle. Google  where  he  comes  from and than think  what  seems  to   create  your  sciatica  flair  up.


Development Team Member
Posts: 217
Speedy recovery Sebo

Development Team Member
Posts: 227

Bobby thanks,

I had quite a problem with my lower back years ago, I quickly learned how to recover from those incidents by stretching etc, but really without deep understanding, I was just doing what feels right.

After visiting 3 different doctors and listening about surgery etc. I just didn’t believe them.

I ended up with Chinese doctor (thanks to my wife, I was very skeptical, I’m not anymore) and acupuncture, after first session I felt 90% improvement, back then I didn’t understand it was just muscle spasm that was quickly remediated with needles, literally strong “muscle crap”

When Juerg said “psoas muscle” now it makes perfect sense, I have full picture.

I have office job, so I seat on my a$$ for 8-9 hours, I try to get up and go, but there are days when I’m too busy, psoas muscle shrinks. Then I come back home and train “hard”, my VL imbalance explains my pedaling technique change, when my pedaling was more fluent, I was getting back attacks since I was using RF and hamstring way more that I’m now. So I switched to VL only and I was back pain free for 4 years, my body was adjusting to avoid injury.

Now recently I went back to engaging RF, hip and hamstrings the way they should be engaged, also did a lot of pulls 6-12. On top of that it is busier than usual period at work that keeps me in the chair, and I totally understand why it happened now.

Juerg I just want to say THANKS!! You are incredible, all the symptoms I had during those attacks are exactly described here:

 I’m not going to focus on my bike now, but on other muscles that were neglected for so long, it was all due to my goose chase for higher FTP….

2017 will be the best season yet, I can feel it.



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