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Development Team Member
Posts: 1,501
However, as she is a 100m sprinter and hurdler, heart rate has never seemed relevant. 
Not  sure about  that. The cardiac system is very relevant  for   survival.  It is   a difference   because  we  always  think  in  sprint  it is not  reacting.
 True  the lag time   is  too long , but there is  still the   protection of BP  after  any load  and there is the  CO  before  a load.
. So   yes  start to use  HR  and in the  standing and laying down  easy   experiment  you add  HR  and you can see how it  can be  used  as a indirect feedback on CO.
 t The tHb  reaction  has 2 main   directions.
 It  can drop  due  to muscle contraction pressure  and ity  cna  go up  due to vasodilatation  caused   for exampel by increase in CO  and here HR is  a part of it.
. So  the reactions if she  sits  down   and we look at tHb  and  possibly   gravity influenced  pooling  you  add HR  to it  and we have  some more feedback on this  and you add  correctional  diaphragmatic  respiration and you may  actually change the tHb reaction.


Development Team Member
Posts: 1,501
Thanks  to Craig's nice  track and field  example  and out discussion ion the recovery section after the second 150 m sprint  and the possible  reaction due  to " gravity "  I received  2  emails. They absolutely  with  their   terms  argue , that this is a nice  study  but in now  way  woudl NIRS  pick up this reactions. They believe it is  a nice story but  not backed  up  by science.
 Well  that is where   one of  the discussion points is. As   many time  mentioned .
Belief " moves  towards religion and needs  not  facts  to claim the   " truth. Somewhat  different  with science.
 NIRS  is one option  to   show  this facts.
 Here some independent  information on what we discuss here  and  as well what Craig's  small experiment  actually  shows.
  The more informed  readers  may start to see how  the different physiological reactions  can  be picked  up  with NIRS  and  if we need  facts  we than can  go back  to how we started by using VO2  and  Physio flow  and  blood sampling  to show  how  time lag  and  direct  feedback  can  support each otehr  when  the physiology  is   used  accordingly.  I  may show  some  fun  data    and the dilemma  we had in the past  when we   " believed"  on VO2  and lactate what we tested  and forgot  that the  unseen real is now    real  with MOXY  and the   unreal seen is  lactate  and  VO2

Gravitational forces significantly affect venous return, cardiac output, and arterial and venous pressures.  (  and  therefor  tHb  and SmO2 ) To illustrate this, consider a person who is lying down and then suddenly stands up. As the person stands, gravity acts on the vascular volume so that blood accumulates in the lower extremities. (Compare the size of veins in the top of your feet while lying down and standing.) Because venous compliance is high and the veins readily expand with blood, most of the blood volume shift occurs in the veins. Therefore, venous volume and pressure becomes very high in the feet and lower limbs when standing. This shift in blood volume decreases thoracic venous blood volume and therefore central venous pressure decreases. This decreases right ventricular filling pressure (preload), leading to a decline in stroke volume by the Frank-Starling mechanism. Left ventricular stroke volume also falls because of reduced pulmonary venous return (decreased left ventricular preload). This causes cardiac output and arterial blood pressure to fall. If arterial pressure falls appreciably upon standing, this is termed orthostatic or postural hypotension.This fall in arterial pressure can reduce cerebral blood flow to the point where a person might experience syncope (fainting).

When a person stands up, baroreceptor reflexes are rapidly activated to restore arterial pressure so that mean arterial pressure normally is not reduced by more than a few mmHg when a person is standing compared to lying down. However, in order to maintain this normal mean arterial pressure, the person who is standing upright has increased systemic vascular resistance (sympathetic mediated), decreased venous compliance (due to sympathetic activation of veins), decreased stroke volume (due to decreased preload), and increased heart rate (baroreceptor-mediated tachycardia). Patients with autonomic nerve dysfunction or hypovolemia will not be able effectively utilize these compensatory mechanisms and therefore will display orthostatic hypotension.

Without the operation of important compensatory mechanisms, standing upright would lead to significant edema in the feet and lower legs in addition to orthostatic hypotension. Venous pooling and reduced venous return are rapidly compensated in a normal individual by neurogenic vasoconstriction of veins, the functioning of venous valves, by muscle pump activity, and by the abdominothoracic pump.  When these mechanisms are operating, capillary and venous pressures in the feet will only be elevated by 10-20 mmHg, mean aortic pressure will be maintained, and central venous pressure will be only slightly reduced.

When a person is lying down in a horizontal position, gravity is no longer causing a shift in blood volume from the thoracic compartment to the legs and feet. Therefore, the thoracic (central venous) compartment has increased blood volume compared to standing. This increases preload on the heart, thereby increasing stroke volume, although the resulting increase in cardiac output will be tempered by a reduction in heart rate through vagal activation and sympathetic withdrawal. Sympathetic activation of the systemic vasculature is also reduced, which causes systemic vascular resistance to fall as the resistance vessels dilate.

Revised 01/07/10



Development Team Member
Posts: 178
From another thread: In this runners  case it  could be a due to  lack of muscle pump  and possible respiratory   weak diaphragm reaction. 

So I agree now about the lack of muscle pump effect. As I had mentioned, the athlete was coming back from an illness and her breathing felt difficult/restricted in her throat and upper chest after her run. So this probably also contributed. In her most recent session, which I posted with the experiment, she was feeling improved but still not 100%. That, along with a rest day prior and shorter reps was probably why the better SmO2 reading.

Development Team Member
Posts: 1,501
Craig  I  have a lot more feedback on the first  information as it is  fun to see, what we  can read out  and why physiological feedback  can help  for later ideas  Here  is  again the very different  approach we  have   
 the difference between a physiological assessment  we  do  and a  actual performance test  we  did in he past.  A  physiological assessment has the  goal  to find out limiter  at the current  day or  situation and   integrate  the limiter into the  plan. A  performance test  looks  for a maximal performance  which often   is done in a  recovered situation  and than we  find a  100 %  performance under   rare  and    optimal conditions  and hope this will apply  all the time as we base the  intensities on this one time optimal performance. Physiological  training is based on  current now  reactions of you body  so  we know  now  what we  can  do or no  can do or what we like to achieve.
 Performance assessments  like  VO2  max  %  calculation or   LT  calculations  hope , that we  react  every  day the same  and not take into consideration physiological  up and  down  like we  may see in this practical approach. So  the questions.
 Shall I simply  neglect  them or  push or shall I    listen to it and  try to  chnage the approach  now  as I see it.

I will  be back as I have  many graphs  form Craigs  great  workout   to show   a comparison  between  first  150 and second  and  hat happens in plyometric  and so on.
 Than we  go back to Craigs  initial question   why it made no  sense  and how  NIRS  can shed some light int the  athletes  reaction. Would we see, that with  the performance feedback  ?   Now  you can see why  when we started  this  fun  ideas we  used people  we  knew  limiters.  so  Respiratory  diseases  like COPD  or cardiac  limitation like a leaking vale  and  so on. There we   had  the information what is limitation and than we  saw the outcome in NIRS  and now we  can use it on anybody.

Development Team Member
Posts: 219
Just to add to the discussion of gravity see images.
Two test done in March of this year on a professional Yoga teacher see first image and on myself see second image VL THB FLOW Gravity.jpg 
VL THB FLOW Gravity BJ.jpg   The pink zones are the transitions to the next pose.
HR for first image 40 to 55 bpm and for the second image 55 to 68 bpm


Development Team Member
Posts: 369
Nice data bobby!
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