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Juerg Feldmann

Fortiori Design LLC
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 #1 
In red some possible answers or more questions to discuss.

I am not sure if this should be posted to the Forum, so will write it here, and let Juerg post it if it is warranted:
Please  come on the forum as  we all  have  more questions than answer and we  clearly promised to have a unique open  study group here with all the mistakes we make , wrong turns we take and hopefully once in a while a  answer we may be able to offer.
 So thanks you for this great feedback
This is an interesting discussion that came about from a simple first question.
The background behind the question was actually based on a much more practical aspect of assessment. The question we had was whether the MOXY was sampling often enough to pick up the differences in SmO2 values between contraction phase and relaxation phase during a single cycle rotation, and whether the number represented the AVERAGE SmO2 of the time period being tested, or some other value.

See first att. a closer look at RPM of 2 world class athletes during an IPAHD. look on the horizontal axis the time frame and you can see the RPM they had.
 The pictures show tHb as an indication of blood flow and we as well looked at the phase when it  changes O2Hb and HHb.
 I sent this picture once out to  some  cycling  guys to ask, where they believe we have a down stroke  from 12.00 to 6.00  and where is the upstroke   from 6.00 to 12.00 .  Fun answers we got.
Roger has stated the digital value is an average of 80 cycles over a two-second period, which is much faster sampling rate than I was expecting. Clearly, with 40 readings each second, the unit goes far beyond any human motion we would be looking at in sports, so the answer for me is very satisfactory.
 
Having the data averaged over 15-30 seconds would be absolutely fine, with the exception of VERY SHORT intervals, where we may be interested to see how quickly the recovery phase happens, but otherwise, the slower display rate would be easy to justify for the end user.

When we use  IPAHR  ( individual assessment of homeostasis recovery  ) in ice hockey we use a faster sampling rate of 1 sec .
 See second picture of an IPAHR on the ice with a NHL draft player done by Brian Kozak Next Level company.
 Yellow is tHb and purple is SmO2 or in this case HbDiff same trend. The  two lines mark the loading phase on the ice A- A as a  very short  full out load . the longer interval marks the recovery phase of the ice. This here was averaging the samples to 15 sec.
Brian used this to set up :
 1. Interval intensity of load and unload of SmO2 values.
 Interval Lent  and recovery Lent based on IPAHR
We continue to have some interesting results here. First field test subject was unable to clearly affect SmO2 results at intensity of HR=152. Second subject at slightly lower intensity able to CLEARLY affect SmO2 with breathing pattern changes.

Thanks great to see, that we are not  alone seeing the influence  on  MOXY  with respiration.
 See picture 3 and 4 . with one using different rhythm of respiration  in manipulating inspiration and expiration and the next one just using different RF under the same load.
 
One PROBLEM we have been able to identify. Deliberately slowing cadence, while maintaining power leads to a dramatic drop in SmO2 in every rider we have tested so far (this was another reason for our original question on sampling rate). The implication, is that while respiratory changes CAN affect SmO2 data, which could have profound implications for both training and racing, this data might be obscured by the more "normal" response of some athletes to change cadence under varying loads.
Yes RPM has a massive influence see  picture  5 from a very old study we did to show  at the University in Quebec with Andri many  years ago.  What we see here is the opposite form the case studies above a drop in  O2Hb ( therefor as well SmO2 as Hb Diff drops in fast cadence.
 Here another study done on this subject.
 

The effect of cadence on cycling efficiency and local tissue oxygenation

Jacobs, Robert MS; Berg, Kris EdD; Slivka, Dustin R. PhD; Noble, John M. PhD

Published Ahead-of-Print

 

Abstract

The purpose of this study was compare three cycling cadences in efficiency/economy, local tissue oxygen saturation, heart rate, blood lactate, and global and local rating of perceived exertion. Subjects were 14 trained cyclists/triathletes (mean age 30.1 +/- 5.3 yr; VO2 peak 60.2 +/- 5.0 ml/kg/min) who performed three 8 min cadence trials (60, 80 and 100 rpm) at 75% of previously measured peak power. VO2 and RER were used to calculate efficiency and economy. Results indicated that both efficiency and economy were higher at the lower cadences.

Tissue oxygen saturation was greater at 80 rpm than at 60 or 100 rpm at min 4, but at min 8 tissue oxygen saturation at 80 rpm (57 +/- 9 %) was higher than 100 rpm (54 +/- 9 %, p=0.017) but not 60 rpm (55 +/- 11 %, p=0.255).

Time  4 and 8 min   as well as by  8mn  by 60 RPM higher SmO2 than by 100 RPM  ???

Heart rate and lactate significantly increased from min 4 and min 8 (p<0.05) of sub maximal cycling. Local RPE at 80 rpm was lower than at 60 or 100 rpm (p<0.05). It was concluded that: 1. Trained cyclists and triathletes are more efficient and economical when cycling at 60 rpm than 80 or 100 rpm. 2. Local tissue oxygen saturation levels are higher at 80 rpm than 60 and 100 rpm. 3. Heart rate and blood lactate levels are higher with cadences of 80 and 100 than 60 rpm. 4. Local and global RPE is lower when cycling at 80 rpm than at 60 rpm and 100 rpm. A practical application of these findings is that a cadence of 60 rpm may be advantageous for performance in moderately trained athletes in contrast to higher cadences currently popular among elite cyclists.

 

Great example  on how we can  generalize some  small groups  finding or make statistic.
 Our  assessments where done with  very high level cyclists  and showed  the result as a case study suggestion more O2 use at high  RPM. In the above example from this group they had  more use of O2  at lower RPM.
 When using RPM with extreme cadence change like 50   and 100   we have to assess besides the RPM the respiratory influence . See here a great study    in  pictures on change in VE and RF ( BF ) and TV  with different frequencies. This opens the questions what changes more the   SmO2  reaction : respiration or   compression. As such we did  same testing with controlled breathing  and that's why we have this questions.

 See pic 6 /7/8 on reaction  of  RPM on respiration.
I would like to suggest to Andri, that for the purposes of the study, that the cadence for each test subject is recorded, and held stable throughout the test. Without accurately and aggressively maintaining cadence, I feel the test results could be called into question.

As well the  fun part would be to see, what the lycra  pressure  ( if this was used)arround  may have change from tHE pressure compared to a tape only . sEE cLINT  FREEZINGS GREAT CASE STUDY ON tsi AND  sMo2  CHANGES UNDER The SAME CONDITIONS WITH PRESSURE  CLOTHING. On te general q and A on this forum.



We discussed this suggestion as we designed the  protocol and the way we would like to proceed. The clear controversial information we gathered and the question , whether RPM or RF and TV  may influence the SmO2 more  was endless and as such we would have to tell people to maintain a proper RF and TV   to get rid of that variable.
That's' why we did not move a fixed or better stable RPM into the protocol but just do it this way but give us as much data's back. So people using a Compu trainer will have RPM  automatically included and we see, how they may have changed RPM  in combination with respiration.
 People with Taxc  can write as always the RPM down they told the person to stay in.
 The idea is  that in our third part of the study we would  go towards this case study assessments.
 
 As you can see  as  so often , playing around with a  cute toys  distracts from what we would like to establish from simple to complex  so just simply follow the  protocol  so we have a base line of data's to be able to go to the second part of the IPAHD setup.
 nevertheless this is fun but  get's us far of the topic  on what we like for the moment to achieve, but shows the huge potential of MOXY and its use for physiological reassessment and trainings.
 Thanks to this group for the great feedback.
 

Attached Images
Click image for larger version - Name: yama_gk_rpm_tHb.JPG, Views: 28, Size: 56.50 KB  Click image for larger version - Name: ROACH_ICE.jpg, Views: 29, Size: 70.88 KB  Click image for larger version - Name: resp_games_TSI.jpg, Views: 27, Size: 47.06 KB  Click image for larger version - Name: geoff_respo_games.jpg, Views: 28, Size: 72.92 KB  Click image for larger version - Name: RPM_workout_NIRS_controlled.jpg, Views: 30, Size: 107.11 KB  Click image for larger version - Name: VE_and_RPM.jpg, Views: 25, Size: 94.15 KB  Click image for larger version - Name: BF_and_RPM.jpg, Views: 22, Size: 94.53 KB  Click image for larger version - Name: VT_and_RPM.jpg, Views: 24, Size: 84.49 KB 

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