Hands-on with the Moxy Muscle Oxygen Sensor


Back about 45 days ago during the ANT+ Symposium I had the chance to sit down on a trainer and suffer through a nearly hour long test of both my physical fitness, as well as the Moxy Muscle Oxygen sensor.

It’s actually a sensor I’ve been poking at on and off with for about a year in a handful of rides and runs on my own.  But the time spent with founder Roger Schmitz gave me some time to dive into how it works in a structured test case with multiple sensors and data channels recording, and purpose made apps presenting the data in real-time.

Many of you have asked how the Moxy compares to the BSX device that I also tested in September.  Despite being a seemingly simple question, it’s a bit of a complex answer that spans a lot of areas.  I’ll try my best to explain it in the clearest method possible over the next few dozen paragraphs of text – though, even that might be challenging.  With that, let’s begin!

The Device Itself:


When it comes to unboxing the Moxy device, they take the cake for the fanciest box ever used in a fitness device.  I can only assume someone was trying to offload US Government seized Cuban cigar boxes, and this was available at a good discount.  No worries, it keeps it nice and protected and adds some swank and swagger.

Additionally, they’ve got a slew of ‘mounts’ (for lack of better term) that comes with it along with the carry tote.  Seriously, this device is stocked when it comes to ways you can carry and safeguard it.


As for the device itself, the Moxy is essentially an optical sensor, albeit, a bit of a chubby one.  But that’s OK, you don’t need to wear it on your head or your chest.  These little dots emit light that is then read and analyzed.  The slightly larger top dot sends out the near-infrared light, while the bottom dots are NIRS detectors that receive the scattered light from your muscle tissue.


To see the size differential, here’s a simple heart rate strap transmitter pod.  It’s about the same length, but is deeper and slightly wider.  On the bottom there is a Micro-USB port for charging and downloading.  The whole thing is also waterproof, but they still recommend putting it in small plastic bags (seen above) to protect it further.


The Moxy typically straps to your thigh, though it can attach to any muscle you can find a way to affix it to.  On your thigh the unit would use a molded system they’ve made, attached with some stickers. You can see the back of the sensor below:



The reason for the black rubber enclosure is that like other optical sensor systems, external light is the enemy.  Like Darth Vader style enemy, even more so sensitive than typical optical HR sensors are to outside light.  So there’s a bit more that they have to do to ensure that no external light gets in.

In my case, they applied the rubber casing to the Moxy sensor, and then taped the sensor onto my thigh.  I then slid my cycling shorts down over it, adding more cover of darkness.  It would be like Seal Team 6 in there, minus the tell-all-book.


In my test, for the fun of it, they also placed another sensor on my upper arm, to see how things differed during the test and to show variations with everything from how my arms were positioned to which muscles were actually doing the work.  You can see it just below my cycling sleeve under the word “Alpe”.  Further, I had the Scosche optical HR sensor on below that (seen outside my cycling jersey with the fabric band).


Speaking of which – now’s probably a good time to explain exactly what Moxy is measuring.  In this case, it’s Muscle Oxygen Saturation – aka SmO2.  To let the Moxy folks be more precise in that explanation, they note that:

“This is simply the percentage of hemoglobin that is carrying oxygen within the muscle tissue.  Hemoglobin is the molecule in red blood cells that actually carries oxygen from the lungs to
where it is needed in the body.  The measurement of SmO2 takes place in the capillaries of the muscle.

This is where the oxygen is being consumed. SmO2 can be thought of as a measure of the balance between demand increases, but the heart hasn’t had a chance to speed up, and the blood vessels in the muscle haven’t dilated. The SmO2 drops quickly in these conditions.

As you warm up, your heart rate increases, and the blood vessels in the muscle dilate to 2 levels. When you stop exercising, the demand for oxygen suddenly falls, but the heart rate is still elevated and blood vessels dilated. At this time, a rapid increase in SmO2 is observed.

Generally, higher levels of exertion in the muscle lead to lower SmO2.”

So essentially you’re looking at how your body, specifically your muscles, responds to exertion over time.  And the numbers you’ll get are sorta like a test score.  For those interested, you can dive into more details from their site here in this PDF on how exactly the device works.


Finally, all of this is then transmitted over ANT+ from the device.

The unit transmits across ANT+ in two different ways.  The first is that it can fake being an ANT+ Speed/Cadence Sensor or the ANT+ Heart Rate profile.  Within those profiles it’ll transmit the data via those standard channels to virtually any tri/bike unit on the planet that supports ANT+.  This means you could easily use a good old reddish colored Garmin FR305 to collect Moxy data.


The second option, is to use the new ANT+ Muscle Oxygen Profile.  For this, you’ll need one of a handful of apps out there that can understand and record/display the profile.  These are listed here, but the major ones are Peripedal & PerfPro (bike trainer apps), and then IpBike (Android app). IpBike is handy because it’s just your Android phone and is more portable than a trainer app (and ANT+ is natively supported on many Android devices these days).  Meanwhile, the trainer apps are nice because they can specify the structure of the tests for you.

Then there’s actually one last option – which is to simply record the data to a file that you can download afterwards via USB cable.

The Test (and pain):


You know when something sounds like a great idea weeks in advance?  Almost invariably, it’s a horrible idea the day it comes to fruition.  I last had this occurrence just a few weeks prior with the BSX test.  Seemed like a jolly fun time in Vegas, until they explained I had to have blood drawn every couple minutes.

Turned out my thinking was equally flawed here too.  I figured how bad could a bike FTP/VO2Max-eqsue test be?  I’d be done in a few minutes and onto some sort of filling Canadian meal in the mountains.  What I didn’t account for was being at 1,522m (4,009ft) of elevation, nor the cumulative effects of multiple transoceanic boomerang flights in the preceding weeks. Nor that the test was slated for over an hour long.  Turns out elevation hurts.  A lot.  No pain, no gain, right?

The test structure was already laid out for me.  My job was mostly just to follow along.  We had planned to use a random trainer along with one of the random bikes lying around the ANT+ Symposium.  However, it turned out when two random’s are added together, they don’t always equal a right.  In this case the only working combination of trainers/cassettes/wheels/power meters/pedals we could come up with was a bike that was slightly too small without clip-in pedals on a trainer that couldn’t specify an exact wattage.  No worries, I’d just brute force it.

Normally, you’d want to use something like Peripedal to automatically control the trainer – such as the Wahoo KICKR.  In that case you’d be able to setup the test profile ahead of time, which was specified as as series of dual steps that were going beyond my FTP.  In my case, we had specified slightly higher goals, but with the last minute changes we had a bit less control.  Here’s my steps (after the all-important warm-up):


Each step lasts a rather painful 5 minutes, with then 1 minute in between.  Each step is repeated twice.  So basically, a little part of you dies inside twice for each step.

These were based on my FTP (Functional Threshold Power – The max wattage you can hold for an hour), which I roughly knew ahead of time.  Otherwise, a coach would be able to give you a good set of wattage steps.  In my case, they used 315w as my FTP, and then the steps were constructed from there.  The only challenge is that didn’t take into account the altitude, which definitely had an impact on me.

In any event, we got the test started:


As you can guess from the above listed steps, it starts off pretty easy.  That’s by design.  The goal is to understand your responses at a variety of levels.

The test was programmed into PeriPedal, but in my case I ended up on a BKOOL Trainer.  Unfortunately, 3rd party apps can’t control the BKOOL Trainer, so we ended up using the the BKOOL velodrome option and then I just pedaled/geared harder as required to stay at the right power output.

Below, you can see the first few 5 minute steps.  These are reasonably easy at this point since it’s below 300w.  Or, if not easy, at least sustainable.  Along the bottom you’ll see the Muscle Oxygen and Total Hemoglobin displayed.


Ifor Powell, who creates the Android app IpBike happened to be there – and he was tracking along the values on the app as well.  His app is the only mobile phone app that can record the Muscle Oxygen data (as well as display it live).


Eventually, you get to the part in the test where things start to hurt a bit.  These are 5-minute steps, and while the first chunks were easy, once you start hitting 350w for 5 minutes each (at 4,000ft), it hurts.


Of course, everyone else in the room found my pain funny.  I was doing the test just as the product faire at the ANT+ Symposium was wrapping up toward the end of the day.  You’ll remember the ANT+ Symposium is where all of the industry’s lead engineers and sometimes company founders are present.  So basically, everyone who has products that I review and pick apart…stopped by to watch me suffer.  Apparently payback.


Back to the test, you’ll remember that each step has a 1 minute break between them.  This is where they can see how quickly you recover from an muscle oxygenation standpoint.

Of course, in my case, that assumes you can get through the tests.  In some cases, the test will break you.  And that’s perfectly fine.  That was the case here for me.  After nearly an hour, and at little more than half-way through the 1st 450w 5-minute set, I simply couldn’t turn the cranks any more.  Defeat.


While I suspect that had I not been riding in running shoes and been on my bike at sea level I would have faired better, that’s OK, it still gives me a general idea of where I stand.  And in this case, it gave me a good idea of how the platform works.

Ray 515

Above is the final chart from Peripedal showing my test results in real-time, from there we’d export it out and get it to .CSV format for analysis.  Note that Peripedal does all sorts of other trainer things, we were just using a small fraction of it.  But I’ll cover the trainer features tomorrow in a different post.

Now, while I’ve talked about some apps as a way to record the data, you’ll soon also have the Garmin FR920XT with Connect IQ as well.  In fact, Moxy was the device/sensor that Garmin used in almost all of their demonstrations for Connect IQ.  Demo apps and all were written with the explicit the idea of using the Muscle Oxygen profile that only Moxy leverages.  Of course, not to be outdone, the Moxy folks are working on their own app for Connect IQ as well.  So collectively, you’ll be well covered there for recording data directly to Connect IQ capable devices (currently just the FR920XT until next year).

Analyzing the Data:


Now, next comes the ‘fun’ part.  Or, in some cases, the road less travelled.  This is where you see significant differences between a product like BSX, and that of Moxy.  In the case of BSX, they’re aiming to give you a complete recommendations set – a full set of automated reports with specific training guidance.  Whereas with Moxy, it’s aimed at the coaching level and their goal is to give you specific raw information that you or others can then leverage.

To begin with, they showed me some graphs of how a typical Elite cyclist would respond to a 5-1-5 test (which is the test I did – 5 minutes on, 1 minute off, 5 minutes on, repeat).  In the above image you can see how it takes a bit of time to stabilize, and then in each set you can see the Muscle Oxygenation (SmO2) level get progressively lower and lower each set.  You can also see how it recovers less as the cyclist went along.

Next, here’s my data, first plotted against power:


But, let’s remove the power component in order to make the scale of the graphs pop out a bit:


Now that’s much easier to see.  You can see my muscle oxygen level (%) is steadily going down, but it’s my final incomplete attempt that you really see it drop significantly towards the end of that set.  It’s this specific drop that they’re really looking for in the test.  At this point, while another step would have been interesting, it wouldn’t have been needed – they’d reached the point where there’s a sharp drop-off.

But, check this out:  Here’s the MOXY sensor that was on my deltoid (upper arm near shoulder).  You can see that by and large there was fairly minimal fluctuations until that last set.  It’s unclear if this was because I was getting more active with the trainer (i.e. standing/moving/etc…), or just the result of ‘all hands on deck’ in my body to fight through.  Still, it’s interesting.


So, what do you do with all this data?  Well, there’s a lot of ways it can be used.  First it can be used to determine your specific area of weakness in the body and the delivery (or lack thereof) to the muscle.  A number of higher end/elite athlete coaches are looking at Moxy data from that specific side of things.

The second way of looking at the data is for a coach to establish zones based on it (such as power zones).  The below graph gives an example of that (not my zones, just a sample).


The zones identified above are:

Green (AR): Active Recovery
Yellow (STEI): Structural Endurance Intensity
Orange (FEI): Endurance Intensity
Red (HI): High Intensity

Of course, coaches would likely call these other things (i.e. Zone 1, 2, 3, 4), but the structure is there.  The idea being though is that the above zoning then aligns to the specific event you’re training for (as usual).  But to extend that, you could then re-test the theory of a specific zone by doing a longer steady-state workout exceeding 50 minutes at that specific wattage and the oxygen level should stay the same.

Now coaches that are using Moxy more deeply would note that using zones based on HR or power is effectively dumbing down the NIRS data.  And there’s truth to that.  But there’s also a reality that most of us in this world can’t ride with yet another $1,000 sensor strapped to us on every ride and run, especially if the battery life is only 6 hours (far too short for an Ironman, for example).  So compromises are likely to be made.

But – and here’s the thing that Moxy will outright tell anyone – there’s aspects of using the data that are still open to interpretation and study.  The ability to have a muscle oxygen sensor data in this footprint simply hasn’t been there yet.  Previous finger-clip style pulse oximeters didn’t see much shift in SmO2 because they were attached to the wrong parts of the body for athletes.  Just like you didn’t see much shift when the other sensor was attached to my arm.  Further, the Moxy sensor is simply measuring deeper and more detailed information.  But again, using that information can be the tricky part.

Some Final Thoughts:


The technology is definitely cool, with lots of potential in many areas.  For example, rather than measuring the ‘effect’ of something, this is actually measuring the direct attribute or cause.  Whereas many other techniques focus on measuring resultant changes, versus measuring the specific changes in the muscle oxygen level via NIRS.  The same technology could be used within sets to determine the precise moment you’ve recovered.  Right now, you just hope you’ve recovered between a set.

Of course, the obvious challenge is that this stuff is complex.  It’s not easy to understand for most athletes.  That’s a fundamental difference between what BSX aims to do, and what Moxy is doing.  BSX is looking at a holistic solution that gives you clear guidance.  Whereas Moxy is looking to utilize their devices within the hands of coaches that want very specific NIRS data to be able to coach athletes from (or, self-coach).  Moxy is available today (and has been for a year or so), while BSX is almost shipping.  Neither method is right or wrong, just different.  Measuring slightly different things.  In fact, you’ll find both companies are generally fairly cordial to the other.

The coaching driven aspect is no doubt core to why the price is what it is at $999US.  Whereas BSX is roughly 1/3rd the cost for the cycling or runner edition, but a bit more for the multisport edition.  Whereas Moxy can be used for any sport on any accessible muscle.  Again, different strategies.

If you’re either coaching, or looking at using the technology – then I’d spend some serious night and weekend time diving into how each solution works.  The Moxy blog is mind-bogglingly detailed in posts out there on the technology and different scenarios.  And the BSX blog is equally deep.  Meanwhile, with BSX ideally shipping in the next month or so, you’ll likely start to get some real world usage there as well.

Definitely an interesting time in this field!

As always, thanks for reading, and feel free to drop questions below and I’ll attempt to get the answers.  Even if said answers go slightly above my head.

(Note: I’d like to thank Ifor Powell, who willingly took over my camera during the test and documented my pain at an impressive #winning level of 449 photos.  I appreciate it!)


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  1. Aham23

    I see no fans which are a must for this type of indoor effort. You’ll otherwise overheat and blow up.

  2. Derick

    Nice to see IpBike getting some mention. It’s pretty amazing what Ifor has done with that app.

    • Yves-Marie

      “Nice to see IpBike getting some mention. It’s pretty amazing what Ifor has done with that app.”

      Dedicated man for sure !

  3. Néstor

    Hi Ray. Are you using Moxy in your trainings since you have it? If you do, what apps use you to analyze the data? Thanks for all your post.

  4. Fabio

    Hi Ray,
    Correct me if I’m wrong, but I assume both devices aims at the same goal (perfomance right?). However, each one does it on its own way.
    Based on that thought, do you think the crossover between data gathered from the BSX and the Moxy would have useful information? I mean, both devices gives extremely detailed data and undoubtably valuable information, but if all that data is used together do you think it would be useful or overwhelming?

    PS: From a coach standpoint

  5. Jeff

    Going forward it’s going to be interesting to see how the data explosion provides new training insights. For the time being, we know that figuring out one’s aerobic and anaerobic thresholds is useful for training (VO2max has never served much of a purpose). The ability to see how those thresholds change in real time, in response to training load or environmental conditions, for example, could be useful, and was impossible with a laboratory-only approach to testing.

    As a middle distance runner, I’d be fascinated to see data on what’s happening during highly anaerobic efforts. The ability to get that data in real time could facilitate training sessions that are more tailored than anything that’s been possible before. It could also help athletes to avoid leaning too heavily on their anaerobic system during periods far from peak competition, though most athletes are able to do that pretty well by feel.

  6. Sylvester Jakubowski

    Ray, you should do a post/interview with Ifor Powell, ipBike is miles ahead of any other mobile app for cycling.

    • Very good idea. I would also like to read the interview. ipBike is really great and Ifor does a great job.

    • H M

      Yeah, I’d like that too. I use iPbike whenever I ride outdoors, not that I use all the features but then I don’t have all the gadgets on my bike that Ray does…
      However I like the idea that if I ever were to get an exotic device (BSX /Moxy etc…) it would be supported as things tend to get added to iPbike almost before Ray has had a chance to write about them
      It basically does everything I want from a bike computer app, to the extent that I can’t even think what the main competitor is (strava constantly which is pushing annoying notifications about other people’s rides?)

  7. Andri Feldmann

    Hi Ray, and everyone else!
    Full disclosure I run the Swinco Performance Lab in Zürich and distribute Moxy in Europe. I just wanted to add some very simple insight as to how I look at Moxy, which may also help Jeff a little. In my opinion there are two basic questions that need to be anwesered to condsider Moxy a viable and even revolutionary product for anaylsis, but also very importantly training monitoring.

    1. Does NIRS technology and thereby Moxy work? Does it measure what it is supposed to measure?
    2. If Moxy does measures change in muscle oxygenation, is a) muscle oxyenation or b) change or balance of muscle oxygenation an important factor in perfromance?

    Question number 2 is in my opinion farily straigth forward considring contemporary exercise physiology, so yes (this can of course be discussed further). Which means we are only left with question 1, and the vast amoiunt of literature on NIRS.

    Saying yes to both questions really leaves us in a position where we now have a tool like no other that is physiologcial relevant, can be used to assess local and systemic changes, and most importantly is not bound to a laboratory setting…..I apologize, I pressed enter by accident and hopefully didnt leave to many spelling mistakes (didn’t read through my post yes). Nonetheless, I believe my point is fairly clear, and if any one has any questions or wants to discuss my point further I am also available per email: a.feldmann@swinco.ch.

    Thanks again Ray, and thanks for everyone else’s time!

    (Edited by Ray to just stick the two split comments together in one post, no change to content)

  8. Ruud

    Hi Ray, nice review! You should ask Moxy to also give you a picture with the zones for your test like the example picture you show. I am looking at your results but the pattern looks quite different than the example zone picture. Where would they set the bounderies for your zones in that respect?

    • Feldmann Juerg

      Ruud, I assume you are Dutch and I like that as my first great NIRS equipment was a Dutch product from Artinis ( Portamon) It is a great equipment but slightly more expensive. We did hundreds of assessments in all different sports and activities and diseases and learned the basic limitation but as well advantages of NIRS.
      To your interesting ” Zoning ” we name it intensity idea.
      If Ray allows us we can show on the MOXY forum his whole interpretation handout he got with SmO2 and tHb datas as well as discussion into details why we think he has some specific limitations he could improve for overall improvement..

  9. Feldmann Juerg

    Disclosure here as well and all in Swenglish ( Swiss and english ). I work since over 1/4 century together wiht my son on the idea to have a “BIO watch ” for my patients and athletes.
    Dream watch :
    HR , RF ( respiratory frequency ) and oxygenation and delivery information so in NIRS terminology SmO2 ( trend of muscle oxygenation ) and tHb as a trend indication of local blood flow.
    So here we are now in the application and the affordabilty of NIRS and integration of other bio marker. Combine this in some sport with performance and we have the ability for physiological individualized rehabilitation and training ideas.. You can now plan intervals for any sport, you now have duration of load , duration of rest in between loads as well as set numbers of repetition very individually.
    As well you can now do strenght workouts and see, whether you have a still available delivery of O2 but as well get rid of H + situation ( compression load ) versus inflow gretat and no outflow so veneous occlusion load with all the potential effects and last but not least no inflow no outflow so simply local energy use..
    Than we can look at assessments like in Rays case, whether we get some indication of limiters in his performance.
    Example .
    If the respiration may have a limitation than we have a specific local and systemic reaction and can there for create training intensities accordingly to our goal settings.
    This as a simple start . Ray did a very nice job showing the quality of todays affordable NIRS equipment and we did a very poor job and have to improve to bring physiologcilal ideas over to the people on the road and in the field. So I look forward to critical and fair feedbacks so we can improve into this new area of phsyiologcial biomarkers.

  10. Juerg and Andri Feldmann put together their detailed analysis of Ray’s data including the zoning and a bunch of background on their thinking. Here’s a link to it.

    Link to Analysis

  11. Ruud

    Great Roger to see that analysis. It’s I think the way to go if you want this technique to spread more: give examples, and give reasoning behind the things you see. Can’t wait to try mine and improve training (Andri had sent it Monday I hope ;)

    • Feldmann Juerg

      Ruud , here a challange i like to try.
      As soon you make any datacollection sent my the csv donwload file and we will discuss what we see with all the risks of being wrong or right so you and other can see, how much fun it is to work with physiological feedbacks.
      If you run a 5/1/5 give me a mail and we set up the possible intensities and if you make a RIP or SIP as well. cheers Juerg
      Check once in a while the moxy forum and you can see the interesting discussion we have on different cases from ice hcokey to downhill skiing to figure skating to strenght wokrouts to cross country skiing to name some of the differetnt activitis we use for MOXY applications Check the great work golden cheetah is doing with intergation of NIRS information . They are amazing fast howo they apply this..

  12. Ruud

    Great Juerg!! TNX very much I will do that!

  13. Mark Liversedge

    Hi Ray,

    I’ve been wearing one on most rides. Its a minor faff, and will be much easier when Garmin and co. support the muscle oxygen profile.

    The hard part is working out what to do with the data once you’ve collected it !!

    It will be interesting to track this as there are lots of scientific articles that provide ideas about tracking mitochondria capacity, arterial/venous flow, limiters, recovery rates and finding key markers like LT1/LT2 (aka BSX).

    A simple start might be to turn it into yet another stress metric for the CV system.



    PS: you definitely got suckered doing that test without a fan !!!

    • Feldmann Juerg

      Mark, here a suggestion. Next time you make for example a classical interval workout , sent me the following datas as a csv file.
      MOXY donwload so we have SmO2 and tHb , your load and unload wattage info and your HR. Nice as well would be the so called ” aerobic and anaerobic ” metrics.
      Than we can show closer and can show you from our side , how we look at the info in all different sports during a workout and or if you make a classical step test regular that is an other option . or you can make a 5/1/5 and we give you based on your max watt or FTP a trend information on the steps you can try. We tana can discuss it on the forum. Cheers Juerg

  14. Eli

    Would have been interesting to have the sensor on the calf which is where bsx is measuring from

    • Feldmann Juerg

      Eli you make a good point. We have over the last 10 years tested many athletes with multiple NIRS placing and now as we can afford as many MOXY’s on one athelete as we have space we have or we do this in every single assessment . Before we had the max of 2 great portamon but that was a lot of money and when combined with Physio flow plus VO2 equipment we had a 75 ‘000 $ test object . Now we can easy move left and rigth leg and left and rigth arm and even left and rigth hamstrings as we did with cross country skiers to learn and understand shfifts energy ( O2 ) during activity and changes of t for exampel running style ( from forefoot to heel like it happens in off road running all the time ).
      Here a link you can see some of the crazy ideas to help us understand more or a little bit better. link to forum.moxymonitor.com

  15. david n

    I don’t know if I missed it – but would it be possible to determine the aerobic & anaerobic threshold with the moxy? And is the software also suitable for runners?

    • Andri Feldmann

      I would argue that aerobic and anaerobic threshold does not exist in the traditional usage of the terminology. What Moxy does is reflect a balance between oxygen supply and oxygen utilization in the muscles, and it does this in a monitoring fashion- continuously and non-invasively with direct feedback.

      Now to consider the point of aerobic or anaerobic- regardless of physiological view- if for example you want to discuss classical terminology like anaerobic or aerobic threshold and consider these thresholds to be determined by some kind of blood lactate accumulation you need to ask yourself why does lactate accumulate of even more importantly why do we measure lactate and then give this parameter a value to determine some kind of threshold. The reason we measure lactate is to find out oxygen availability (supply and usage) in the muscle which may or may not result in blood lactate accumulation. So, as I am sure you followed, Moxy is actually a much director measurement than blood lactate as it measures what blood lactate hopes to measure = balance between oxygen supply and oxygen utilization.

    • Feldmann Juerg

      I can’t argue against this statement offered here by Andri and most of the readers know that the discussion is on since the 1985 ( Brooks ) when we learned , that lactate production due to hypoxia or anoxia is rather the exception than the rule. Newer studies by Connett et all as well as Richardson and Suhlman even show the option to have a serious discussion about the classical idea of ATP – Cr.P – Glucose- aerobic supply.time line.
      The interesting part of NIRS is the extremly nice picture live how even in extreme hard strength workouts SmO2 drops instantly and immedately asks the question how come that we see an imediate use Of O2 despite what we learned in school ?
      For people who like to use lactate threshold ( question is which threshold the one from Simons or Hollman or Hettinger or 45 degrees or Liesen or mader or 1 mmol increase but with what step lengtht ) But if you look for a trend in lactate and compared it with SmO2 or HHb or O2Hb you for sure will have a connection as O2 and lactate are closely link due to the fact that both are needed energy sources for activity.
      . What we see is by using 4 or more moxy’s on the same athlete , that the ( some people call it BP break point ) in the SmO2 or HHb or O2Hb values are not all the same if comparing for example left and righr or we look at calf , quadriceps and hamstrings on the same person. The trend can be close but the reactions very different. Here again one short link where you see exampels of crosscountry sking erg work bike wattage trainer and runing on both calfs.
      link to forum.moxymonitor.com

    • Feldmann Juerg

      David , here a short add on to your question.
      MOXY is a NIRS equipment , meaning that you can use it and measure SmO2 and tHb anywhere, where you have a muscels to fix it on and for any sport any activitiy. There is no limit so you can use it on as many peopele as you like and or indoors ou doors for swimming assessment ( we have some top canadian swimmers using it for assessments as well for sports like rock climibing on fore arm reactions or any ideas you may come up with. It is what it is , it assesses trends in O2 uitlization and delivery and tells you the trend in blood flow in the tested areas and this all live on a big screen in a climbing center and spectators can start to try to predict , when the climber will let go by looking at the trends. Same in or during ice hockey games you can as a coach see, which player should come out , which one is not recoverd yet and which one is systmically running into problems any many more info we can share in this fun new equipment ( not really new but now affordable ).

    • david n

      Dear Andri & Jürg

      Thanks for your detailed replies! The obvious questions is, whether someone, who has not a background in sports science, is capable of analysing the results and thus can make the right decisions in his/her training? (I assume that the e-books found on the moxy site can help the user to deduce such things).


    • Feldmann Juerg

      David, you make a good point. The main problem is US , we have to be better in making it easy to understand with the big task to not loosing the fundamental changes NIRS can give in sport as well as how to change traditional classical ideas in physiology.
      The development of new technolgy fast creates many nice questions about classical ideas.
      Example is lactate as a fuel rather than an ugly reasons of fatigue and so on.
      Discussion and people like you can help us to try to get it into the main stream thinking and using process.
      I run a High school program here locally and it seems the openness of the students to ask questions really makes it easy to introduce and use MOXY /NIRS in every workout we do.
      You really have 2 main informations.
      1. SmO2 which gives us feedback on O2 utilization or better bioavailablity.
      In general SmO2 increases when we deliver more than we use or we reduce the utilization before we reduce delivery at the intensity we move. It is stable if we have delivery and utilization in balance. It drops , whne we use at that moment more thnba we can deliver.. Like in a start situation of a strengt workout when HR ( cardiac out put ) for example ise not delivering but I need the O2 to keep activity going..
      2. tHb is the interesting trend information in how we deliver the blood.
      . a) free flow
      b) reduction due to muscle compresssion, reduced out flwo (venous Occlusion ) or no flow ( Arterial occlusion)
      If you now combine both you have basically 3 – 6 options as very common options and anybody who is doing sport and is lookig at the MOXY feedback live on a screen or on a watch can very fast understand what he is doing with O2 and energy situation.
      There are some specific cases but even this cases you can create as you play and you are ready to go. It is just somewhat thinking outside the BOX for a few days and try to avoid pushing NIRS info in a classical theory which may have to be reviewed rather earlier than later.
      So one of our main challanges is the traditional thinking we all are stuck in. The fact that we see with NIRS the drop in SmO2 immediatly even in strength workouts. ( see mowy forum strenght ( link to forum.moxymonitor.com )

      Let’s make a simple straigth forward example.
      a) if we now mostly accept, that lactate is a very important substance to shuttle energy and to help to buffer acidic situation as well as being used as important energy in sepcific situation as well as always prodcued ( so no such thing like alacticid) than one of the interesting questions comes up:
      Why do we have to cool down.
      What was the traditional answer.
      secnd part in this direction is .If lactate is that great of a fuel, why would we have to make a zoning where we have to “tolerate ” lactate?
      Now this are not attack against lactate users but open questions , as more as I was the first who brought many many years back point of care lactate analyzer to north america from Boheringer Mannheim ( accusport ) and than with Fact- Canada we had and still is the only FDA approved hand held lactate analyzer the lactate Pro. So lactate was my gospel as I was brought up in the and 4 mmol lactate world with G Mader, Hoolmann /Hettinger/ Liesen / Simon Stegemann , Tegtbour and Browmann and many more. Hard when you work a 1/4 century with this to question all this ideas and try to see, where I went wrong. Many great studies help to open the mind for further develeppment. We where not really wrong we simply where not able to look at informations we can look now with better and nicer equipment.

  16. Powell still rocking the Sony active. You’d think another good small phone would of come out in the last 3 years, but no.

    • H M

      Just replaced my sony active with an Xperia E3 – £100 with native ANT+ (and on KitKat) unfortunately not waterproof but I reckon I can switch back to the active if the weather looks rubbish….

  17. Gonzalo


    Do you support Apple products?

    • Hi Gonzalo,

      We currently have a couple of ways to use Moxy with Apple products
      1) If you have the ANT+ adapter for your iPhone or iPad, you can use the Moxy in the Speed and Cadence mode and pair to it with many of the cycling apps out there.
      2) You can use the Moxy with the Wasp from North Pole Engineering and use it with their Wasp Utility on an iPad.

      In the near future, there will be another option. Golden Cheetah is adding the capability to import Moxy data. It will import .FIT or .CSV files, record the ANT+ data, and download data from the sensor via the USB cable. This should be out in early 2015.

      We plan to add BTLE capability at some point in the future and have a dual mode device but we don’t have a timeline for that.

  18. Feldmann Juerg

    If readers are interested here a short part of DC’s comment:

    “Now that’s much easier to see. You can see my muscle oxygen level (%) is steadily going down, but it’s my final incomplete attempt that you really see it drop significantly towards the end of that set. It’s this specific drop that they’re really looking for in the test. ”

    I am not sure where we got this message, as it is NOT at all what we look for.
    Short here.
    1. We look at SmO2 trend over the whole assessment ( not test ) and we look at trends in the rest one minute period.
    This is the information NIRS gives us towards O2 utilization and O2 recovery.
    This is half of the picture as O2 has to be delivered as well or may not be used due to lack of O2 bioavailability ( respiration can create a problem with CO2 and O2 disscurve shift.)
    So for delivery we look at tHb ( trend or indication of blood flow or blood volume ) Now you combine both and you can see, what may limit utilization and or what may limit delivery and this is what causes the reactions.
    The last unfinsihed step on this assessment has minimal information other thana sign great utilization as SmO2 drops due to most likely delivery problems,.
    . If readers are interested come back on the http://www.moxyforum for questions.
    Thanks for thegreat help here to start a discussion on a great future of simple bio marker tools.

  19. Feldmann Juerg

    H aha DC I like your answer. I know that state. in fact I have even additional advantages to your state. I am getting older so I ” know” everything, but I can’t remember it at all. Thanks for the feedback Juerg

  20. Feldmann Juerg

    Hallo DC. I have, thanks to your blog here some emails from people interested in explaining from our point of view what you did.
    I will not do that as thsis are your personal datas with the exception that you allow us to use your info from the MOXY datas. If yes I will do it on our MOXY fourm If no that is perfectly great as well. Cheers Juerg

  21. Feldmann Juerg

    DC I can do both for sure I am just not sure, how I can shows graphs on your forum here so need some help as I am really bad in technology lihe this stuff.

  22. Víctor

    If you want to see another case of the use of Moxy with another wareable, WIMU (a type of inertial measure unit), check the link below.
    link to blog.realtracksystems.com
    I was wearing 2 moxys placed in the same position in each quadriceps; to study how each leg works while climbing with a mountain bike.

    I believe this information can be interesting for people that want to see a practical case of Moxy working and want to analyze SmO2 and ThB synchronized with other parameter (in that session, cadence sensor, heart rate, GPS and cinematic parameters.

    This particular device (WIMU) allows me to synchronized with video, so all data shown in the video correspond to the exact frame of the film. Hope you like it.

  23. steve

    I’m just not getting the benefit to looking strictly at muscle oxygen levels.

    To me, the benefit of knowing my LT and FTP is that I can set up workouts in zones that I can (and are willing) to do. FTP by it’s very definition is the hardest effort I can go for an hour. Likewise, LT is going to show me the pace/power point for where it’s no longer a sustainable effort. There is nothing “magical” about these values, other than I know if I try to do a 1 hour workout at a level higher than my FTP there is a good chance I will fail, and more importantly it will mentally beat me down. At the end of the day, the “best” workout is the one you actually do, rather than the one that looks good on paper but you fail or lose your motivation or just don’t want to do.

    So, what advantage would setting up workouts, based solely around muscle oxygenation levels give?

    • Hi Steve,

      Just a quick overview. There are 3 major groups of ways that muscle oxygen monitoring can be used to help athletes. 1) Assessments, 2) Guide Training, and 3) Optimize Competition

      Assessments with muscle oxygenation are aimed at finding what physiologic system is limiting performance and at what intensities those limitations kick in. Knowing the intensity of your lactate threshold can be helpful, but it can be even more helpful to know if it’s a supply or delivery limitation or even further if it’s a cardiac, respiratory, or muscular limitation. Cardiac can show up as slow recovery, muscular can show up as steady rising THb, respiratory can show up as high SmO2 even at high intensity. These types of insights can be inferred from muscle oxygen information more readily than from VO2max or blood lactate tests.

      One application of guiding training is for interval training. Do the high intensity until you reach the low plateau, rest until you recover, then repeat until you can’t reach the low plateau (fatigue causing reduced muscle fiber recruitment) or until you can’t recover to your baseline.

      The competition applications are for things like identifying when a hockey shift is ready for a rest or when the guys on the bench have recovered to a point that they’re ready to go again. We have people looking at using the data to modify cycling energy expenditure models in real time.

  24. Mario

    The Moxy connect app is since 2 days available for download in the Connect IQ store.
    link to apps.garmin.com

  25. Aaron

    For anyone with a Moxy looking for more post-workout analysis options – I’m happy to say both the SportTracks PC app and online .mobi app now support the blood sensor data collected from Moxy.

    • Aaron, I am very interested as a Moxy user, but unfamiliar with SportTracks.
      Any possibility you might happen to know and have the time to elaborate
      – what kind of analysis options?
      – does it support multiple Moxys used simultaneously?
      – can it automatically sync the imported Moxy data?
      – any support for live recording and display of multiple Moxys?

  26. Roger Schmitz really does a great job at MOXY
    Runalyze is importing (from fit-files) and showing those data (and support up to two sensors).
    We are open to your ideas to do a better post-workout analysis with this kind of data. Tell us what you need :) (via mail or forum at runalyze.com)

  27. Sven-Erik

    How is Moxy ’performing’ when compared with Humon (humon.io)?

  28. Eli

    Looks like Moxy finally refreshed their hardware: link to my.moxymonitor.com