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{{DISPLAYTITLE:BSX Lactate Threshold Monitor}}
BSX is a simple, easy to use device that estimates your [[Lactate Threshold]] (but its results may not be correct.) You just wear the BSX monitor in a custom calf compression sleeve that it comes with, along with the BSX app on your phone, while running on a treadmill. The BSX app tells you what pace to run at, which increases every 3 minutes until you can't continue, at which point it tells you your [[Lactate Threshold]] pace. Sadly, while the BSX simple and easy to use, the results are rather dubious and it's unclear to me if it does a better job than simply using an estimate of your 10K race pace. (Important: BSX has announced a second generation of their sensor and I will retest once that becomes available.) {| class="wikitable" |- valign="top"|[[File:BSX and Moxy1.jpg|none|thumb|x300px|The BSX sensor on the left with the Moxy sensor on the right. The BSX has no buttons, inputs or display, though you can reset it with a magnet. ]]|[[File:BSX and Moxy2.jpg|none|thumb|x300px|A view of the BSX and Moxy showing the infrared emitters and detectors.]]|[[File:BSX Moxy Test.JPG|none|thumb|x300px|Here's my setup for testing the BSX & Moxy. I attached both sensors to my calfs, putting the Moxy in the same position as the BSX. I linked the Heart Rate strap to the BSX (or attempted to, repeatedly), to my watch, and to Live Recording software on the PC (initially SportTracks, then [http://www.goldencheetah.org/ Golden Cheetah].) I used the BSX app on my iPhone and linked the Moxy to the live recording and my watch.]]|}
=How to use the BSX Lactate Threshold Monitor=
The BSX is remarkably simple to use, especially when compared with other ways of estimating [[Lactate Threshold]]. You'll need the BSX, its calf compression sleeve, an iOS or Android device, and a treadmill.
* Once you've reached voluntary exhaustion, stop the treadmill and the app
* The BSX app will then tell you your Lactate Threshold pace.
{| class="wikitable"
|- valign="top"
|[[File:BSX and Moxy.JPG|none|thumb|x300px|The BSX sensor in its calf compression sleeve. (The Moxy has to be taped on.)]]
|[[File:BSX1.jpg|none|thumb|x300px|The dashboard view of the BSX app, showing previous results.]]
|[[File:BSX2.jpg|none|thumb|x300px|You have to input your conversational and 10K pace (your 10K pace is an estimate of your Lactate Threshold.)]]
|[[File:BSX3.jpg|none|thumb|x300px|The app shows you the paces you'll be running at.]]
|- valign="top"
|[[File:BSX4.jpg|none|thumb|x300px|You get a display of the pace to run at, along with the time left in this stage. You can see your Heart Rate if the BSX has managed to link to your Ant+ heart rate monitor (I only got this to work once). You'll also see your SmO<sub>2</sub>, but for me it didn't bear any resemblance to reality.]]
|[[File:BSX5.jpg|none|thumb|x300px|When you're done the BSX app shows you what it thinks your Lactate Threshold is, along with other training paces.]]
|[[File:BSX Failed.PNG|thumb|x300px|If you managed to get your Heart Rate monitor to pair with the BSX at the start, then you can get this message saying it lost contact and your test failed.]]
|}
==An Example Test==
Here's a video of a test I did with the BSX. I sped up the 30 minute test so it lasts less than two minutes. Notice that my SmO2 says remarkably stable throughout the test.<br/>
<html><iframe width="560" height="315" src="https://www.youtube.com/embed/dIlDr3kayf0" frameborder="0" allowfullscreen></iframe></html><br/>
[[File:Moxy Test 20150823 0825.jpg|none|thumb|800px|Here is the Moxy data from the same test, showing a clear decline in SmO<sub>2</sub>, which is what you'd expect. This is in stark contrast to the BSX display.]]
=Why Measure Lactate Threshold=
The obvious question is why do you want to know your Lactate Threshold. There are several possible reasons.
=Advantages of the BSX=
* '''Simplicity'''. The BSX is vastly simpler than other methods of estimating or measuring your Lactate Threshold. There are no blood draws that accompany traditional tests, or the need to perform multiple runs on multiple days as required by the gold standards MLSS test. In addition, the BSX gives a clear and unambiguous indication of your Lactate Threshold without need for any interpretation.
=ConsConcerns with the BSX=
* '''Validity'''. While the BSX gives a clear and unambiguous result, it may not be correct. See "BSX Validity" below for a list of concerns.
* '''Single Protocol'''. The BSX app supports a single protocol that uses a incremental load test with 3 minute stages. If you want to do any other test protocol, such as longer stages or something closer to the MLSS protocol, you can't.
* Matt completed a single test with the BSX at their facilities. Matt's review shows a plot from the BSX software that is not normally available to the end user, showing time against a relative concentration. This is intriguing, and I have similar plot from BSX for a couple of my tests. However, BSX wouldn't tell me what the substance was that they were plotting as "relative concentration". If you look at the chart on Matt's site, you'll see what is probably the raw data in red, showing a huge amount of noise, an orange line that appears to be a smoothed version, then a simple green line that is further smoothed. This is all very intriguing, but equally unclear. As an aside, Matt includes a blood lactate plot he had performed a few years back, which would not have a Lactate Threshold based on the criteria BSX uses (1+1 mmol/l rise). That's slightly ironic, but it highlights the problem with their blood testing methodology. You can read Matt's review at [http://triathletesdiary.com/blog-2/entry/general-blog-posts/playing-with-the-worlds-first-wearable-lactate-threshold-testing-device-from-bsx-athletics.html http://triathletesdiary.com/blog-2/entry/general-blog-posts/playing-with-the-worlds-first-wearable-lactate-threshold-testing-device-from-bsx-athletics.html] and was published August 2015.
* Ray also completed a single test, and his write up includes the chart of blood lactate levels as well as some different charts from the BSX software. For the test Ray estimated his 10K pace as 6:05 min/mile pace, and the BSX indicated a Lactate Threshold pace of 6:03 min/mile, with the BSX blood test showing 5:42 min/mile. Ray's blog also includes a vaguely similar plot to the one Matt includes, showing noisy data in red. This chart is simply marked "estimated" on the Y axis and has a different scale with no units. This chart looks like a visual estimation of the breakpoint in the muscle oxygenation, something that other researchers have used. The review also includes some charts of probability, which is intriguing, but hard to interpret. You can read Ray's write up at [http://www.dcrainmaker.com/2014/09/bloodless-lactate-threshold.html http://www.dcrainmaker.com/2014/09/bloodless-lactate-threshold.html]
* Another set of reviews that BSX did not mention were performed by Gabriel Hernando of zitasport.com. Gabriel has written five articles about his experiences with BSX, mostly covering the difficulty in getting it to work. Gabriel found that the BSX gave a Lactate Threshold that compared well with his Functional Power Test from cycling. You can read Gabriel reviews at [http://blog.zitasport.com/category/crowdfunding/bsx-insight/ http://blog.zitasport.com/category/crowdfunding/bsx-insight/] (this is in Spanish, but Google can translate it reasonably well.)=BSX Gen 2=BSX has announced Gen 2 of their product, with the following features:* improved ANT+ and BLE connectivity * real-time muscle oxygenation recording * improved graphs and overhauled design experience * automated KICKR integration (during endurance tests) * Full download of all workout files * ANT+ broadcasting to watches and head units I will test the new generation when it becomes available (target October 2015). The Gen 2 product will be available at a discount to those who purchased the original device.