The BSXinsight claims to measure two things: lactate threshold via a multi-step test, and real-time muscle oxygenation with data that can stream to a smartphone or a Garmin Edge computer.
After months of testing, I have found that the device has fascinating potential, but the lactate-threshold measurement isn’t entirely reliable and the muscle-oxygenation data, while novel, isn’t immediately actionable for training.
Also, the BSXinsight is so far ahead of the game that things like muscle oxygenation aren’t yet integrated into standard training protocols as sports scientists and cycling coaches work out what do do with the data. Although oxygenation fields exist in Today’s Plan training software and just added into a Garmin Edge software update in mid-March 2016, the BSXinsight is still closer to an experimental lab tool than a plug-and-play consumer product.
What is lactate threshold?
BSX uses two definitions: LT1 and LT2. BSX calls LT1 aerobic threshold, or the point at which exercise first produces a rise in blood lactate above a baseline.
It calls LT2 anaerobic threshold, which is closer to what most cyclists define as lactate threshold or functional threshold power. It is the point at which blood lactate rises steeply. Blood finger-prick tests will define this line as the point at which blood lactate rises by 1 mmol/L or more in two consecutive three-minute power-increase stages.
In practical terms, cycling coaches talk about FTP as the highest average power you can sustain for an hour.
How BSX measures lactate threshold
My experience with BSX lactate threshold tests
What is muscle oxygenation and how does BSXinsight measure it?
My experience with muscle-oxygenation measurement
Not yet a fluid consumer product
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