IMPROVE YOUR
Muscle Stamina
Stay in ideal training states with live Muscle O2 feedback and track progress with detailed post-session reports.
Muscle Efficiency
Balance aerobic and anaerobic energy to sustain medium-intensity efforts. Track critical power in real time, prevent early fatigue, and get recovery guidance for your next interval.
Muscle POWER
Push short, high-intensity bursts while tracking muscle oxygen in real time. See when you hit anaerobic limits and get recovery feedback to maximize your next effort.
You track speed, workload, and heart rate — but what about your muscles?
How Train.Red can help
For athletes, coaches, and fitness enthusiasts
Why Choose Train.Red?
Upgrade your training with the fastest Muscle Oxygen Sensors and our easy-to-use app.
Real-Time Data for 10+ sensors
Get real-time muscle performance insights with up to 22 units at 10 Hz, all day.
Fast Setup & easy Insights
No science degree needed—just actionable results
Advanced Technology
Backed by 20+ years of scientific research of our partner Artinis Medical Systems.
Seamless Integration & export
Track and sync data effortlessly across devices
Train.Red FYER
Our smartest and smallest Muscle Oxygen Sensor
Auto report feature
Discover a detailed muscle profile following a Train.Red threshold test. Uncover essential training insights for both athlete and trainer
Train.Red PLUS
The fastest and most advanced Muscle Oxygen Sensor
Train.Red APP 2.0
Get yours now on Google Android or Apple iOS
train.red 3rd party
Our system is integration in many other ecosystems. Click here to learn more
Over a decade ago, during my PhD at KU Leuven, I discovered NIRS—then bulky, expensive, and limited to altitude studies. Train.Red revolutionized it with simple, reliable, real-time muscle monitoring. Like a portable exercise lab, NIRS surpasses heart rate monitors, enabling non-invasive tracking over weeks. The Train.Red FYER and PLUS sensors are essential for coaches and athletes aiming for peak performance.
Visit WOD_SCIENCE
Over a decade ago, during my PhD at KU Leuven, I discovered NIRS—then bulky, expensive, and limited to altitude studies. Train.Red revolutionized it with simple, reliable, real-time muscle monitoring. Like a portable exercise lab, NIRS surpasses heart rate monitors, enabling non-invasive tracking over weeks. The Train.Red FYER and PLUS sensors are essential for coaches and athletes aiming for peak performance.
Visit WOD_SCIENCE
more EXPERTS IN THE FIELD
Roman Fomin
Mathieu Defontaine
Hidde Weersma
Elite HYROX Athlete & Human Movement Scientist
TRAIN.RED COMPATIBILITY
Want to integrate Train.Red into your already existing routine? We understand!
NEVER STOP LEARNING
our tech
Decades of science resulting in 20 grams of tech, allowing you to measure muscle oxygen.
Courses
"Data will talk to you, if you're willing to listen". Listen and learn how to use muscle oxygen data.
manual
Learn how to use the hardware,
the software/app or how sync with 3rd party platforms.
connect your sensor to the train.red app for all features
APP MANUAL
Muscle Oxygen Sensors
FREQUENTLY ASKED QUESTIONS
Do you have some more questions? Check the FAQ, or visit our support page to find out more.
What sensor is best for me?
You can compare our sensors on this page to ensure you make the right choice!
Do you ship internationally?
Yes, we do! We ship from the Netherlands, shipping cost depends on your location. We offer free shipping within Europe*.
For businesses and all other countries, costs are calculated automatically on the website.
How long will it take to get my order?
It depends on where you are. Orders processed here will take a few business days to arrive. Overseas deliveries can take anywhere from 2-14 days. Delivery details will be provided in your confirmation email.
What if the app crash after calibration?
If the app crashes after the 10-second calibration, it may be due to GPS not being enabled on your phone. GPS access is required for the app to function properly.
Solution:
- Ensure GPS is enabled on your phone before starting a session.
- When prompted for location permissions, grant access to the app.
- If the issue persists, manually enable GPS for the Train.Red app in your phone’s settings.
Why can't connect my sensor via Bluetooth?
If you've followed the recommended troubleshooting steps and your sensor still won't connect, check if other Bluetooth devices are interfering with the connection.
One common issue occurs with smartwatches. If a smartwatch is charging, it may automatically keep the sensor connected, even in standby mode, preventing your phone from establishing a connection.
Solution:
- Try disconnecting the charging cable from your smartwatch.
- If the issue persists, enable Airplane Mode on the smartwatch. This will prevent it from interfering with the Bluetooth connection.
- Once the smartwatch is in Airplane Mode, try reconnecting your sensor to the phone.
This should resolve the issue and allow your sensor to connect properly. If you continue to experience problems, please contact our support team.