Comparison

Train.Red APP vs XO

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Train.Red APP

This app monitors muscle oxygen saturation to provide real-time physiological insights for athletes and coaches. It helps optimize performance, track recovery, and analyze training data with actionable metrics.

Highlights
  • Muscle oxygen saturation monitoring
  • Real-time physiological insights
  • Performance and recovery tracking
  • Workout analysis and data export
  • Team/organization structure
  • Live data overlay
Read full description

About this app The official app for the Train.Red muscle oxygen sensors, the new metric for performance. To move, your muscles need energy. The most efficient way to get this energy requires oxygen. We measure the oxygen saturation in your muscles to help you improve. Not every athlete has a team of scientists helping them with their physiological data, we measure data from your muscle and translate this into useable insights, in real-time. - Monitor your physiological power and perform easy exercise tests as an endurance athlete. - Know when your muscle is fully recovered and ready for the next set when doing strength. What’s more? - Cloud functionality to allow workout analysis at home, even when you perform in the gym. - A Team/organisation structure that allows multiple athletes to use the sensors. - Actionable insights after your training or scientific analysis with access to raw data. - Live view with data overlay to match measured fatigue with movement patterns. - Muscle States, Protocols, Dashboard, Training Menu, Muscle Stress Score, and much more. How to start with Train.Red: Create a user profile and connect your sensor. No sensors yet? The Train.Red app requires the Train.Red sensors for full functionality (https://train.red/). Connected your FYER or PLUS? Nice, you are ready to BE AHEAD. What does Train.Red do for me: Whether you’re an athlete, coach, scientist, physio, or anyone involved in sport, Train.Red has something to offer you. Simply because your muscles play a key role in human movement. We track your muscle oxygenation, more specifically, the hemoglobin concentration changes. The Train.Red sensors measure: - SmO2, Muscle Oxygen Saturation (%) - O2Hb, Oxyhemoglobin (mM) - Hhb, Deoxyhemoglobin (mM) - Thb, Total hemoglobin (mM) - HbDiff, the Hemoglobin Difference (mM) If this sounds like Abracadabra, no worries. We display the oxygen saturation in your muscle live and use the other metrics to provide you with actionable insights in real-time. Our AI and advanced analysis options translate this data into 5 different muscle states showing you if your muscle is recovering, or approaching its limits. If this physiological data sounds familiar, perfect. We allow exporting your data to .csv or .fit files for an in-depth analysis of all your data. Every single training session is stored in our cloud and can be analyzed or exported afterward. How do I use Train.Red? The Train.Red sensor is a light-based wearable that you wear directly on your skin. You’re free to place the sensor anywhere on your body but know that this is a hyperlocal metric that will only tell you something about the exact location you place the sensor. We recommend wearing the sensor on a primary involved locomotor muscle, a place on your body that is active during the activity you’re performing. e.g. on your thigh during cycling or squats, the middle part of your upper leg during running, or on your lower arm during climbing. Of course, you are free to use more than one sensor! You can connect up to 4 sensors simultaneously and measure multiple areas at once. You’re not bound to this smartphone application. The Train.Red hardware is integrated into 3rd party apps allowing you to easily synchronise your data from multiple sources. Train.Red sensors can be connected to most Wahoo’s, Garmin’s, Suunto’s and several other devices. More information can be found on our website https://train.red/

About

XO

Features
Read full description

Using the XO-SOLE application, seamlessly connect to the XO-SOLE system to record, visualize, and store movement data directly to your insoles. Powered by XO-NANO's patented Smartfoam™ technology, XO-SOLE captures high-quality movement data without the limitations of traditional laboratory equipment. Whether you're conducting research in the lab or collecting data in real-world environments, XO-SOLE makes movement analysis more portable, efficient and accessible than ever before!

Screenshots

Train.Red APP4 screens
XO3 screens

Verdict

The call

The clearest difference is iOS requirement: Train.Red APP at 13.0 against XO's 15.0. On price, update cadence, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 3 weeks. The most recent releases landed on July 30, 2026 and September 6, 2026 respectively.

Scorecard1 real difference · 8 level
Train.Red APP versus XO: the parameters behind the verdict, then further details
ParameterTrain.Red APPXO
PriceFreeFree
Rating5.0 (1 ratings) — better—
Number of ratings1 — better—
Update frequencyEvery 3 weeksEvery 3 weeks
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS13.0 — better15.0
Further details — not scored
Size101 MB58 MB
Age rating4+12+
DeveloperTrain.Red B.V.XOnano Smartfoam

In-app purchases

None

Train.Red APP

No in-app purchases

None

XO

No in-app purchases

Questions

Is Train.Red APP free?
Train.Red APP is free to download, with no in-app purchases.
Is XO free?
XO is free to download, with no in-app purchases.
Do Train.Red APP or XO have ads?
Neither Train.Red APP nor XO shows ads.
Which is updated more often, Train.Red APP or XO?
Train.Red APP ships an update every 3 weeks, and XO every 3 weeks. Most recently, Train.Red APP was updated on July 30, 2026 and XO on September 6, 2026.

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