In sports, we monitor speed, volume, and heart rate, but often overlook the most trainable asset.

our muscles

Muscle Oxygen data can make you a better athlete

PUT physiology first

Fick equation (CO = VO2/AVO2diff)


Deliver O2 to the muscles and remove CO2 from the body.


Supply the muscles with the necessary oxygen and nutrients to perform the activity


O2 supply is crucial for optimal performance and preventing fatigue during exercise.

Learn muscle oxygen & your benefits

fastest sport test

Forget about masks and laboratories.
Here's how to perform the easiest fitness test, based on muscle oxgyen.

improve your training

Day in the life of an athlete.
Taking you through a muscle oxygen training diary with tips and tricks from professionals.

How muscles work

Why muscles need oxygen.
Deep dive into the physiology of your muscles' oxygen consumption.


Testing is an important part of the screening process:

  • It gives an accurate picture of fitness
  • An indication of appropriate starting intensities
  • A baseline for goal-setting
  • Assistance in group fitness recommendations


We made fitness testing easy


Select test


Test style




Guided test


ramp phase

From test to Training

Now transfer all this new information directly into our day to day training

Train.Red Sensor

Positioned on the upper leg

Zwift to control

As visualisation and a way to control the intensity

Train.Red APP

To guide you through the test

Typical training


What is your goal of the session?

This is essential for the athlete, aswell as the coach to improve.

Typical training day

warm up basics

Every trainings session, should start with a warming-up. During a warm-up it is important that your body is ready for the coming intensity.



A better warming-up, is the warming-up that increases the oxygenation in the muscle, without fatiguing the muscle.



Filip's warm-up protocol starts with a warmup, second part is the race
pace intense segment, aimed to elevate body temperature and enhance blood flow. Following up by a cooldown:

  • 10-minute easy spin at 140W,
  • three 2-minute bursts at 95%
  • 7-minute easy pedaling


the Science

A severe warm-up reduces mean-power output. The warm-up intesity and its effect on glycontic engery prdouction are imporatn to consider for e.g. Sprint Performance. More information on scientific level is available on our website.

Typical Training Day

Pacing and intensity

We know how to do an incremental test with the sensors, but you can use this exact same information during your workouts, in real time.

A traditional training program precribes output metrics or heartrate, but you can actually be more accurate with our physiological data.

Instead of 3x12 squats with 80kg or 3x20 mins at threshold power use your muscles to guide this load.

Pacing & Intensity


HowI’m personally using the Train.Red data, is for intensity control.

Aim at 15-20 hrs a week of training.

Polarized approach: 80% relatively easy and 20% hard.

Pacing and intensity

Breaking 2

Great example of how to use physiological data


Strength example pacing


Test results

Smart rest

Resting basics

Smart rest

Rest feature

Smart rest guide

Simple baseline test


warm up


Smart rest

Intro Physiology/SMO2


Intro Physiology/SMO2

Muscle Function

Intro Physiology/SMO2

Muscle Metabolism Energy systems

Intro Physiology/SMO2

Cardiovascular system

Intro Physiology/SMO2

NIRS explained

Intro Physiology/SMO2