Coaches should always define training parameters based on the individual assessment of the athlete. Ideally, this assessment should not be based solely on the trainer’s gut feeling, but should be based on performance diagnostic data.
Sports science has been doing research with near infrared spectroscopy (NIRS) for quite some time and various athletes also use this technology in their everyday training and competition. However, until some Norwegian top triathletes increasingly spread photos in the social media in recent months, showing how they train with Moxy devices, the general public in the triathlon scene didn’t became aware of the NIRS technology. The illustrations in this article were taken from the respective web presence of the athletes on the Instagram platform.
Although have seen it for some times, most people still don’t know much about how Moxy works. In addition, they often lack the knowledge to assess the potential of these devices. This contribution should help to better understand one of the latest technologies on which this Norwegian training group relies.
The “Muscle Oxygen Monitor” (MOXY)
The Moxy Monitor is a compact, waterproof and portable wearable. This device measures non-invasive and continuous among other things the oxygen saturation in the muscle. The real-time feedback allows immediate, fact-based adjustments of the training intensity.
What Moxy measures
Moxy measures local muscle oxygen saturation (SmO2) and total hemoglobin levels using NIRS technology. These data are stored on the one hand, but are also transmitted wirelessly and displayed directly on a sports watch or on an associated software. This allows in real-time to see what is happening inside an athlete’s muscle.
For coaches and athletes the SmO2 is interesting first and foremost. It describes the proportion of oxygen-saturated haemoglobin and myoglobin in muscle tissue. The SmO2 is given as a percentage value from 0 to 100. A value of 0 would correspond to total muscle deoxygenation. Put simply, SmO2 represents the balance between oxygen supply and consumption in the tissues around the capillaries. If more oxygen is needed than is delivered, the oxygen saturation in the muscle decreases. The validity of the NIRS technology for the evaluation of muscle oxygenation during physical activity was demonstrated by Mancini et al. (1994). Crum et al. (2017) see the reliability of the SmO2 measurements of Moxy as given above all at low to moderate intensities and state that at higher intensities greater fluctuations of these measurements may occur.
Moxy in praxis
In endurance sports, Moxy can be used in particular for physiological training intensity control and recovery monitoring. The SmO2 includes external factors such as the athlete’s temperature or fatigue, which makes the expert use of the tool particularly effective. In this respect, the Moxy data also differ significantly from measured values such as speed or watts.
In acyclic sports, such as ice hockey, the Moxy data can be used to identify when an athlete is tired at a certain point and can’t maintain his performance. Conversely, it is also possible to see when the athlete has recovered sufficiently on the bench and is therefore ready to intervene in the game again.
In the ideal case, as practiced in the professional environment of Norwegian triathletes, the Moxy data are always interpreted in combination with other physiological parameters. This combined information can then be used to better evaluate athletes, design more effective workouts and consequently achieve more optimal results.
Optimization potential for Moxy
The penetration depth of the rays is limited. Therefore, Moxy can only provide data in the desired quality if the skin layer above the muscle is not too thick (< 12mm). In addition, scientific studies regarding training with Moxy are still very limited. At present, there are hardly any research efforts to link the concrete application of Moxy in training with resulting changes in performance. Furthermore the interpretation of the Moxy data requires a certain specialized knowledge. If the developers can present an easily understandable analysis of the data to interested athletes in the future, Moxy can appeal to a broader target group.
In the next blog post Andri Feldmann, who is intensively involved with Moxy, will give information about the use of Moxy.