Fatigue Detection Through Thermography: A Real Case.

In this article, we present a real case study by ThermoHuman for fatigue detection. Are we individualizing recovery strategies? How can we assess it? We provide a practical application.

Fatigue is necessary for post-exercise adaptations, but excessive fatigue due to inadequate recovery or recovery strategies can lead to poor performance and increase the risk of injuries and illnesses. Professionals often wonder what the best recovery methods are to restore physiological and psychological homeostasis. Some, like sleep, nutrition, and hydration, are indisputable, but other therapies and applications such as cryotherapy, sauna, or contrasts raise doubts about their optimal timing for application.

This debate has gained interest due to recent publications (such as this one by Robin Thorpe) that emphasize the importance of identifying the type of fatigue (as there can be two: one more structural and another more internal) to individualize the most suitable recovery strategy.

Fatigue Detection with Thermography.

Thanks to thermography, we can measure internal load and physiological processes related to fatigue in athletes. As we discussed in another article on our blog, skin temperature can be related to the type of fatigue and how thermal means can be used to accelerate recovery.

Therefore, identifying the thermal response after competition based on an individualized thermal profile allows for the selection of the best recovery strategies. In broad terms, we can identify three trends in athletes’ thermal profiles:

• Hyperthermic: when the subject’s overall temperature increases.
• Hypothermic: when the overall temperature decreases.
• Neutral pattern: no significant variation in their historical thermal data.

For this purpose, the ThermoHuman software offers a metric called TSI (Thermal Status Index) that analyzes the overall coefficient of variation for each athlete over time to evaluate significant global trends after competing or experiencing high training loads.

Let’s see this with a practical example (Figure 1) with a professional team, where we find athletes with different post-competition thermal profiles, some with a hot tendency, others with a cooler profile, and others neutral.

Figure 1. Different thermal responses of athletes: example from a team.

Should they all follow the same recovery strategy? Or would it be better to group them based on their thermal profile? With ThermoHuman software, this is possible through tracking and individualization of thermal profiles. One metric we can use to identify this is through the coefficient of variation, which considers thermal trends independent of bilateral regions over time, using historical average temperature and standard deviation (you can find detailed metrics here).

Different Recovery Strategies Based on Thermographic Data

As we have explained in previous posts, thanks to objective thermographic assessment, we can improve recovery by selecting different strategies. We present a practical framework to enhance recovery according to Thorpe (2021):

This framework aligns with the idea that a hypothermic trend may be related to metabolic fatigue, while a hyperthermic trend is more linked to structural damage. Therefore, we suggest that infrared thermography could be useful in identifying the type of fatigue and adapting post-exercise recovery strategies on an individualized basis. From ThermoHuman, we offer a practical framework based on thermal response.

Conclusions

Thermography emerges as a promising tool for assessing fatigue in athletes and customizing recovery strategies. The variability in athletes’ thermal profiles suggests the need to adapt recovery strategies based on their individual responses, which can contribute to improving performance and preventing injuries. Infrared thermography and ThermoHuman software provide objective metrics (such as TSI) to identify the type of fatigue and guide recovery decisions more effectively.

References

Kellmann M, Bertollo M, Bosquet L, Brink M, Coutts AJ, Duffield R, Erlacher D, Halson SL, Hecksteden A, Heidari J, Kallus KW, Meeusen R, Mujika I, Robazza C, Skorski S, Venter R, 

Beckmann J. Recovery and Performance in Sport: Consensus Statement. Int J Sports Physiol Perform. 2018 Feb 1;13(2):240-245.

Thorpe, R. T., Atkinson, G., Drust, B., and Gregson, W. (2017). Monitoring fatigue status in elite team sport athletes: implications for practice. Int. J. Sports Physiol. Perform. 12, 1–25. doi: 10.1123/ijspp.2016-0434

Thorpe RT (2021) Post-exercise Recovery: Cooling and Heating, a Periodized Approach. Front. Sports Act. Living 3:707503. doi: 10.3389/fspor.2021.707503