One of the greatest challenges for coaches is maintaining their athletes' capacity to perform high-speed efforts. Speed is one of the physical qualities that deteriorates the most with age and detraining (Korhonen et al., 2009; Rittweger et al., 2008). Furthermore, it is intimately linked to the most decisive moments in team sports, whether scoring a goal or penetrating between lines to gain an advantageous position over the opponent (Faude et al., 2012; Haugen et al., 2014).

But what happens to the body when we train speed? Coaches suggest that, when faced with maximum speed demand stimuli, recovery and adaptation times will be elevated; in fact, a recovery period of 48–72 hours has been proposed following a speed session, depending on the applied dose (Mendiguchia et al., 2024). In addition, sprinting is closely related to hamstring injury mechanisms, especially during the late swing phase due to the high eccentric demand on the biceps femoris (van Dyk et al., 2020). However, dosed exposure to high-speed running can increase tissue tolerance and reduce injury risk, acting as a "vaccine" against these injuries (Mendiguchia et al., 2019; Malone et al., 2017).

All these data reinforce the need to understand how the body responds to this stimulus. What is known as "internal load" or "internal response" becomes highly relevant data for estimating the adaptation time required for each athlete when preparing for or recovering from competition with a high demand for these stimuli. That is where thermography—and consequently metrics related to skin temperature—can be of particular interest for measuring the impact of speed on each athlete's internal response.

To this end, we present evidence across three different approaches*:

1. What an isolated training session entails acutely and in the immediate hours following (up to 8 hours post-exercise);
2. What competition (in a team sport like football/soccer) entails when exceeding the threshold of high-speed running actions (meters above 21 km/h);
3. Finally, what types of speed training methods are going to be more specific.

*It is important to remember that in these approaches we predominantly measure the thermal response from a localized perspective—that is, the response of regions of interest (ROIs)—and not the global trend, which is what we typically measure when identifying post-match fatigue.

1. Effect During the First 8 Hours After Speed Training

To begin, we have the research by Fernández-Cuevas (Fernández-Cuevas, 2012), which analyzes in isolation what a classic speed training session entails (2 x 3 repetitions of 40 meters at maximum speed, with 3 minutes of recovery between repetitions and 6 minutes between sets), measured with thermography before, immediately after, and once every hour up to a maximum of 8 hours post-exercise.

The results show that immediately afterward, there is a drop in skin temperature caused, among other factors, by vasoconstriction toward target organs. Meanwhile, 8 hours following the training stimulus, body temperature returns to baseline. Therefore, the speed stimulus—unlike other modalities such as strength or endurance training (which induce an increase in skin temperature)—elicits a hypothermic response immediately post-exercise (Fernández-Cuevas, 2012).

2. High-Speed Running (HSR) During Football Competition

Second, we have the study by Escamilla-Galindo et al. (Escamilla-Galindo et al., 2025), which analyzes how high-intensity running values affect athletes after competition. The study established the median of efforts above 21 km/h (HSR, high-speed running) for a football squad to analyze how that threshold can alter the post-match response.

The findings showed that athletes with higher HSR tend to cool down or maintain their temperature, whereas those who perform lower volumes at that intensity warm up after matches, reaffirming the concept that the imposed stress exerts a central impact on athletes.

3. Specific Speed Training in Football

Finally, regarding the training methods analyzed by Arnaiz-Lastras (Arnaiz-Lastras J., 2017), it is relevant to note that they align with the results obtained by Fernández-Cuevas et al. (2012): shorter durations with higher intensity result in a cooling of the system, whereas longer durations with lower intensity increase the athletes' body temperature.

The evidence to date demonstrates that a speed-type stimulus, whether in training or competition, typically manifests as a decrease in skin temperature. Evidence also indicates that when the effort is more prolonged, with a greater mechanical component (such as changes of direction) or higher volume (distance or time), the cutaneous thermal response tends toward hyperthermia. Although further scientific evidence remains necessary, these data already allow practitioners, through thermography, to correlate hypothermic internal responses with exposure to high-speed tasks, enabling accurate measurement to better adjust workloads and recovery protocols.

References

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Rittweger J, di Prampero PE, Maffulli N, Narici MV. Sprint and endurance power and ageing: an analysis of master athletic world records. Proc Biol Sci. 2008;276(1657):683–689. doi:10.1098/rspb.2008.1319.

Faude O, Koch T, Meyer T. Straight sprinting is the most frequent action in goal situations in professional football. J Sports Sci. 2012;30(7):625–631. doi:10.1080/026401412.2012.665940.

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van Dyk N, Wangensteen A, Vermeulen R, Whiteley R, Witvrouw E. The mechanism of hamstring injuries: a systematic review. BMC Musculoskelet Disord. 2020;21:561. doi:10.1186/s12891-020-03658-8.

Mendiguchia J, Martinez-Ruiz E, Morin JB, Samozino P, Edouard P, Alcaraz PE, et al. Running fast: the cause, the cure and a vaccine. Br J Sports Med Blog. 2019 Mar 19.

Malone S, Roe M, Doran DA, Gabbett TJ, Collins K. High chronic training loads and exposure to brutal exercise periods are associated with increased risk of hamstring injury. J Sci Med Sport. 2017;20(12):1078–1083. doi:10.1016/j.jsams.2017.05.019.

Fernández-Cuevas I. Effect of endurance, speed and strength training on skin temperature measured by infrared thermography [doctoral thesis]. Madrid: Universidad Politécnica de Madrid; 2012.

Escamilla-Galindo VL, Vega-Ramos A, Felipe JL, Alonso-Callejo A, Fernandez-Cuevas I. Skin temperature as a marker of physical fitness profile: the impact of high-speed running in professional soccer players. Sports. 2025;13(12):443. doi:10.3390/sports13120443

Arnaiz-Lastras J. Monitoring the acute effects of recovery, training and competition on football player’s skin temperature with infrared thermography [doctoral thesis]. Madrid: Universidad Politécnica de Madrid; 2017. doi:10.20868/UPM.thesis.48734