Muscle injury has a multifactorial etiology where neuromuscular fatigue is one of the factors that most influence its incidence (Huygaerts et al. 2020). The control of fatigue and the physiological state of the tissues helps to monitor the fatigue and functional overload processes to which players are subjected during sports practice. To this end, thermography has demonstrated its usefulness in evaluating the physiology of skeletal muscle and its fatigue (Cortê et al. 2019; Gómez-Carmona et al. 2020).
Figure 1. Interactions between fatigue and hamstring activation and function (adapted from Huygaerts et al. 2020).
Authors such as Gabbett et al. (2016) have defined training loads, and above all, their imbalances in acute:chronic workload ratios (ACWR) as one of the factors responsible for the incidence of injuries. Other authors criticize Gabbett's work for being a unifactorial approach to the identification of soft tissue injury risk (de Rossi et al. 2022). Authors such as Impellizzeri et al. (2020) show a low predictive performance in its application to real scenarios, defending the idea that multiple sources of information collected in a machine learning screening process are needed for artificial intelligence to be able to evaluate the factors that make it possible to predict injuries.
In this aspect, thermography is one of the many tools that would contribute to this data pool for the prevention and prediction of injuries.
As seen in previous posts, there are multiple investigations, own and external, on the methodology of using thermography for injury prevention. In summary, thermography provides the team with information on the regions of interest that are prone to injury in sports (in this case, football), such as quadriceps, hamstrings and calves, so that through an alarm system generated by the thermal asymmetry metric, a decision can be made based on the temperature difference and the player's perception.
The classification of asymmetries makes relevant all those regions that exceed the difference between lateralities by 0.6 ºC and/or that have occurred repeatedly, so that a complementary treatment may be carried out.
The objective is to identify those regions with a potential risk of muscle injury and tackle the problem with an intervention that manages to return the body to a basal state and maintain it for at least the following two weeks.
As the results of studies in the reduction of approximately 60-70% of muscle injuries show, thermography seems to be an optimal strategy in order to reduce the prevalence of muscle injuries. These results are explained in detail in this publication.
In this case study (figure 2), a professional soccer player is presented, who on January 18 presents an asymmetry in the right hamstring of 0.58 ºC above the normative values for that region and for her individual profile. At that first moment, there are no concomitant discomforts.
Figure 2. Example of a professional soccer player, in which we see several thermography images analyzed, with their respective recommendations based on the result.
It is a region of special interest, since it is estimated that the hamstring region has one of the highest incidences, which has also not stopped increasing in recent years (Ekstrand et al. 2021). For this reason, the strategy of monitoring with more analysis the following days is taken. The next day, the evaluation shows a significant increase in thermal asymmetry in the region, together with a feeling of general fatigue and specifically a feeling of heaviness in the region. Therefore, it is suggested to adapt the load and carry out cushioning training to recover from fatigue.
In the following evaluation, the asymmetry has been reduced and it is recommended to carry out a follow-up until the temperature of the area is normalized and that it remains symmetrical in the following weeks, so at least follow-up is recommended.
From the ThermoHuman team, we value this case as an example of muscle injury prevention due to several factors:
Thermography helps us make decisions by reporting changes in the physiological state of body regions that, depending on the sports discipline, are more susceptible to injury.
Body temperature tends to maintain a balance that we detect through the metric of asymmetries and that will help us assess which regions lose their normality, both in general and at an individual level for each player.
Gabbett, T. The training-injury prevention paradox: Should athletes be training smarter and harder? Br. J. Sports Med. 2016, 50, 273–280
Impellizzeri, F.; Matthew, S.; Kempton, T.; Novak, A.; Coutts, A. Acute: Chronic Workload Ratio: Conceptual Issues and Fundamental Pitfalls. Int. J. Sports Physiol. Perform. 2020
Rossi, A., Pappalardo, L., & Cintia, P. (2022). A Narrative Review for a Machine Learning Application in Sports: An Example Based on Injury Forecasting in Soccer. Sports, 10(1), 5.
Côrte, A. C., Pedrinelli, A., Marttos, A., Souza, I. F. G., Grava, J., & José Hernandez, A. (2019). Infrared thermography study as a complementary method of screening and prevention of muscle injuries: pilot study. BMJ Open Sport & Exercise Medicine, 5(1), e000431. doi: 10.1136/bmjsem-2018-000431
Gómez-Carmona, P. M., Fernández-Cuevas, I., Sillero-Quintana, M., Arnáiz-Lastras, J., & Navandar, A. (2020). Infrared Thermography Protocol on Reducing the Incidence of Soccer Injuries. Journal of Sport Rehabilitation. doi: 10.1123/jsr.2019-0056
Huygaerts, S., Cos, F., Cohen, D. D., Calleja-González, J., Guitart, M., Blazevich, A. J., & Alcaraz, P. E. (2020). Mechanisms of hamstring strain injury: Interactions between fatigue, muscle activation and function. Sports, 8(5), 65.
Ekstrand, J., Spreco, A., Bengtsson, H., & Bahr, R. (2021). Injury rates decreased in men's professional football: an 18-year prospective cohort study of almost 12,000 injuries sustained during 1.8 million hours of play. British journal of sports medicine, 55(19), 1084-1091.
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ThermoHuman has had the support of the Funds of the European Union and the Community of Madrid through the Operational Programme on Youth Employment. Likewise, ThermoHuman within the framework of the Export Initiation Program of ICEX NEXT, had the support of ICEX and the co-financing of the European Regional Development Fund (ERDF).
Thermohuman has received funding from the Centre for the Development of Industrial Technology (CDTI), in participation with the European Regional Development Fund (ERDF), for the R+D activities involved in creating a new tool, based on thermography, for the prediction and prevention of rheumatoid arthritis. See project detail.
