Prevention of stress fractures in soccer players using thermography
Sports injuries, such as fractures, are characterized by a multifactorial etiology. One of the most relevant factors is the external load imposed on the tissue. With thermography we can assess how the tissues are thanks to the relationship between the temperature of a region and the use of that body area.
Thermography is a non-invasive tool that allows a fast assessment of the body regions of soccer players. In less than 30 seconds per player, it is possible to “map” the body regions and have an overview of the body areas that present thermal asymmetry.
The detection of body regions with thermal asymmetry is the methodology used by research that has shown a significant reduction in muscle injuries using thermography in soccer (Côrte et al. 2019; Gomez-Carmona et al. 2020). In addition, as indicated by the investigations of Escamilla-Galindo et al. (2022) and Vardasca et al. (2012), the body regions tend to a state of balance that is considered as normal. The analysis of 950 healthy athletes with the ThermoHuman protocol showed a mean symmetry between regions of 0.004 ºC (Escamilla-Galindo et al. 2022). Finally, the metric of thermal mean asymmetries is the most reliable to analyze the physiological change in body tissues (Formenti et al. 2018).
Thermography as a method to detect stress fractures
As we have already seen in another blog post, stress fractures can be detected by using thermography with a high sensitivity above 80% (Devereaux et al. 1984; Goodman et al. 1985), being the hyperthermic response the one that is related to the presence of this type of pathology. The scientific literature shows how the stress-strain curve can explain stress fractures by subjecting the bone to repeated stress (Bennell et al. 1996), relating this fact to hyperthermic findings in thermography.
Thermography is therefore postulated as a low-cost, fast and non-invasive technique to analyze if a body region is no longer normal and is beginning to generate thermal asymmetry. In a case of stress fracture, we usually find a hyperthermic asymmetry and it compromises the bone tissue. A region particularly susceptible to stress fractures in soccer players is the area of the fifth metatarsal.
As previously described, soccer stress fractures are a frequent, severe and common injury in high-performance sports (Sobhani et al. 2013), especially in sports with multiple jumps on hard ground, such as soccer (Okunuki et al. 2022; Matsuda et al. 2017). It occurs most frequently in long bones that receive a lot of impact from the lower limb, such as the metatarsals, calcaneus, or tibia (Finestone et al. 2011). In addition, training of greater intensity or duration than usual, for an unconditioned athlete, will pose a significant risk of suffering a stress fracture, since their osteoblasts will not respond to the demand for bone repair (Warden et al. 2014).
Therefore, analyzing soccer players with thermography to prevent this type of injury seems to be an optimal strategy in order to reduce its prevalence.
Case study of a soccer player: prevention of a potential bone fracture.
In this case study, we present in figure 1 a professional soccer player, who on November 19 presented an asymmetry in the right foot of +0.69 ºC above the normative values for that region and for his individual profile. At that time, there are no concomitant discomforts.
In the following evaluation (November 23), an increase in the asymmetry of that region can be seen, reaching 0.94 ºC of hyperthermic asymmetry. At that moment, the player’s sensation in that region is almost non-existent, but it is a really good time to monitor the work the player is going to do. It is also ideal to suggest some type of strategy that helps reduce asymmetry (for example, orthotic treatment, change of boots or training adaptation).
The third evaluation (November 26) is undoubtedly the most worrying of all. Since no management strategies were finally carried out, in addition to the increase in temperature to +1.25 ºC, the player reported discomfort in the region of 4/10 in the VAS. Finally, we proceeded to adapt the training and load management.
From the ThermoHuman team, we value this case as an example of prevention due to several factors:
- Even before the player noticed discomfort in the region, thermography had warned us of a significant hyperthermic change in the foot right.
- The adaptation of the training load suggested by the evaluation of the thermography avoided risk in that region, which is especially susceptible to this type of fracture.
- In addition, the fact that the adaptation of the load reduced the asymmetry indicates that this progressive process of temperature increase was not normal, and that we were facing a potential risk.
Conclusions
Thermography helps us in decision-making, reporting changes in the physiological state of body regions that, depending on the sport, 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.
References
Bennell KL, Malcolm SA, Wark JD & Brukner PD. Models for the pathogenesis of stress fractures in athletes. British journal of sports medicine. 1996, 30(3), 200-204.
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.
Devereaux MD, Parr GR, Lachmann SM, Page-Thomas P, Hazleman BL. The diagnosis of stress fractures in athletes. JAMA. 1984 Jul 27;252(4):531-3.
Escamilla-Galindo V, Fernández-Cuevas I, & del Estal-Martínez A. (2022). Description of the thermal pattern of 950 athletes using thermography to measure skin temperature. Conference paper: 27th Annual Congress of the European College of Sport Sciences (ECSS).
Finestone A, Milgrom C, Wolf O, Petrov K, Evans R, Moran D. Epidemiology of metatarsal stress fractures versus tibial and femoral stress fractures during elite training. Foot Ankle Int. 2011 Jan;32(1):16-20.
Formenti, D., Ludwig, N., Rossi, A., Trecroci, A., Alberti, G., Gargano, M., . . . Caumo, A. (2018). Is the maximum value in the region of interest a reliable indicator of skin temperature? Infrared Physics & Technology, 94, 299-304. doi: https://doi.org/10.1016/j.infrared.2018.06.017
Gómez-Carmona PM, Fernández-Cuevas I, Sillero-Quintana M, Arnáiz-Lastras J & Navandar A. Infrared Thermography Protocol on Reducing the Incidence of Soccer Injuries. Journal of Sport Rehabilitation. 2020
Goodman PH, Heaslet MW, Pagliano JW, Rubin BD. Stress Fracture Diagnosis by Computer-Assisted Thermography. Phys Sportsmed. 1985 Apr;13(4):114-32.
Matsuda S, Fukubayashi T, Hirose N. Characteristics of the Foot Static Alignment and the Plantar Pressure Associated with Fifth Metatarsal Stress Fracture History in Male Soccer Players: a Case-Control Study. Sports Med Open. 2017 Dec;3(1):27.
Okunuki T, Magoshi H, Maemichi T, Liu Z, Tanaka H, Matsumoto M, Hoshiba T, Kumai T. The prevalence and effect of the sites of pain in female soccer players with medial shin pain. J Sports Med Phys Fitness. 2022 Mar 25.
Sobhani S, Dekker R, Postema K, Dijkstra PU. Epidemiology of ankle and foot overuse injuries in sports: A systematic review. Scand J Med Sci Sports. 2013 Dec;23(6):669-86.
Vardasca R, Ring EFJ, Plassmann P, Jones CD & Gabriel J. Using clinical thermography as a diagnostic complementary procedure for hand arm vibration syndrome. Thermology International. 2012, 22(3), 94.
Warden SJ, Davis IS, Fredericson M. Management and prevention of bone stress injuries in long-distance runners. J Orthop Sports Phys Ther. 2014 Oct;44(10):749-65.
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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). 
