Description of the thermal pattern of 950 athletes using thermography to measure skin temperature

Abstract

INTRODUCTION: Infrared thermography is a fast technology that allows non-invasive measurement of skin temperature. This tool has been applied in the scientific literature for the control of training workloads and the prevention of injuries, since it allows detecting the body regions that present the greatest risk of injury. This has been shown, especially when thermal asymmetries are used in the analysis (Car- mona P. et al. 2020; Corte A. et al. 2019). The objective of this study was to identify and describe the distribution of thermal asymmetries in athletes in order to describe normal values and be able to establish individualized profiles.
METHODS: 950 athletes measured by the same observer were analyzed including only thermography images in a basal state, according to the indications of the Glamorgan protocol (Ammer K. et. al. 2008). The images were taken with a FLIR T530 camera (Flir Teledyne systems, Sweden) and analyzed using the automatic ThermoHuman software (Pema Termo Group, Spain), scientifically validated for this purpose (Requena-Bueno L. et al. 2020). Thermal analysis was performed anonymously, extracting data from 80 regions of interest (ROI) using an artificial vision algorithm and displaying the average, minimum, and maximum temperature results for each ROI. The system automatically compared the ROIs of both sides to obtain the mean asymmetry metric, that is, the difference between the mean temperature of one ROI and its contralateral.
RESULTS: The asymmetry values showed a mean difference of (0.004oC ± 0.66oC) in all ROIs. When the ROIs were analyzed individually, the most stable with the least mean asymmetry were: the ROI of the chest (0.007oC ± 0.16oC), the trapezius in its frontal view (0.008oC ± 0.24oC), the lower back region (0.007oC ± 0.26oC) and the vastus medialis (0.003oC ± 0.27oC). While the greatest differences were found in the foot in the posterior view (0.37oC ± 3.73oC), the wrist in both anterior and posterior views (0.16oC ± 0.72oC; 0.09oC ± 0.65oC), the shoulder in the posterior view (0.09oC ± 1.47oC) and the vastus lateralis (0.09oC ± 0.40oC). In addition, the regions with the greatest varia- bility were: the neck (0.03oC ± 2.10oC; 0.01oC ± 2.04oC) and the foot (0.005oC ± 2.26oC; 0.37oC ± 3.73oC), both in its anterior and posterior views.
CONCLUSION: A normality profile of athletes using thermography to analyze the skin temperature of the ROIs was established. This allows the comparison of a new athlete with the database of the 950 athletes. In addition, as has been verified with the descriptive analysis of this sample, the ROIs show a degree of similarity very close to symmetry when a large number of evaluations are included, even without know- ing the factors of influence. This facilitates the generation of individualized thermal profiles that can improve the understanding and use- fulness of thermographic analysis.