Muscle heating is the process that every athlete follows before any physical activity or sport which are the legs where greater force is exerted and in case a good heating routine is not practiced, the muscles can suffer tears, cramps or fractures due to sudden movements while the muscles are cold. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the United States, the most common injuries occur in the ankles because it is a central point where greater force is exerted by the induced weight of the athletes, in addition if excessive muscle care is important. That is why the evaluation of muscle heating in athletes to prevent muscle damage was raised in this research work, first two thermal images of the before and after heating will be obtained using the FLIR ONE Pro thermal camera following a protocol of distance, position and temperature range, then the images are processed in the MATLAB software to map them in the temperature range and then subtract them to obtain the zones where the temperature variations are found indicating where an adequate heating has been carried out. As a result, the areas where the subtraction of both images was positive were obtained, this new image of the subtraction is superimposed on the real image, showing the real image with the areas where it has proceeded with an optimal heating.