Background: Infrared thermography (IRT) is a non-invasive, non-contact tool for skin surface temperature (SST) measurement. IRT can be routinely used to quantify physiological changes
and their functions in humans in a resting state and during movement (Hildebrandt, Zeilberger, Ring, & Raschner, 2012). In medical research IRT is a valuable diagnosis tool. In sports medicine and
sport science, however, IRT has rarely been applied, which explains the need for scientific research in this area. Since the warm-up phase before athletic activity is said to lead to an increase of
body temperature and metabolic rate, the following is to examine the extent to which IRT can be used to diagnose the SST changes in the chest region after a 10-minute warm-up, and to estimate the
effects of ergometer training on general vs. local muscular warming.
Methods: 20 male sports students (23.0 ± 1.6 years; 75.8 ± 9.0 kg; 181.0 ± 6.8 cm) participated in this study. After a standardized preparation phase, the SST of the lower and upper
extremities and of the trunk was determined in a resting state. This was followed by a 10-minute warm-up phase on a standard bike ergometer set to 1.5 W/kg body weight and a cadence of 60-80 rpm.
After the warm-up, the SST was determined again for the 1st to the 10th minute of the post-strain phase. Room temperature and humidity were controlled and kept constant for the individual persons.
Results: The 10-minute warm-up resulted in significant change in the SST over the time of measurement (P<0.05). Furthermore, a significant difference of the SST among the different
areas of the body was found (P<0.05). The interaction between the time and the area of measurement was also significant (P<0.05). The drop in SST from resting state to the first measurement after the
10-minute warm-up phase was 1.16°C and 3.7% in the trunk musculature. The temperature of the arm musculature dropped by 0.59°C (1.9%), while the temperature of the leg musculature decreased by 1.12°C
(3.6%). Ten minutes after the warm-up, the SST of legs and arms was back at the initial state before the strain, but the trunk SST was still 0.74°C (2.3%) lower.
Conclusions: After a general 10-minute warm-up on the bike ergometer, a specific drop in the SST of the directly strained leg musculature and the indirectly strained trunk and arm
musculature occurs. The results serve as a proof for the fact that IRT is able to quantitatively and qualitatively determine the primarily used muscle group by analyzing the SST changes occurring
during athletic activities. IRT thus represents a procedure to show muscle groups used in sports by means of visual imaging capabilities that can be applied in sports didactics, as well.
Hildebrandt, C., Zeilberger, K., Ring, E. F. J., & Raschner, C. (2012). The application of medical infrared thermography in sports medicine. In K. R. Zaslav (Ed.), An international perspective on
topics in sports medicine and sports injury (pp. 257-274). Rijeka: InTech.