Is thermography capable of identifying physiological stress induced by a protocol of repeated sprints in university athletes?

This study aimed to analyse the effects of a repeated sprint protocol on skin temperature (Tsk) and biochemical, neuromuscular, and psychophysiological indicators in university athletes. Thirty men, soccer and futsal players, and sedentary individuals, completed 15 maximal 30-m sprints with 1-min recovery intervals. Thermograms, biochemical samples, perceived recovery (TQR), and neuromuscular performance were collected 48 h before, immediately before, and 24 and 48 h after the intervention. Mean Tsk values for each region of interest (ROI) were used in the statistical analysis. A two-factor repeated-measures ANOVA with Bonferroni post hoc adjustment was used to compare responses between groups over time. No significant difference was observed between groups for any variable. Over time, the protocol induced muscle damage and triggered an inflammatory response, with increases observed in creatine kinase (Δ = 181.6 u/L; p = 0.01), uric acid (Δ = 0.9 mg/dL; p < 0.001), and C-reactive protein (Δ = 1.1 mg/L; p = 0.005). Also, performance in countermovement jump (Δ = 3,4 cm; p < 0.001) and TQR scores decreased (Δ = 5.5 AU; p < 0.001) post-intervention. However, Tsk showed no significant changes in any ROI. In conclusion, Tsk was not a sensitive indicator for detecting muscle damage induced by repeated sprints. The protocol caused muscle damage in both trained and sedentary young men, and results suggest that physical activity level and training specificity did not influence most responses, except for TQR.