Changes in the hormonal and inflammatory profile of young sprint- and endurance-trained athletes following a sports camp: a nonrandomized pretest-posttest study.

Background: The study aimed to compare catecholamine, cortisol, and immune response in sprint- and endurance-trained athletes under the same training, aiming to observe if their sport specialization affects these markers during a 9-day training camp.

Methods: The study involved twenty-four young male (age 15.7 ± 1.6 years) and female (age 15.1 ± 1,3 years) athletes specializing in sprint and endurance athletics discipline. Blood samples for all measured parameters were taken at rested baseline, on the 4th day, and on the 9th day of training.

Results: In both investigated groups a nonsignificant decrease in catecholamine levels was observed after 4 days of training, which remained stable throughout the camp. The cortisol level increased significantly in both athlete groups (sprint: T-0 vs. T-1 p = 0.0491; T-0 vs. T-3 p = 0.0001; endurance: T-0 vs. T-1 p = 0.0159; T-0 vs. T-3 p = 0.0005). The level of hs-CRP (sprint: T-0 vs. T-1 p = 0.0005; T-0 vs. T-3 p = 0.0001; endurance: T-0 vs. T-3 p = 0.0005), and myoglobin (sprint: T-0 vs. T-1 p = 0.0014; T-0 vs. T-3 p = 0.0001; endurance: T-0 vs. T-3 p = 0.0005) have increased and of hs-CRP and myoglobin level was significantly higher in sprint compared to endurance athletes (p < 0.05). The leukocyte level significantly decreased until the end of camp in both groups (sprint: T-0 vs. T-1 p = 0.0178; T-0 vs. T-3 p = 0.0175; endurance: T-0 vs. T-1 p = 0.0362; T-0 vs. T-3 p = 0.0362).

Conclusions: The applied training loads had a strong physiological impact leading to changes in stress hormones and immune responses depending on athletes` sport specialization. Training loads caused stronger responses in sprint athletes. However, both groups showed signs of severe fatigue development.

Trial registry: ClinicalTrials.gov ID: NCT06150105, retrospectively registered on 29.11.2023.