Background: Overtraining (OVT) is a concern for many athletes. Immunological (increased interleukin-6 [IL-6]) and hormonal (increased cortisol [C], decreased free testosterone [fT]) biomarkers have been analyzed during training to detect OVT development.
Methods: This study determined if resting levels of salivary IL-6, T, and C change during a pre-season resistance training (RT) program in 20 Division I American football players (mean ± SD: age = 19.1 ± 1.1 years; height = 185.4 ± 6.7 cm; mass = 102.0 ± 22.2 kg; body fat = 14.7 ± 7.6%). 1RM squat, bench press and Olympic-style clean, IL-6, C and T were assessed at baseline (WK1), week 4 (WK4), week 6 (WK6) along with psychological status (PS) to determine affective state.
Results: 1RM (bench press: 121.6 ± 36.3 kg vs. 127.4 ± 35.9 kg, squat: 187.2 ± 30.2 kg, 190.9 ± 28.1 kg, clean: 116.8 ± 14.6 kg, vs. 119.2 ± 14.5 kg), IL-6 (1.42 ± 1.77 pg/mL vs. 5.60 ± 12.57 pg/mL) and C (2.57 ± 2.46 nmol/L vs. 5.33 ± 4.94) increased signihcantly from WK1 to WK6 (p < .05), fT decreased signihcantly (417.44 ± 83.63 pmol/Lvs. 341.10 ± 87.79 pmol/L) from WK1 to WK6 (p < .05). PS was minimally affected during the study. Signihcant biomarker changes were detected, but no OVT was induced (i.e. performance improved).
Conclusion: Therefore, directional changes in these biomarkers may not be sufficiently reflective of OVT in RT programs.
Keywords: anabolic-catabolic; biomarkers; hormones; stress.