Background: Training programs of athletes for high level competitive sport may cause physical and emotional stress with deleterious effects on cognitive, behavioral, and physiological
aspects, thus impairing athlete’s performance. Therefore, monitoring the stress markers during training enables to have a better control of the training workload, in order to reach the maximum
performance in the competitive periods. Heart rate variability (HRV), creatine kinase (CK) and cortisol concentrations, and mood state are the most used stress biomarkers. The goal of this study was
to determine and to analyze the correlation among HRV, CK, salivary cortisol (SC) and mood state during the preseason training of professional female soccer athletes.
Methods: 27 female, 18-30 year-old, professional soccer players of the national first division team were evaluated. HRV indices were calculated based on the RR intervals in the
electrocardiogram, that was recorded with the athlete in the supine position, using Polar® RS800CX. CK activity was evaluated in a blood sample using the Reflotron Analyser®. Cortisol was analyzed by
Elisa in saliva samples collected immediately after awakening (CD) and at night (CN). The mood state was estimated using the Brunel Mood Scale (BRUMS). Data are presented as means ± standart
deviation. Spearman correlation among variables was also determined and the significance level was set at 5%.
Results: The BRUMS vigor index of 8.8±3.5 indicates a positive mood, featuring energy states, animation and activity, essential for an athlete proper performance of an athlete. CK
plasma concentration (105±75.8 U/L), CD (7.44±3.0 nmol/L) and CN (1.65±2.0 nmol/L) were within the normal range for female athletes in the age group of this study. HRV indices were as follows: RR
(1070±160.0 ms), RMSSD (80.0±40.4 ms) and pNN50% (47.1±18.9) in time domain; LF (1479.9±1121.5 ms²), HF (1869.3±1628.5 ms²), and LF / HF (0.80±0.61) in the frequency domain; SD1 (54.3±23.2 ms) and SD2
(95.5±43.8 ms) for the Poincare plot. No significant correlations were found between CK and the other physiological and psychological markers. There were moderates correlations between CN and RR (r =
0.66); CN and anger (r = -0.51); SD2 and mood state mental confusion (r = 0.42) and between SD2; mood state vigor (r = 0.43).
Conclusions: CK concentration, SC and mood state indicate that the athletes are in good physical and psychological conditions to start the training season. The correlation between SC,
HRV and mood states, namely anger, vigor and mental confusion, can be used to continuously evaluate the periodization program, reducing stress, and thus contributing for the athlete’s general health