Precompetitive Stress In Rhythmic Gymnasts Assessed By Using Salivary Alpha-amylase, Protein And Potassium

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Stress and adaptation are primary components of training and competitions in rhythmic gymnastics. This sport requires gymnasts to demonstrate maximum physical effort under great psychological pressure. Non-invasive biomarkers, such as salivary alpha-amylase (sAA), function as useful indicators of stress in acute and chronic stress studies. PURPOSE: To assess the pre-competitive stress levels in rhythmic gymnasts by using non-invasive biochemical methods and anxiety questionnaires. METHODS: The study included 10 rhythmic gymnast competitors (age: 14.7 ± 1.57 years), at the Bulgarian Rhythmic Gymnastics Championships. Saliva was collected by using cotton swab salivates without salivary stimulation at three different times: at home nine days pre-competition (baseline), before a training session five days pre-competition, and just before the competition. The sAA activity and the concentration of salivary protein (sP) and salivary potassium (K+) were measured. Trait and state anxiety were evaluated by using the Spielberger State-Trait Anxiety Inventory. Comparisons were made using one-way ANOVA with repeated measures. RESULTS: The mean state anxiety score was significantly higher before the training session in contrast to the baseline, 36.90 ± 11.03 vs 30.80 ± 10.26, p < 0.05 and before the competition, 40.10 ± 9.57 vs 30.80 ± 10.26, p < 0.05). The mean sAA activity was 5.89 ± 0.75 ln(U/mL) at baseline, and increased significantly to 6.56 ± 0.58 ln(U/mL) just before the training session (p < 0.05), and it was 6.90 ± 0.70 ln(U/mL) before the competition (p < 0.05 vs baseline). The mean sP concentration increased progressively but the differences were not significant 1.84 ± 0.70 [g/L] vs 2.28 ± 0.97 [g/L] vs 2.91 ± 1.44 [g/L], respectively. The mean salivary K+ concentration was significantly higher before the competition vs the baseline value (35.73 ± 8.3 mmol/L vs 23.94 ± 4.83 mmol/L, p < 0.01). CONCLUSIONS: The sAA activity and salivary K+ concentration were both in agreement with the anxiety scores, and they can be applied as useful non-invasive biomarkers of stress. A combination of psychological, biochemical and physiological indicators should be used to establish a comprehensive assessment of stress in competitive sport.