Competitive stress assessment using salivary biomarkers in rhythmic gymnasts

Stress and adaptation are inevitable components of the gymnastics training in competitive gymnasts. Salivary biomarkers, such as alpha-amylase activity (sAAA), concentration of protein (sP) and potassium (sK+) are useful non-invasive stress indicators. The aim of this study was to assess the stress levels before training and competitions in rhythmic gymnasts by using non-invasive biochemical salivary stress markers and anxiety questionnaires. The study included 10 national level rhythmic gymnasts (mean age: 14.7±1.57 years). Saliva was collected by salivates at three time points: nine days pre-competition at home (baseline), five days pre-competition before a training session, and just before the competition. The sAAA and the sP and sK+ were measured. Trait and state anxiety were evaluated by the State-Trait Anxiety Inventory. At baseline, the mean sAAA was 5.89±0.75 ln(U/mL) and increased significantly to 6.56±0.58 ln(U/mL) just before the training session (p<0.05) and increased further to 6.90±0.70 ln(U/mL) just before the competition (p<0.05 vs baseline). The mean sP increased progressively insignificantly 1.84±0.70 g/L vs 2.28±0.97 g/L vs 2.91±1.44 g/L, respectively. The mean sK+ 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). 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 to that before the competition (40.10±9.57 vs 30.80±10.26, p<0.05). In conclusion, the sAAA and sK+ were both in agreement with the anxiety scores, and they can be applied as useful and objective non-invasive markers of stress.