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<b>Salivary alpha-amylase, heart rate and heart-rate variability in response to an experimental model of competitive stress in volleyball players</b>
Abstract
Contemporary sport events including volleyball lead to greater mental stress and more pronounced stress reactions among competitors which affect performance. The evaluation of pre-competition and competition stress levels is important and increasingly non-invasive assessment techniques in saliva are used. The aim of this study was to investigate the possibility of evaluation of volleyball players’ stress resistance, using salivary alpha-amylase (sAA) activity, heart rate (HR) and heart rate variability (HRV) during an experimental competition. Ten volleyball players aged 23.0 ± 1.94 years, stature 194.3 ± 2.5 cm were recruited. A competitive stress game model based on essential volleyball techniques was designed. HR and HRV indicators – standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive differences (rMSSD) were recorded. sAA and protein concentration were measured. HRavg and HRmax increased (p<0.001) during warm-up by 33% and by12.9% and during the experimental game by 21.2% and by 24% compared to baseline values (HRavg 99.8 ± 12.97bpm; HRmax 123 ± 14.71 bpm, respectively). sAA activity was lower (p<0.001) by 13.8% after warm-up and lower by 5% after the experimental game compared to baseline values. A significant decrease from the baseline (SDNN 87.52 ± 21.14 ms; rMSSD 42.20 ± 19.83 ms) by 35% and 50%, respectively, was found during the warm-up period. During the experimental game the values were reduced by 19.7% and by 28.9%. In conclusion, sAA and protein concentration are reliable tools for assessing stress in sports practice, as they complement HR and HRV and the use of combined approach could be recommended.
Keywords: Heart rate, heart rate variability, salivary alpha-amylase, stress, volleyball.