Salivary alpha-amylase, heart rate and heart-rate variability in response to an experimental model of competitive stress in volleyball players

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.