Autonomic support of central hemodynamics and physical working capacity in female swimmers and runners in a one-year training cycle

Abstract

The aim of the work is to assess dynamic changes in heart rate variability (HRV), central hemodynamics and physical performance in female swimmers at a distance of 50–200 meters and female runners at a distance of 400 meters in the preparatory and competitive periods of the training process. Materials and methods. At the beginning of the preparatory period and at the end of the competitive period, 11 female swimmers were examined, including 1 athlete – Master of Sports of Ukraine (MSU), 7 athletes – Candidate Masters of Sports (CMS), 1 – first-class athlete, 2 – second-class athletes, and 22 female runners, including 1 athlete – Master of Sports of Ukraine of International Class (MSUIC), 3 athletes – Candidate Masters of Sports, 7 first-class athletes, 8 – second-class athletes and 3 – third-class athletes. Time- and frequency domain methods of HRV analysis were used to assess the mechanisms of heart neurohumoral regulation. Central hemodynamic parameters were examined by an automated tetrapolar rheography according to W. Kubiček et al. (1970) modified by Yu. T. Pushkar et al. (1970). Physical working capacity (PWC) was measured using a submaximal PWC170 test. The functional state index (FSI) was calculated according to the formula that we had proposed and patented. Results. Analysis of HRV indices in female swimmers revealed the prevalence of parasympathetic influences in the competitive period. There was a central hemodynamics-related significant decrease in cardiac index (CI) in the competitive period, although its value corresponded to the eukinetic circulatory type (CT). The ratio of CTs was 18.2 %: 81.8 %: 0.0 %, hypokinetic, eukinetic and hyperkinetic CT, respectively, indicating a tendency towards eukinetic CT prevalence over hypokinetic one (P = 0.075) and the absence of athletes with physiologically unfavorable hyperkinetic CT. The PWC170/kg value increased by an average of 12.44 %, from 12.860 ± 0.732 kgm·min-1·kg-1 to 14.460 ± 0.823 kgm·min-1·kg-1 (P = 0.002), and FSI – of 22.21 % (P = 0.0005) and corresponding to “below average” score. In the competitive period, 2 CMS female athletes qualified for MSU, 1 first-class athlete qualified for CMS, and 2 second-class athletes achieved the first-class sport qualification. Conclusions. Female swimmers demonstrated the significant prevalence of parasympathetic effects of the ANS, the tendency towards the eukinetic CT predominance and the absence of hyperkinetic CT, significantly increased PWC170/kg value by 12.44 % and FSI – by 22.21 % in the competitive period as compared with the preparatory period. The correlation analysis to assess both periods revealed the important relationship between heart rate (HR) and autonomic rhythm index (ARI), HR and indicator of the adequacy of regulation processes (IARP), indicating that training-induced bradycardia shifted the autonomic balance towards the predominance of the parasympathetic arm of the ANS. Decreased ARI caused the decrease in СI, resulting in the transformation of hyperkinetic CT into eukinetic one and the absence of physiologically unfavorable hyperkinetic CT in the athletes. The increased functional state of female swimmers in the competitive period helped to achieve improvements in their athletic performance.