Bezuglov, E, Shvets, E, Lyubushkina, A, Lazarev, A, Valova, Y, Zholinsky, A, and Waśkiewicz, Z. Relative age effect in Russian elite hockey. J Strength Cond Res 34(9): 2522–2527, 2020—A considerable amount of literature has been published on relative age effect (RAE) in many sports; however, only a few studies have investigated this phenomenon in European elite ice hockey. The objective of this research was to study RAE prevalence in Russian elite ice hockey, which for years has been holding leading positions in global ice hockey. To estimate RAE prevalence, birthdates of recruits of leading ice hockey academies, players of the leading junior and adult teams, and most successful Russian-born National Hockey League (worlds' strongest ice hockey league) players were identified (n = 2,285). A high prevalence of RAE was identified. The number of players born in the first half of the year was higher than those born later in the year—65.5 and 34.5%, respectively. The RAE prevalence was high among all age groups of recruits of the leading Russian hockey academies and junior teams. In contrast to junior hockey, more players born in the fourth quarter of the year were identified in elite adult teams. The high prevalence of RAE in Russian hockey might be explained by the fact of a high level of competition among young players during recruitment to hockey academies. Moreover, the coaches aim to achieve immediate progress, thus selecting more mature players who are better physically developed. However, “later-born” are widely present in elite adult ice hockey leagues.

Relevance. Influence of psychological stress on individuals can be assessed by heart rate variability (HRV) analysis. The syndrome of mental "burning out" often reflects psychological stress in physicians. Aim. The study addresses relation between HRV and the severity of professional stress among medical students with initial symptoms of arterial hypertension under dynamic physical exertion. Material and methods: 98 people took part in our research: 50 students of first years, 20 of which tended to have high blood pressure (BP), and 48 doctors-interns. Professional stress was diagnosed by V.V. Boyko's technique. BP by Korotkov's method and HRV analysis of the electrocardiogram (using Cardiotechnique-04) were taken while veloergometry at 100 Vt was performed. Results. 90 % of students are under I phase of stress strain that is accompanied by the increase of diastolic BP (р < 0,05). Out of studied hemodynamic parameters (systolic and diastolic BP, heart rate) only systolic BP was found to decrease till 124,6 ± 4,58 mmHg (p < 0,05) in 32,5 % of subjects under II phase of stress having got 5-minute rest after physical exertion. Sympathetic nervous system activity assessed by the decrease of HRV parameters and LF/HF-ratio increase was prevalent in the same group.