title: Analyses of heart rate variability in young soccer players: the effects of sport activity.
abstract: BACKGROUND
  The use of heart rate variability (HRV) in the management of sport training is a practice which tends to spread, especially in order to prevent the occurrence of states of fatigue.
  
  
  OBJECTIVE
  To estimate the HRV parameters obtained using a heart rate recording, according to different loads of sporting activities, and to make the possible link with the appearance of fatigue.
  
  
  METHODS
  Eight young football players, aged 14.6 years+/-2 months, playing at league level in Rhône-Alpes, training for 10 to 20 h per week, were followed over a period of 5 months, allowing to obtain 54 recordings of HRV in three different conditions: (i) after rest (ii) after a day with training and (iii) after a day with a competitive match.
  
  
  RESULTS
  Under the effect of a competitive match, the HRV temporal indicators (heart rate, RR interval, and pNN50) were significantly altered compared to the rest day. The analysis of the sympathovagal balance rose significantly as a result of the competitive constraint (0.72+/-0.17 vs. 0.90+/-0.20; p<0.05).
  
  
  CONCLUSIONS
  The main results obtained show that the HRV is an objective and non-invasive monitoring of management of the training of young sportsmen. HRV analysis allowed to highlight any neurovegetative adjustments according to the physical loads. Thus, under the effect of an increase of physical and psychological constraints that a football match represents, the LF/HF ratio rises significantly; reflecting increased sympathetic stimulation, which beyond certain limits could be relevant to prevent the emergence of a state of fatigue.
authors.affiliation: CHU Grenoble: Pôle Physiologie-Rééducation, Clinique Physiologie, Sommeil, Exercice: Unité Fonctionnelle-Recherche Exercice Santé, France. vbricout@chu-grenoble.fr
authors.forename: Véronique-Aurélie
authors.initials: VA
authors.lastname: Bricout
authors.forename: Simon
authors.initials: S
authors.lastname: Dechenaud
authors.forename: Anne
authors.initials: A
authors.lastname: Favre-Juvin
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D012916:Soccer / Q000502:physiology*