title: Effects of seven weeks of static hamstring stretching on flexibility and sprint performance in young soccer players according to their playing position.
abstract: BACKGROUND
  The aim of this study was to investigate the effect of 7 weeks of static hamstring stretching on flexibility and sprint performance in young soccer players.
  
  
  METHODS
  One hundred and three healthy soccer players voluntarily participated in this study. Subjects were assigned to a control group (N.=22, 16.5±0.7 years, 174.0±5.4 cm and 68.0±6.8 kg) and an experimental group (N.=81, 18.9±1.8 years, 176.0±5.8 cm and 68.2±8.4 kg). All subjects performed a sit-and-reach and a 30-m Sprint Test to assess their flexibility performance and sprinting ability, respectively, before and after 7 weeks of static hamstring stretching program. The static stretching program consisted of 4 stretching exercises performed at the end of the training session during 6 days per week. Each stretch was held for 30-s and performed twice with a 15-s rest between.
  
  
  RESULTS
  Flexibility was significantly (P<0.05) improved for the experimental group. This improvement was analyzed in all playing positions studied. There were significant differences (P<0.05) between pre and post 30-m Sprint Test in both groups. All soccer positions significantly (P<0.05) improved their performance in the experimental group. However, in the control group only defenders improved significantly (P<0.05) the sprint time.
  
  
  CONCLUSIONS
  The use of static stretching at the end of the training sessions prevents the negative effect of the load on hamstring flexibility and it can influence improvement in flexibility.
authors.affiliation: Department of Physical Education and Sports, University of León, Institute of Biomedicine (IBIOMED), León, Spain - arodrf06@estudiantes.unileon.es.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Rodriguez Fernandez
authors.forename: Javier
authors.initials: J
authors.lastname: Sanchez
authors.forename: José A
authors.initials: JA
authors.lastname: Rodriguez Marroyo
authors.forename: José G
authors.initials: JG
authors.lastname: Villa
mesh_terms: D000293:Adolescent; D054874:Athletic Performance / Q000502:physiology*; D015444:Exercise; D005081:Exercise Therapy; D006293:Health Promotion; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D052580:Muscle Stretching Exercises / Q000379:methods*; D018583:Pliability; D012916:Soccer; D055815:Young Adult