title: Effects of a 10-week in-season eccentric-overload training program on muscle-injury prevention and performance in junior elite soccer players.
abstract: OBJECTIVE
  To analyze the effect of an eccentric-overload training program (ie, half-squat and leg-curl exercises using flywheel ergometers) with individualized load on muscle-injury incidence and severity and performance in junior elite soccer players.
  
  
  METHODS
  Thirty-six young players (U-17 to U-19) were recruited and assigned to an experimental (EXP) or control group (CON). The training program consisted of 1 or 2 sessions/wk (3-6 sets with 6 repetitions) during 10 wk. The outcome measured included muscle injury (incidence per 1000 h of exposure and injury severity) and performance tests (countermovement jump [CMJ], 10-m and 20-m sprint test).
  
  
  RESULTS
  Between-groups results showed a likely (ES: 0.94) lower number of days of absence per injury and a possible decrement of incidence per 1000 h of match play in EXP than in CON. Regarding muscle performance, a substantial better improvement (likely to very likely) was found in 20-m sprint time (ES: 0.37), 10-m flying-sprint time (ES: 0.77), and CMJ (ES: 0.79) for EXP than for CON. Within-group analysis showed an unclear effect in each variable in CON. Conversely, substantial improvements were obtained in CMJ (ES: 0.58), 20-m sprint time (ES: 0.32), 10-m flying-sprint time (ES: 0.95), and injury severity (ES: 0.59) in EXP. Furthermore, a possible decrement in total injury incidence was also reported in EXP.
  
  
  CONCLUSIONS
  The eccentric-based program led to a reduction in muscle-injury incidence and severity and showed improvements in common soccer tasks such as jumping ability and linear-sprinting speed.
authors.affiliation: Fitness Section, Sevilla Football Club, Seville, Spain.
authors.forename: Moisés
authors.initials: M
authors.lastname: de Hoyo
authors.forename: Marco
authors.initials: M
authors.lastname: Pozzo
authors.forename: Borja
authors.initials: B
authors.lastname: Sañudo
authors.forename: Luis
authors.initials: L
authors.lastname: Carrasco
authors.forename: Oliver
authors.initials: O
authors.lastname: Gonzalo-Skok
authors.forename: Sergio
authors.initials: S
authors.lastname: Domínguez-Cobo
authors.forename: Eduardo
authors.initials: E
authors.lastname: Morán-Camacho
mesh_terms: D000293:Adolescent; D054874:Athletic Performance / Q000502:physiology; D006801:Humans; D007869:Leg Injuries / Q000517:prevention & control*; D008297:Male; D018482:Muscle, Skeletal / Q000293:injuries*; D010806:Physical Education and Training / Q000379:methods*; D055070:Resistance Training; D012916:Soccer / Q000293:injuries*