title: Dynamic balance ability in young elite soccer players: implication of isometric strength.
abstract: BACKGROUND
  Soccer requires maintaining unilateral balance when executing movement with the contralateral leg. Despite the fact that balance requires standing with maintaining isometric posture with the support leg, currently there is a lack of studies regarding the implication of isometric strength on dynamic balance's performance among young soccer players. Therefore, the aim of this study was to examine the relationship between the Y-Balance Test and 12 lower limbs isometric strength tests.
  
  
  METHODS
  Twenty-six right footed soccer players (mean±SD, age=16.2±1.6 years, height=175±4.2 cm, body mass=68.8±6.1 kg) performed a dynamic balance test (star excursion balance-test with dominant- (DL) and nondominant-legs (NDL). Furthermore, maximal isometric contraction tests of 12 lower limb muscle groups were assessed in DL and NDL.
  
  
  RESULTS
  Correlations analysis reported a significant positive relationship between some of isometric strength tests (with DL and NDL) and the Y-Balance Test. Furthermore, stepwise multiple regression analysis showed that maximal isometric strength explained between 21.9% and 49.4% of the variance of the Y-Balance Test. Moreover, maximal isometric strength was dependent upon the reaching angle of the Y-Balance Test and the leg used to support body weight.
  
  
  CONCLUSIONS
  This study showed a significant implication of maximal isometric strength of the lower limb and the Y-Balance Test. Moreover, the present investigation suggests the implementation of specific lower limb strengthening exercises depending on players' deficit in each reaching direction and leg. This result suggests that further studies should experiment if increasing lower limbs isometric strength could improve dynamic balance ability among young soccer players.
authors.affiliation: Tunisian Research Laboratory &quot;Sport Performance Optimization&quot;, National Center of Medicine and Science in Sports, Tunis, Tunisia.
authors.forename: Moktar
authors.initials: M
authors.lastname: Chtara
authors.affiliation: Tunisian Research Laboratory &quot;Sport Performance Optimization&quot;, National Center of Medicine and Science in Sports, Tunis, Tunisia - mehdirwissi@gmail.com.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Rouissi
authors.affiliation: School of Public Health, Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy.
authors.forename: Nicola L
authors.initials: NL
authors.lastname: Bragazzi
authors.affiliation: Servette Football Club, Geneva, Switzerland.|Claude Bernard University Lyon, Centre de Recherche et d'Innovation sur le Sport (CRIS), Villeurbanne, France.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Owen
authors.affiliation: Sport Science Program, College of Arts and Sciences, University, Doha, Qatar.
authors.forename: Monoem
authors.initials: M
authors.lastname: Haddad
authors.affiliation: Athlete Health and Performance Research Center, ASPETAR, Qatar Orthopedic and Sports Medicine Hospital, Doha, Qatar.
authors.forename: Karim
authors.initials: K
authors.lastname: Chamari
mesh_terms: D000293:Adolescent; D000328:Adult; D006801:Humans; D007537:Isometric Contraction; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D009068:Movement; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000502:physiology; D012916:Soccer / Q000502:physiology*