title: Single-leg balance and core motor control in children: when does the risk for ACL injury occurs?
abstract: BACKGROUND
  While numerous publications have demonstrated the correlation of poor single-leg balance and core motor control with an increased risk of anterior cruciate ligament (ACL) injuries in skeletally mature female athletes, few have analysed the preadolescent population regarding when indeed comparative deficits in balance and core control actually occur. The purpose of this study was to assess whether the neuromotor factors that place mature females at increased risk of ACL injury actually are present in preadolescents and if so when.
  
  
  METHODS
  This study used simplified modifications of classic drop-jump testing as well as single-leg balance tests performed on stable and unstable surfaces to assess balance and core motor control. 84 children (males and females) ranging in age from 6 to 13 years were divided into 4 equally sized groups based on their academic classes. Each group was compared with each other, and compared with a cohort of 205 collegiate athletes. The latter served as a comparative norm of mature athletes who had performed the same or similar testing.
  
  
  RESULTS
  Outcomes revealed that the preadolescent population performed poorly on the tests when compared with the collegiate population but the children matured with age until the eldest subgroups compared more favourably with the college-aged athletes. Girls appear to mature at a slightly earlier pace than boys. This study focusing on preadolescent children concluded that the neuromuscular changes that place females at greater risk of injury do not appear to occur prior to adolescence.
  
  
  CONCLUSIONS
  Based on the outcomes of this study, it is suggested that sex differences regarding balance and core control deficits that can increase risk of ACL injuries likely occur after grade school (age 12-13).
authors.affiliation: University of Illinois at Chicago , Chicago, Illinois , USA.
authors.forename: Allison B
authors.initials: AB
authors.lastname: Hutchinson
authors.affiliation: University of Illinois at Chicago , Chicago, Illinois , USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Yao
authors.affiliation: University of Illinois at Chicago , Chicago, Illinois , USA.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Hutchinson
keywords: ACL; Children; Core stability; Gender