title: Competition-Level Differences on the Lower Quarter Y-Balance Test in Baseball Players.
abstract: BACKGROUND
  Decreased performance in dynamic balance has previously been associated with a history of ulnar collateral ligament injury in baseball players. Previous research on dynamic balance in soccer players has shown that test performance depends on competition level. However, dynamic balance has yet to be examined in baseball players.
  
  
  OBJECTIVE
  To understand normative values and determine differences in dynamic balance, as measured by the Lower Quarter Y-Balance Test, across competition levels in baseball players.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Preseason physical examinations.
  
  
  METHODS
  Dynamic balance was measured in 88 high school (HS), 78 collegiate (COL), and 90 professional (PRO) baseball players.
  
  
  METHODS
  All participants completed the Lower Quarter Y-Balance Test using the standard protocol. In unilateral stance, they reached with 1 foot in the anterior, posteromedial, and posterolateral directions. We calculated 1-way analyses of variance to compare performance, composite score, and reach asymmetry for each direction as well as the sum of the asymmetry values (P < .05). Composite score was calculated by averaging the maximum normalized reach scores. Reach asymmetry was determined by calculating bilateral differences in reach ability.
  
  
  RESULTS
  In comparison with the HS and COL groups, the PRO players exhibited greater posteromedial (P < .01; effect size index [ESI]HS= 1.06, ESICOL= 0.95) and posterolateral reach (P < .01; ESIHS= 0.82, ESICOL= 0.84) as well as a greater composite score (P < .01; ESIHS= 0.60, ESICOL= 0.87). In contrast, HS baseball players exhibited increased anterior reach (P < .01; ESICOL= 0.60, ESIPRO= 0.39) compared with the COL and PRO cohorts. No significant differences in reach asymmetry were observed among groups.
  
  
  CONCLUSIONS
  Lower extremity dynamic balance performance differed based on the baseball players' competition level. These baseline data may be helpful in identifying low-performing athletes who might benefit from neuromuscular interventions.
authors.affiliation: Division of Physical Therapy, Duke University, Durham, NC.|Michael W. Krzyzewski Human Performance Laboratory, Duke University, Durham, NC.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Butler
authors.forename: Garrett
authors.initials: G
authors.lastname: Bullock
authors.affiliation: St Vincent's Sports Performance, Indianapolis, IN.
authors.forename: Todd
authors.initials: T
authors.lastname: Arnold
authors.forename: Phillip
authors.initials: P
authors.lastname: Plisky
authors.forename: Robin
authors.initials: R
authors.lastname: Queen
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001484:Baseball / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D012782:Shoulder; D013334:Students; D055815:Young Adult
keywords: collegiate athletes; dynamic balance; high school athletes; professional athletes