title: Bilateral differences in muscle architecture and increased rate of injury in national basketball association players.
abstract: BACKGROUND
  Professional basketball players have demanding schedules that, in combination with certain underlying physical characteristics and side-to-side strength and power imbalances, may make them vulnerable to lower extremity injuries.
  
  
  OBJECTIVE
  To examine the relationship among skeletal muscle architecture, lower body power, and games missed because of lower extremity injury (%MISS) in professional basketball players.
  
  
  METHODS
  Cross-sectional study. Setting : Human Performance Laboratory.
  
  
  METHODS
  Nine players under contract for Orlando Magic were assessed. We compared athletes who were injured (n = 4, height = 203.2 ± 5.5 cm, mass = 105 ± 7.5 kg, age = 25.0 ± 2.8 years) and those who remained healthy (n = 5, height = 200.2 ± 12.2 cm, mass = 100.1 ± 16.6 kg, age = 22.4 ± 1.9 years) during the season.
  
  
  METHODS
  Bilateral ultrasonographic measurements of muscle thickness, pennation angle, echo intensity, and cross-sectional area of the rectus femoris and vastus lateralis were collected before regular-season play. Subsequently, muscle thickness and pennation angle were used to compute fascicle length. Along with unilateral jumping power, inferences were made upon the magnitude of the relationship between the percentage bilateral difference in these measures and %MISS, as well as between injured and healthy athletes.
  
  
  RESULTS
  The data indicated likely relationships between %MISS and age (r = 0.772), and between %MISS and bilateral differences in rectus femoris cross-sectional area (7.8% ± 6.4%; r = 0.657) and vastus lateralis cross-sectional area (6.2% ± 4.8%; r = 0.521), as well as a possible relationship with vastus lateralis muscle thickness (7.9% ± 8.9%; r = 0.444). Echo-intensity differences in the vastus lateralis were greater in injured (8.0% ± 2.4%) versus healthy athletes (3.2% ± 2.0%). Although a 2-fold difference in mean jumping power was observed between injured (26.3 ± 14.9 W) and healthy athletes (13.6 ± 8.7 W), these differences were not statistically significant (P = .20).
  
  
  CONCLUSIONS
  In the present sample, lower extremity side-to-side differences may be related to an increased risk for lower extremity injury. Future researchers using larger sample sizes need to identify normal versus at-risk ranges for bilateral differences in muscle structure and power of the lower extremities of professional basketball players and athletes in other sports.
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise, University of Central Florida, Orlando;
authors.forename: Gerald T
authors.initials: GT
authors.lastname: Mangine
authors.forename: Jay R
authors.initials: JR
authors.lastname: Hoffman
authors.forename: Adam M
authors.initials: AM
authors.lastname: Gonzalez
authors.forename: Adam R
authors.initials: AR
authors.lastname: Jajtner
authors.forename: Tyler
authors.initials: T
authors.lastname: Scanlon
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Rogowski
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Wells
authors.forename: Maren S
authors.initials: MS
authors.lastname: Fragala
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Stout
mesh_terms: D000328:Adult; D056352:Athletes; D001265:Athletic Injuries / Q000209:etiology / Q000517:prevention & control; D001490:Basketball / Q000502:physiology*; D003430:Cross-Sectional Studies; D006801:Humans; D035002:Lower Extremity / Q000293:injuries*; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000502:physiology / Q000503:physiopathology; D004856:Postural Balance / Q000502:physiology; D013178:Sports Medicine / Q000379:methods; D014463:Ultrasonography
keywords: bilateral deficits; elite athletes; jump power; muscle imbalances; sport science