title: Identifying relationships among lower extremity alignment characteristics.
abstract: BACKGROUND
  The relationship between lower extremity alignment and lower extremity injury risk remains poorly understood, perhaps because most authors have examined only individual or a select group of alignment variables. Examining the relationships among alignment variables may allow us to more accurately describe lower extremity posture and clarify the relationship between lower extremity alignment and injury risk in future studies.
  
  
  OBJECTIVE
  To measure lower extremity alignment variables and examine whether relationships could be identified among these variables.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Laboratory.
  
  
  METHODS
  Two hundred eighteen (102 males: age = 23.1 +/- 3.2 years, height = 177.3 +/- 8.4 cm, mass = 80.8 +/- 13.0 kg; 116 females: age = 21.8 +/- 2.7 years, height = 163.5 +/- 7.4 cm, mass = 63.4 +/- 12.4 kg) healthy, college-aged participants.
  
  
  METHODS
  We measured pelvic angle, femoral anteversion, quadriceps angle, tibiofemoral angle, genu recurvatum, and tibial torsion to the nearest degree and navicular drop to the nearest millimeter on the right and left lower extremities. Separate principal components factor analyses were performed for each sex and side (left, right).
  
  
  RESULTS
  A distinct lower extremity factor was identified, with relationships observed among increased pelvic angle, increased quadriceps angle, and increased tibiofemoral angle. A second distinct lower extremity factor was identified, with relationships observed among increased supine genu recurvatum, decreased tibial torsion, and increased navicular drop. Femoral anteversion loaded as an independent third factor. These distinct lower extremity alignment factors were consistent across side and sex.
  
  
  CONCLUSIONS
  Factor analysis identified 3 distinct lower extremity alignment factors that describe the potential interactions among lower extremity alignment variables. Future authors should examine how these collective alignment variables, both independently and in combination, influence dynamic knee function and risk for lower extremity injuries.
authors.affiliation: University of North Carolina at Greensboro, Greensboro, NC, USA. NguyenY@cofc.edu
authors.forename: Anh-Dung
authors.initials: AD
authors.lastname: Nguyen
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Shultz
mesh_terms: D000886:Anthropometry / Q000379:methods*; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000033:anatomy & histology* / Q000293:injuries; D008297:Male; D011187:Posture / Q000502:physiology; D025341:Principal Component Analysis; D018570:Risk Assessment; D012737:Sex Factors; D055815:Young Adult