title: Knee biomechanics during landings: comparison of pre- and postpubescent females.
abstract: OBJECTIVE
  The purpose of this investigation was to examine lower-extremity biomechanical differences between prepubescent and postpubescent female recreational athletes during three drop jump-landing sequences (static landing, vertical landing, and lateral landing) to determine whether maturation influenced injury risk.
  
  
  METHODS
  Sixteen recreationally active postpubescent women (18-25 yr of age) and 16 recreationally active girls (8-11 yr of age) participated in this study. High-speed three-dimensional videography and force plate data were recorded for each subject's performance of the landing tasks and an inverse dynamics procedure was used to estimate knee joint resultant moments and forces. Kinematic and kinetic dependent variables were analyzed in three separate mixed-design 2 x 3 (maturation level x landing sequence) repeated measures multivariate analysis of variance.
  
  
  RESULTS
  Statistical analyses indicated significant maturation level x landing sequence interactions for postpubescent participants who exhibited reduced knee flexion (4.5 degrees ) at initial contact, increased mediolateral knee joint forces [prepubescent: -0.63 +/- 0.21 N.(kg. radicalLH)(-1), postpubescent: 0.55 +/- 0.21 N.(kg. radicalLH)(-1)], and reduced knee extensor moments [prepubescent: -0.0124 +/- 0.001 N.m.(kg.BH. radicalLH)(-1), postpubescent: -0.0079 +/- 0.001 N.m.(kg.BH. radicalLH)(-1)] compared with their prepubescent counterparts.
  
  
  CONCLUSIONS
  These findings suggest that developmental changes influence knee mechanics during landings in female athletes and highlight the need to examine multiple landing patterns when investigating landing strategies.
authors.affiliation: Department of Biobehavioral Sciences, Teachers College, Columbia University, 525 West 120th Street, Box 199, New York, NY 10027, USA. hass@exhange.tc.columbia.edu
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Hass
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Schick
authors.forename: Mark D
authors.initials: MD
authors.lastname: Tillman
authors.forename: John W
authors.initials: JW
authors.lastname: Chow
authors.forename: Denis
authors.initials: D
authors.lastname: Brunt
authors.forename: James H
authors.initials: JH
authors.lastname: Cauraugh
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001265:Athletic Injuries / Q000209:etiology / Q000503:physiopathology; D001696:Biomechanical Phenomena; D002648:Child; D005260:Female; D006801:Humans; D007717:Knee / Q000502:physiology*; D035002:Lower Extremity / Q000502:physiology; D012307:Risk Factors; D013177:Sports / Q000502:physiology*