title: Influence of external ankle support on lower extremity joint mechanics during drop landings.
abstract: OBJECTIVE
  To investigate the effects of external ankle support (EAS) on lower extremity joint mechanics and vertical ground-reaction forces (VGRF) during drop landings.
  
  
  METHODS
  A 1 x 3 repeated-measures, crossover design.
  
  
  METHODS
  Biomechanics research laboratory.
  
  
  METHODS
  13 male recreationally active basketball players (age 22.3 +/- 2.2 y, height 177.5 +/- 7.5 cm, mass 72.2 +/- 11.4 kg) free from lower extremity pathology for the 12 mo before the study.
  
  
  METHODS
  Subjects performed a 1-legged drop landing from a standardized height under 3 different ankle-support conditions.
  
  
  METHODS
  Hip, knee, and ankle angular displacement along with specific temporal (TGRFz1, TGRFz2; s) and spatial (GRFz1, GRFz2; body-weight units [BW]) characteristics of the VGRF vector were measured during a drop landing.
  
  
  RESULTS
  The tape condition (1.08 +/- 0.09 BW) demonstrated less GRFz1 than the control (1.28 +/- 0.16 BW) and semirigid conditions (1.28 +/- 0.21 BW; P < .0001), and GRFz2 was unaffected. For TGRFz1, no-support displayed slower time (0.017 +/- 0.004 s) than the semirigid (0.014 +/- 0.001 s) and tape conditions (0.014 +/- 0.002 s; P < .05). For TGRFz2, no-support displayed slower time (0.054 +/- 0.006 s) than the semirigid (0.050 +/- 0.006 s) and tape conditions (0.045 +/- 0.004 s; P < .05). Semirigid bracing was slower than the tape condition, as well (P < .05). Ankle-joint displacement was less in the tape (34.6 degrees +/- 7.7 degrees) and semirigid (36.8 degrees +/- 9.3 degrees) conditions than in no-support (45.7 degrees +/- 7.3 degrees; P < .05). Knee-joint displacement was larger in the no-support (45.1 degrees +/- 9.0 degrees) than in the semirigid (42.6 degrees +/- 6.8 degrees; P < .05) condition. Tape support (43.8 degrees +/- 8.7 degrees) did not differ from the semirigid condition (P > .05). Hip angular displacement was not affected by EAS (F(2,24) = 1.47, P = .25).
  
  
  CONCLUSIONS
  EAS reduces ankle- and knee-joint displacement, which appear to influence the spatial and temporal characteristics of GRFz1 during drop landings.
authors.affiliation: Biodynamics Research Laboratory, Department of Kinesiology, and Center for Biomedical Engineering Systems, University of North Carolina, Charlotte, NC, USA.
authors.forename: Mitchell L
authors.initials: ML
authors.lastname: Cordova
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Kress
authors.forename: Jody B
authors.initials: JB
authors.lastname: Brucker
authors.forename: Alfred E
authors.initials: AE
authors.lastname: Finch
mesh_terms: D000704:Analysis of Variance; D016512:Ankle Injuries / Q000209:etiology / Q000517:prevention & control; D000843:Ankle Joint / Q000502:physiology*; D055052:Athletic Tape; D001490:Basketball / Q000293:injuries / Q000502:physiology*; D001696:Biomechanical Phenomena; D001915:Braces; D016001:Confidence Intervals; D018592:Cross-Over Studies; D003654:Deceleration; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology; D011187:Posture; D016059:Range of Motion, Articular; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult