title: Retention of movement pattern changes after a lower extremity injury prevention program is affected by program duration.
abstract: BACKGROUND
  Changes in movement patterns have been repeatedly observed immediately after completing a lower extremity injury prevention program. However, it is not known if movement pattern changes are maintained after discontinuing the training program.
  
  
  OBJECTIVE
  The ability to maintain movement pattern changes after training has ceased may be influenced by the program's duration. The authors hypothesized that among individuals who completed either a 3-month or 9-month training program and who demonstrated immediate movement pattern changes, only those who completed the 9-month training program would maintain movement pattern changes after a 3-month period of no longer performing the exercises.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  A total of 140 youth soccer athletes from 15 separate teams volunteered to participate. Athletes' movement patterns were assessed using the Landing Error Scoring System (LESS) at pretest, posttest, and 3 months after ceasing the program (retention test). Eighty-four of the original 140 participants demonstrated improvements in their LESS scores between pretest and posttest (change in LESS score >0) and were included in the final analyses for this study (n = 84; 20 boys and 64 girls; mean age, 14 ± 2 years; age range, 11-17 years). Teams performed 3-month (short-duration group) and 9-month (extended-duration group) injury prevention programs. The exercises performed were identical for both groups. Teams performed the programs as part of their normal warm-up routine.
  
  
  RESULTS
  Although both groups improved their total LESS scores from pretest to posttest, only the extended-duration training group retained their improvements 3 months after ceasing the injury prevention program (F(2,137) = 3.38; P = .04).
  
  
  CONCLUSIONS
  Results suggest that training duration may be an important factor to consider when designing injury prevention programs that facilitate long-term changes in movement control.
authors: Department of Exercise and Sports Science, Sports Medicine Research Laboratory, University of North Carolina, Chapel Hill, 27599, USA. dpadua@email.unc.edu
authors: Darin A
authors: DA
authors: Padua
authors: Lindsay J
authors: LJ
authors: DiStefano
authors: Stephen W
authors: SW
authors: Marshall
authors: Anthony I
authors: AI
authors: Beutler
authors: Sarah J
authors: SJ
authors: de la Motte
authors: Michael J
authors: MJ
authors: DiStefano
mesh_terms: D000293:Adolescent; D000070598:Anterior Cruciate Ligament Injuries; D002648:Child; D004311:Double-Blind Method; D015444:Exercise; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D009048:Motor Skills; D009068:Movement; D010806:Physical Education and Training / Q000379:methods*; D012916:Soccer / Q000293:injuries*; D013997:Time Factors