title: The effects of exercise for the prevention of overuse anterior knee pain: a randomized controlled trial.
abstract: BACKGROUND
  Anterior knee pain (AKP) is the most common activity-related injury of the knee. The authors investigated the effect of an exercise intervention on the incidence of AKP in UK army recruits undergoing a 14-week physically arduous training program.
  
  
  OBJECTIVE
  Modifying military training to include targeted preventative exercises may reduce the incidence of AKP in a young recruit population.
  
  
  METHODS
  Randomized controlled trial; Level of evidence, 1.
  
  
  METHODS
  A single-blind cluster randomized controlled trial was performed in 39 male and 11 female training groups (median age: 19.7 years; interquartile range, 17-25) undergoing phase 1 of army recruit training. Each group was randomly assigned to either an intervention (n = 759) or control (n = 743) protocol. The intervention consisted of 4 strengthening and 4 stretching exercises completed during supervised physical training lessons (7 per week). The control group followed the existing training syllabus warm-up exercises. The primary outcome was a diagnosis of AKP during the 14-week training program.
  
  
  RESULTS
  Forty-six participants (3.1%; 95% confidence interval [CI], 2.3-4.1) were diagnosed with AKP. There were 36 (4.8%; 95%CI, 3.5-6.7) new cases of AKP in the control group and 10 (1.3%; 0.7-2.4) in the intervention group. There was a 75% reduction in AKP risk in the intervention group (unadjusted hazard ratio = 0.25; 95% CI, 0.13-0.52; P < .001). Three participants (0.4%) from the intervention group were discharged from the military for medical reasons compared to 25 (3.4%) in the control group.
  
  
  CONCLUSIONS
  A simple set of lower limb stretching and strengthening exercises resulted in a substantial and safe reduction in the incidence of AKP in a young military population undertaking a physical conditioning program. Such exercises could also be beneficial for preventing this common injury among nonmilitary participants in recreational physical activity.
authors.affiliation: Centre for Human Performance, Rehabilitation and Sports Medicine, Defence Medical Rehabilitation Centre, Headley Court, Epsom, Surrey, KT18 6JW, England, UK. russ.coppack916@mod.uk
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Coppack
authors.forename: John
authors.initials: J
authors.lastname: Etherington
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Wills
mesh_terms: D000293:Adolescent; D000328:Adult; D018771:Arthralgia / Q000517:prevention & control*; D012090:Cumulative Trauma Disorders / Q000517:prevention & control*; D015444:Exercise; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000517:prevention & control*; D008297:Male; D008889:Military Personnel; D055815:Young Adult