title: Effects of Static Stretching and Playing Soccer on Knee Laxity.
abstract: OBJECTIVE
  This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  University biomechanics laboratory.
  
  
  METHODS
  Thirty-one athletes were randomly assigned into a stretching (26.9 ± 6.2 years, 1.77 ± 0.09 m, 67.9 ± 10.7 kg) and a control group (27.9 ± 7.4 years, 1.75 ± 0.08 m, 72.0 ± 14.9 kg). Thirty-one amateur soccer players in an additional soccer group (25.1 ± 5.6 years, 1.74 ± 0.10 m, 71.8 ± 14.8 kg). All participants had no history of knee injury requiring surgery and any previous knee ligament or cartilage injury.
  
  
  METHODS
  The stretching group performed 4 different static stretching exercises with a duration of 2 × 20 seconds interspersed with breaks of 10 seconds. The soccer group completed a 90-minute soccer-specific training program. The control group did not perform any physical activity for approximately 30 minutes.
  
  
  METHODS
  Anterior tibial translation was measured with the KT-1000 knee arthrometer at forces of 67 N, 89 N, and maximal manual force (Max) before and after the intervention.
  
  
  RESULTS
  There was a significant increase in ATT after static stretching and playing soccer at all applied forces. Maximal manual testing revealed a mean increase of ATT after static stretching of 2.1 ± 1.6 mm (P < 0.0005) and after playing soccer of 1.0 ± 1.5 mm (P = 0.001). The ATT increase after static stretching at 67 and 89 N is significantly higher than in controls. At maximum manual testing, significant differences were evident between all groups.
  
  
  CONCLUSIONS
  Static stretching and playing soccer increase ATT and may consequently influence mechanical factors of the anterior cruciate ligament. The ATT increase after static stretching was greater than after playing soccer.
  
  
  CONCLUSIONS
  The observed increase in ATT after static stretching and playing soccer may be associated with changes in kinesthetic perception and sensorimotor control, activation of muscles, joint stability, overall performance, and higher injury risk.
authors: *Research Center for Performance Diagnostics and Training Advice, University of Wuppertal, Wuppertal, Germany; †University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, The Netherlands; and ‡Department of Sport, Exercise and Health, University of Basel, Basel, Switzerland.
authors: Christian
authors: C
authors: Baumgart
authors: Alli
authors: A
authors: Gokeler
authors: Lars
authors: L
authors: Donath
authors: Matthias W
authors: MW
authors: Hoppe
authors: Jürgen
authors: J
authors: Freiwald
mesh_terms: D000328:Adult; D056352:Athletes; D006801:Humans; D007593:Joint Instability; D007719:Knee Joint / Q000502:physiology*; D052580:Muscle Stretching Exercises / Q000379:methods*; D012916:Soccer / Q000293:injuries / Q000502:physiology*; D055815:Young Adult