title: Leg stiffness, valgus knee motion, and Q-angle are associated with hypertrophic soft patella tendon and idiopathic knee pain in adolescent basketball players.
abstract: BACKGROUND
  Knee pain without knee degenerative symptoms is a common phenomenon among young basketball players. The aim of this study was to identify factors predisposing young basketball players to suffer from knee pain.
  
  
  METHODS
  The study involved 20 male adolescent (14-15 years) basketball players who were divided into two equal groups based on knee pain symptoms. Legs torque was tested on an isokinetic dynamometer. The length, elongation and the cross-sectional area (CSA) of the patellar tendon were measured with ultrasonography. Quadriceps angle (Q-angle), knee valgus motion, and joint angular displacement in the sagittal plane were analyzed using video recording during countermovement jump. Ground reaction force was measured using a force platform.
  
  
  RESULTS
  Knee pain (KP) participants had a significantly lower Q-angle (P=0.045) and lower maximum varus knee angle (P=0.035), and a greater knee inside displacement (P=0.039) during squat phase. In the KP group, the CSA at the top of the tendon was significantly greater than in the middle (P=0.006) and at the bottom (P=0.039). Absolute tendon stiffness (P=0.013) and Young's modulus (P=0.034) were significantly lower in the KP group compared with controls. Leg stiffness during landing was significantly greater in the control group (P=0.015).
  
  
  CONCLUSIONS
  Leg stiffness, valgus knee motion, and Q-angle are associated with hypertrophic soft patella tendon and idiopathic knee pain in adolescent basketball players.
authors.affiliation: Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania.
authors.forename: Danguole
authors.initials: D
authors.lastname: Satkunskiene
authors.affiliation: Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania.
authors.forename: Mantas
authors.initials: M
authors.lastname: Mickevicius
authors.affiliation: Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania - audrius.snieckus@lsu.lt.
authors.forename: Audrius
authors.initials: A
authors.lastname: Snieckus
authors.affiliation: Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania.
authors.forename: Sigitas
authors.initials: S
authors.lastname: Kamandulis
mesh_terms: D000293:Adolescent; D018771:Arthralgia / Q000209:etiology; D001490:Basketball / Q000502:physiology*; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D015444:Exercise; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D017847:Patellar Ligament / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000502:physiology; D014463:Ultrasonography