title: Immediate effects of whole body vibration on patellar tendon properties and knee extension torque.
abstract: OBJECTIVE
  Reports about the immediate effects of whole body vibration (WBV) exposure upon torque production capacity are inconsistent. However, the changes in the torque-angle relationship observed by some authors after WBV may hinder the measurement of torque changes at a given angle. Acute changes in tendon mechanical properties do occur after certain types of exercise but this hypothesis has never been tested after a bout of WBV. The purpose of the present study was to investigate whether tendon compliance is altered immediately after WBV, effectively shifting the optimal angle of peak torque towards longer muscle length.
  
  
  METHODS
  Twenty-eight subjects were randomly assigned to either a WBV (n = 14) or a squatting control group (n = 14). Patellar tendon CSA, stiffness and Young's modulus and knee extension torque-angle relationship were measured using ultrasonography and dynamometry 1 day before and directly after the intervention. Tendon CSA was additionally measured 24 h after the intervention to check for possible delayed onset of swelling.
  
  
  RESULTS
  The vibration intervention had no effects on patellar tendon CSA, stiffness and Young's modulus or the torque-angle relationship. Peak torque was produced at ~70° knee angle in both groups at pre- and post-test. Additionally, the knee extension torque globally remained unaffected with the exception of a small (-6%) reduction in isometric torque at a joint angle of 60°.
  
  
  CONCLUSIONS
  The present results indicate that a single bout of vibration exposure does not substantially alter patellar tendon properties or the torque-angle relationship of knee extensors.
authors.affiliation: Department of Sport Science and Kinesiology, University of Salzburg, Rifer Schlossallee 49, 5400, Hallein/Rif, Austria. florian.rieder@sbg.ac.at.
authors.forename: F
authors.initials: F
authors.lastname: Rieder
authors.affiliation: Department of Sport Science and Kinesiology, University of Salzburg, Rifer Schlossallee 49, 5400, Hallein/Rif, Austria.
authors.forename: H-P
authors.initials: HP
authors.lastname: Wiesinger
authors.affiliation: Department of Sport Science and Kinesiology, University of Salzburg, Rifer Schlossallee 49, 5400, Hallein/Rif, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Kösters
authors.affiliation: Department of Sport Science and Kinesiology, University of Salzburg, Rifer Schlossallee 49, 5400, Hallein/Rif, Austria.
authors.forename: E
authors.initials: E
authors.lastname: Müller
authors.affiliation: Department of Physical Performance, Norwegian School of Sport Sciences, Sognsveien 220, Ullevål stadion, P.O. Box 4014, 0806, Oslo, Norway.
authors.forename: O R
authors.initials: OR
authors.lastname: Seynnes
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004548:Elasticity; D005260:Female; D006801:Humans; D007717:Knee / Q000502:physiology*; D008297:Male; D009068:Movement; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000502:physiology; D017847:Patellar Ligament / Q000502:physiology*; D016059:Range of Motion, Articular; D019415:Torque; D014732:Vibration / Q000009:adverse effects*
keywords: Length–tension relationship; Material properties; Mechanical properties; Strength