title: Maximal Velocity as a Discriminating Factor in the Performance of Loaded Squat Jumps.
abstract: OBJECTIVE
  To determine what variables determine the differences in performance on 2 tests of squat jump (SJ) performed under light load in highly trained athletes using maximal velocity (Vmax) or flight time (FT) as the discriminating factor of SJ performance.
  
  
  METHODS
  Thirty-two participants performed 2 maximal weighted SJs using a force platform synchronized with a linear transducer. Mean force (Fmean), mean and maximal power (Pmean, Pmax), peak force (PF), maximal rate of force development (RFDmax), and time required to attain PF (TPF) and RFDmax (TRFDmax) were analyzed. SJs were divided into 2 segments: from the initiation of force application to PF1 and from the moment after PF1 to Vmax.
  
  
  RESULTS
  Traditional significance statistics revealed significant differences in the same variables between best and worst SJs using both FT and Vmax. However, to use an approach based on the magnitude of the effect, the best SJ showed greater Pmax (83/17/0%), Pmean (85/15/0%), Fmean (71/29/0%), RFDmax1 (73/27/0%), and PF1 (53/47/0%) and lower TPF2 (0/61/39%) than the worst SJ when Vmax was used to discriminate SJ performance. However, using FT to differentiate SJ performance, no difference was observed between best and worst.
  
  
  CONCLUSIONS
  Although jump height assessed through FT is a valid measure, these results suggest that Vmax is a more sensitive variable than FT to detect differences in loaded-SJ performance.
authors.affiliation: Department of Physical Activity and Sports Science, San Antonio de Murcia Catholic University, Murcia, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Jiménez-Reyes
authors.forename: Fernando
authors.initials: F
authors.lastname: Pareja-Blanco
authors.forename: David
authors.initials: D
authors.lastname: Rodríguez-Rosell
authors.forename: Mario C
authors.initials: MC
authors.lastname: Marques
authors.forename: Juan José
authors.initials: JJ
authors.lastname: González-Badillo
mesh_terms: D000328:Adult; D056352:Athletes; D054874:Athletic Performance / Q000502:physiology*; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D015444:Exercise; D005080:Exercise Test / Q000379:methods*; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D016474:Weight-Bearing; D055815:Young Adult