title: Validation of the iPhone app using the force platform to estimate vertical jump height.
abstract: BACKGROUND
  Vertical jump performance has been evaluated with several devices: force platforms, contact mats, Vertec, accelerometers, infrared cameras and high-velocity cameras; however, the force platform is considered the gold standard for measuring vertical jump height. The purpose of this study was to validate an iPhone app called My Jump, that measures vertical jump height by comparing it with other methods that use the force platform to estimate vertical jump height, namely, vertical velocity at take-off and time in the air.
  
  
  METHODS
  A total of 40 sport sciences students (age 21.4±1.9 years) completed five countermovement jumps (CMJs) over a force platform. Thus, 200 CMJ heights were evaluated from the vertical velocity at take-off and the time in the air using the force platform, and from the time in the air with the My Jump mobile application. The height obtained was compared using the intraclass correlation coefficient (ICC).
  
  
  RESULTS
  Correlation between APP and force platform using the time in the air was perfect (ICC=1.000, P<0.001). Correlation between APP and force platform using the vertical velocity at take-off was also very high (ICC=0.996, P<0.001), with an error margin of 0.78%.
  
  
  CONCLUSIONS
  Therefore, these results showed that application, My Jump, is an appropriate method to evaluate the vertical jump performance; however, vertical jump height is slightly overestimated compared with that of the force platform.
authors.affiliation: Faculty of Sport Sciences, University of Extremadura, Caceres, Spain - jorge.carlosvivas@gmail.com.|UCAM Research Center for High Performance Sport, Murcia, Spain - jorge.carlosvivas@gmail.com.
authors.forename: Jorge
authors.initials: J
authors.lastname: Carlos-Vivas
authors.affiliation: Faculty of Sport Sciences, University of Extremadura, Caceres, Spain.
authors.forename: Juan P
authors.initials: JP
authors.lastname: Martin-Martinez
authors.affiliation: Faculty of Sport Sciences, University of Extremadura, Caceres, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Hernandez-Mocholi
authors.affiliation: Faculty of Sport Sciences, University of Extremadura, Caceres, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Perez-Gomez
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D063731:Mobile Applications / Q000706:statistics & numerical data; D009068:Movement; D015203:Reproducibility of Results; D000068997:Smartphone / Q000706:statistics & numerical data*; D013334:Students / Q000706:statistics & numerical data; D055815:Young Adult