title: Validity of a Simple Method for Measuring Force-Velocity-Power Profile in Countermovement Jump.
abstract: OBJECTIVE
  To analyze the reliability and validity of a simple computation method to evaluate force (F), velocity (v), and power (P) output during a countermovement jump (CMJ) suitable for use in field conditions and to verify the validity of this computation method to compute the CMJ force-velocity (F-v) profile (including unloaded and loaded jumps) in trained athletes.
  
  
  METHODS
  Sixteen high-level male sprinters and jumpers performed maximal CMJs under 6 different load conditions (0-87 kg). A force plate sampling at 1000 Hz was used to record vertical ground-reaction force and derive vertical-displacement data during CMJ trials. For each condition, mean F, v, and P of the push-off phase were determined from both force-plate data (reference method) and simple computation measures based on body mass, jump height (from flight time), and push-off distance and used to establish the linear F-v relationship for each individual.
  
  
  RESULTS
  Mean absolute bias values were 0.9% (± 1.6%), 4.7% (± 6.2%), 3.7% (± 4.8%), and 5% (± 6.8%) for F, v, P, and slope of the F-v relationship (SFv), respectively. Both methods showed high correlations for F-v-profile-related variables (r = .985-.991). Finally, all variables computed from the simple method showed high reliability, with ICC >.980 and CV <1.0%.
  
  
  CONCLUSIONS
  These results suggest that the simple method presented here is valid and reliable for computing CMJ force, velocity, power, and F-v profiles in athletes and could be used in practice under field conditions when body mass, push-off distance, and jump height are known.
authors.forename: Pedro
authors.initials: P
authors.lastname: Jiménez-Reyes
authors.forename: Pierre
authors.initials: P
authors.lastname: Samozino
authors.forename: Fernando
authors.initials: F
authors.lastname: Pareja-Blanco
authors.forename: Filipe
authors.initials: F
authors.lastname: Conceição
authors.forename: Víctor
authors.initials: V
authors.lastname: Cuadrado-Peñafiel
authors.forename: Juan José
authors.initials: JJ
authors.lastname: González-Badillo
authors.forename: Jean-Benoît
authors.initials: JB
authors.lastname: Morin
mesh_terms: D054874:Athletic Performance / Q000502:physiology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005080:Exercise Test / Q000379:methods / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D059385:Plyometric Exercise; D015203:Reproducibility of Results; D055815:Young Adult
keywords: force–velocity relationship; jumping; lower-limb explosive performance; resistance training