title: Influence of Isoinertial-Pneumatic Mixed Resistances on Force-Velocity Relationship.
abstract: OBJECTIVE
  Muscle strengthening is commonly based on the use of isoinertial loading, whereas variable resistances such as pneumatic loading may be implemented to optimize training stimulus. The purpose of the current study was to determine the effect of the ratio between pneumatic and isoinertial resistance on the force-velocity relationship during ballistic movements.
  
  
  METHODS
  A total of 15 participants performed 2 concentric repetitions of ballistic bench-press movements with intention to throw the bar at 30%, 45%, 60%, 75%, and 90% of the maximal concentric repetition with 5 resistance ratios including 100%, 75%, 50%, 25%, or 0% of pneumatic resistance, the additional load being isoinertial. Force-, velocity-, and power-time patterns were assessed and averaged over the concentric phase to determine the force-velocity and power-velocity relationships for each resistance ratio.
  
  
  RESULTS
  Each 25% increase in the pneumatic part in the resistance ratio elicited higher movement velocity (+0.11 ± 0.03 m/s from 0% to 80% of the concentric phase) associated with lower force levels (-43.6 ± 15.2 N). Increased isoinertial part in the resistance ratio resulted in higher velocity toward the end of the movement (+0.23 ± 0.01 m/s from 90% to 100%).
  
  
  CONCLUSIONS
  The findings show that the resistance ratio could be modulated to develop the acceleration phase and force toward the end of the concentric phase (pneumatic-oriented resistance). Inversely, isoinertial-oriented resistance should be used to develop maximal force and maximal power. Resistance modality could, therefore, be considered an innovative variable to modulate the training stimulus according to athletic purposes.
authors.forename: Simon
authors.initials: S
authors.lastname: Avrillon
authors.forename: Boris
authors.initials: B
authors.lastname: Jidovtseff
authors.forename: François
authors.initials: F
authors.lastname: Hug
authors.forename: Gaël
authors.initials: G
authors.lastname: Guilhem
mesh_terms: D000328:Adult; D006801:Humans; D008297:Male; D009068:Movement; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D055070:Resistance Training / Q000379:methods*; D014891:Weight Lifting / Q000502:physiology; D055815:Young Adult
keywords: constant load; exercise modality; maximal power; variable resistance