title: Assessment and monitoring of ballistic and maximal upper-body strength qualities in athletes.
abstract: OBJECTIVE
  To evaluate whether the dynamic strength index (DSI: ballistic peak force/isometric peak force) could be effectively used to guide specific training interventions and detect training-induced changes in maximal and ballistic strength.
  
  
  METHODS
  Twenty-four elite male athletes were assessed in the isometric bench press and a 45% 1-repetition-maximum (1RM) ballistic bench throw using a force plate and linear position transducer. The DSI was calculated using the peak force values obtained during the ballistic bench throw and isometric bench press. Athletes were then allocated into 2 groups as matched pairs based on their DSI and strength in the 1RM bench press. Over the 5 wk of training, athletes performed either high-load (80-100% 1RM) bench press or moderate-load (40-55% 1RM) ballistic bench throws.
  
  
  RESULTS
  The DSI was sensitive to disparate training methods, with the bench-press group increasing isometric bench-press peak force (P=.035, 91% likely), and the ballistic-bench-throw group increasing bench-throw peak force to a greater extent (P≤.001, 83% likely). A significant increase (P≤.001, 93% likely) in the DSI was observed for both groups.
  
  
  CONCLUSIONS
  The DSI can be used to guide specific training interventions and can detect training-induced changes in isometric bench-press and ballistic bench-throw peak force over periods as short as 5 wk.
authors.affiliation: Canadian Sport Institute Pacific, Victoria, BC, Canada.
authors.forename: Kieran P
authors.initials: KP
authors.lastname: Young
authors.forename: G Gregory
authors.initials: GG
authors.lastname: Haff
authors.forename: Robert U
authors.initials: RU
authors.lastname: Newton
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Gabbett
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Sheppard
mesh_terms: D000293:Adolescent; D000328:Adult; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D055070:Resistance Training / Q000379:methods*; D034941:Upper Extremity / Q000502:physiology*; D014891:Weight Lifting / Q000502:physiology*; D055815:Young Adult