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.
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.
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.
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.
Young is with the Canadian Sport Institute Pacific, Victoria, BC, Canada. Haff, Newton, and Sheppard are with the Centre for Exercise and Sports Science Research, Edith Cowan University, Perth, Australia. Gabbett is with the School of Exercise Science, Australian Catholic University, Brisbane, Australia. Address author correspondence to Kieran Young at email@example.com.