Association Between Dynamic Strength Index Derived from Isometric Squat and Squat Jump or Countermovement Jump and Force-Velocity Profile

We investigated the associations and differences between dynamic strength index (DSI) calculated from different types of vertical jump (countermovement jump; CMJ and squat jump; SJ) and different isometric knee joint angles (30, 60 and 90 degrees), and associations with force-velocity (FV) profile and its constituent variables (maximal theoretical force (V-0), power (P-max) and velocity (V-0) and the slope of the FV relationship (S-fv), on a sample of young athletes and active participants (n = 28). There were moderate associations between P-max and all DSI values (r = 0.42-0.69; p < .05), V-0 and all DSI values from CMJ and DSI30 from SJ (r = 0.43-0.56; p < .05), while S-fv was associated only with DSI30 and DSI90 in CMJ (r = 0.40-0.43; p < .05). This suggests that DSI and FV methods provide similar information and can be used in a similar manner to direct an individual's training.