Effectiveness of an Individualized Training Based on Force-Velocity Profiling during Jumping

Ballistic performances are determined by both the maximal lower limb power output ( P _max ) and their individual force-velocity (F-v) mechanical profile, especially the F-v imbalance ( FV _imb ): difference between the athlete's actual and optimal profile. An optimized training should aim to increase P _max and/or reduce FV _imb . The aim of this study was to test whether an individualized training program based on the individual F-v profile would decrease subjects' individual FV _imb and in turn improve vertical jump performance. FVimb was used as the reference to assign participants to different training intervention groups. Eighty four subjects were assigned to three groups: an “optimized” group divided into velocity-deficit, force-deficit, and well-balanced sub-groups based on subjects' FV _imb , a “non-optimized” group for which the training program was not specifically based on FV _imb and a control group. All subjects underwent a 9-week specific resistance training program. The programs were designed to reduce FV _imb for the optimized groups (with specific programs for sub-groups based on individual FV _imb values), while the non-optimized group followed a classical program exactly similar for all subjects. All subjects in the three optimized training sub-groups (velocity-deficit, force-deficit, and well-balanced) increased their jumping performance (12.7 ± 5.7% ES = 0.93 ± 0.09, 14.2 ± 7.3% ES = 1.00 ± 0.17, and 7.2 ± 4.5% ES = 0.70 ± 0.36, respectively) with jump height improvement for all subjects, whereas the results were much more variable and unclear in the non-optimized group. This greater change in jump height was associated with a markedly reduced FV _imb for both force-deficit (57.9 ± 34.7% decrease in FV _imb ) and velocity-deficit (20.1 ± 4.3%) subjects, and unclear or small changes in P _max (−0.40 ± 8.4% and +10.5 ± 5.2%, respectively). An individualized training program specifically based on FV _imb (gap between the actual and optimal F-v profiles of each individual) was more efficient at improving jumping performance (i.e., unloaded squat jump height) than a traditional resistance training common to all subjects regardless of their FV _imb . Although improving both FV _imb and P _max has to be considered to improve ballistic performance, the present results showed that reducing FV _imb without even increasing P _max lead to clearly beneficial jump performance changes. Thus, FV _imb could be considered as a potentially useful variable for prescribing optimal resistance training to improve ballistic performance.