1) The study investigated the effects of three different strength training regimes on knee extensor and flexor strength in elite soccer players. 2) Only the high resistance training (4 sets, 8 reps at 8RM) induced increases in isokinetic muscle strength. 3) Concentric strength gains occurred at the training velocity, while eccentric strength gains occurred across all velocities tested. 4) The high resistance training augmented the capacity of the hamstrings to provide knee stability during fast extension.