Purpose: This pre-registered trial investigated how 6-weeks of unilateral flywheel leg curl and hip extension training impact isokinetic, isometric, and flywheel strength and power outcomes. Methods: The study involved 11 male university athletes (age 22 ± 2 years; body mass 77.2 ± 11.3 kg; height 1.74 ± 0.09 m) with one leg randomly allocated to flywheel training and one leg to control. Unilateral eccentric and isometric knee flexion torque and flywheel unilateral leg curl and hip extension peak power were tested. Training intensity and volume (3-4 sets of 6+2 repetitions) was progressively increased. Results: The intervention enhanced hip extension concentric (p < 0.01, d = 1.76, large) and eccentric (p < 0.01, d = 1.33, large) peak power more so than the control (significant interaction effect). Similarly, eccentric (p = 0.023, d = 1.05, moderate) peak power was enhanced for the leg curl. No statistically significant differences between conditions were found for isokinetic eccentric (p = 0.086, d = 0.77, moderate) and isometric (p = 0.431, d = 0.36, small) knee flexor strength or leg curl concentric peak power (p = 0.339, d = 0.52, small). Statistical parametric mapping analysis of torque-angle curves also revealed no significant (p > 0.05) time-limb interaction effect at any joint angle. Conclusion: Unilateral flywheel hamstring training improved knee flexor eccentric peak power during unilateral flywheel exercise but not flywheel concentric, isokinetic eccentric or isometric (long-lever) knee flexor strength.