Training programmes incorporating isoinertial technology have contributed to a considerable improvement in developing muscle force and muscle power. Objectives: to evaluate knee flexor and extensor muscle force in concentric and eccentric contractions. Method: A 4-week training programme (3 sessions/week) using isoinertial technology was implemented, involving simultaneous flexion and extension of both knees. Before and after the training programme, lower-body power was evaluated using "VersaPulley" isoinertial technology in separate knee extension and flexion exercises. Data for power, velocity, force, work, repetition times etc. were recorded and monitored for both concentric and eccentric contractions. Results: Significant improvement (p=0.05) was recorded for both concentric and eccentric contractions in knee flexion and extension. Conclusions: In the early stages of functional recovery, general exercise enhances adaptation between limbs, reducing the asymmetry prompted by sports injuries. In the course of physical recovery, the overload caused by working separately with the affected limb is diminished, thus shortening recovery time.