2.3.3. Muscle performance
CONTRACTION
Muscle performance was assessed using a Biodex isokinetic dynamometer (Biodex Medical Systems, Shirley, NY). The system has shown good reproducibility in the healthy population [Testing began with a warm-up consisting of five repetitions at 60°/s including one movement at maximum voluntary contraction (MVC). Subsequently, the maximum force (Nm) was measured during three MVCs each at 60°/s and 180°/s. The highest measured value was retained. Endurance and power were measured over 15 MVC repetitions at 180°/s. Endurance was calculated as the total (sum) of strength developed during all 15 repetitions (Nm). Power was calculated (W) by multiplying the endurance value with the total time required for the patient to complete the repetitions; then divided by the number of repetitions (n = 15). For all tests, each maximum contraction was performed within the first 90 degrees of the knee’s range of motion.