1000 mg L-carnitine with 3000 mg L-leucine per day for 24 weeks

4000 mg L-leucine per day for 24 weeks

vastus lateralis muscle biopsy taken before and after the supplementation procedure (~20 cm proximal to the knee joint using a thin biopsy needle); carnitine concentration determined using ultra performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS) method

Peak torque measured by performing maximum voluntary contractions during isometric knee extension and flexion. The test performed in concentric-concentric mode consisting maximum 4-s knee extensor isometric contraction and maximum 4-s knee flexor isometric contraction, separated by 20-s recovery, repeated three times. Muscle isokinetic strength assessed in 5 repetitions of flexion and extension at a speed of 60°/s. Muscle endurance assessed in 10 repetitions at 300°/s determine the ability of the muscle to maintain the work. Strength testing performed on the Biodex System 4 Pro dynamometer.