PURPOSE: To assess and compare torque and electromyographic activity of the vastus lateralis and biceps femoris muscles upon knee extension and flexion in open kinetic chain. METHODS: Fifteen male subjects were distributed in two groups: Test Group (TG) (32.2 ± 7.1 years) composed by five subjects who had previously been submitted to anterior cruciate ligament arthroscopic reconstruction (patellar tendon); and Control Group (CG) (30.1 ± 10.7 years) composed by ten uninjured subjects. Data acquisition was performed using Cybex 6000 at 100°.s-1; 10 seconds of electromyography data were obtained using active differential electrodes (Delsys-Bagnoli 8) at a sample rate of 1000 Hz. Root Mean Square (RMS) values and temporal pattern of muscles activation based on movement phase were considered (linear envelope). RESULTS: Injured legs showed greater flexor peak torque and smaller extension peak torque; greater agonist activation and smaller antagonist activation for the biceps femoris muscle, and smaller agonist activation for the vastus lateralis muscle. Linear envelope showed that test group showed smaller vastus lateralis muscle activation comparing to control group. CONCLUSION: Despite the rehabilitation period, injured legs still showed extensor torque deficit, which may explain the remaining complains presented by anterior cruciate ligament reconstructed subjects.
Anterior Cruciate Ligament; Physical therapy; Electromyography; Biomechanics; Knee
