Subjects with injury of the anterior cruciate ligament (ACL) have shown relevant functional alterations in the knee muscles. Therefore, it is extremely important to characterize these alterations, as well as to emphasize an efficient rehabilitation protocol for these subjects and consequently return them to physical activities. The purpose of this study was to investigate the medium frequency (Fmed) of the electromyographic signal in ACL subjects with lesions during isometric exercises in open (OKC) and closed kinetic chain (CKC). Forty subjects (with and without lesion) performed knee extension during maximal voluntary isometric contraction on Leg Extension and Leg Press at 30º, 60º and 90º of knee flexion. The results showed smaller Fmed values for ACL deficient subjects when compared with counter lateral and control groups in OKC exercises (p<0,05). However, there was not significant difference in CKC exercises between groups (p>0,05), not showing thus, this kind of injury. Therefore, the Fmed can be considered an efficient tool in the LCA injury characterization. Moreover, CKC exercises seem to be the best alternative for rehabilitation of the ACL deficient subjects.
Knee; Electromyography; Rehabilitation
