[Muscle exercise after the anterior cruciate ligament reconstruction of the knee--Part I: The force given to the anterior cruciate ligament by separate isometric contraction of the quadriceps or the hamstrings].

UNLABELLED

An attempt was made to investigate the force of the anterior cruciate ligament (ACL) in separate isometric contraction (IMC) of the quadriceps and the hamstrings by means of the analysis of two-dimensional models. In IMC of the quadriceps, the average value of the anterior drawer force (ADF) was equal to 14% of the quadriceps tension at the knee flexion of 5 degrees. The ADF decreased as the flexion angle increased. The average value of the angles, where the ADF became zero, was 45.3 degrees, and the standard deviation was 12.5 degrees. In IMC of the hamstrings, the posterior drawer force was given at the every flexion angle.

CLINICAL RELEVANCE

In the early stage of the rehabilitation after the ACL reconstruction, the quadriceps exercise by IMC should be performed at the knee flexion of more than 70 degrees (average + 1.96 X S.D.). The hamstrings exercise by IMC can be carried out regardless of flexion angle.