[Muscle exercise after anterior cruciate ligament reconstruction of the knee--Part II: The development of the exercise method by simultaneous isometric contraction of the quadriceps and the hamstrings, and its biomechanics].

UNLABELLED

An attempt was made to investigate the stress of the ACL in the simultaneous isometric contraction (IMC) of the quadriceps and the hamstrings by means of analysis of two-dimensional models, and to estimate electromyographically the forces of those muscles in that contraction. The anterior drawer force (ADF) in the simultaneous IMC decreased as the flexion angle of the knee increased. The average value of the angles, where the ADF became zero, was 7.4 degrees. The integrated EMGs of the quadriceps and the hamstrings in the simultaneous maximum IMC were equal to 30-60% of those in separate maximum IMC.

CLINICAL RELEVANCE

In the early stage of the rehabilitation after the ACL reconstruction, the simultaneous IMC of the quadriceps and the hamstrings is useful as one of the muscle exercise method, because that can be performed at the knee position near the full extension and can generate sufficient muscle force for exercise.