Which muscle is antagonistic to the Gmed? The answer is the adductors, and if there is an underlying factor that causes the adductors to become tight and shortened (such as trigger points), this might in turn be a causative factor for weakness of the Gmed posterior fibers.

If the adductors are short, they are generally in a hypertonic state. In this case, when we contact the ground during the gait cycle, the main stabilizing muscle of the lateral sling should be the Gmed, as this also keeps the alignment of the pelvis.

Compensation Patterns

If the adductors receive more neural stimulus from the obturator nerve (as when the adductors have become the main stabilizing muscle instead of the Gmed), this compensation pattern will naturally take the hip into an increased medial rotation, adduction, and hip flexion.

As a result, the knee drifts medially (valgus position) because of the increased medial rotation of the femur caused by the hypertonic adductors and the weakened Gmed.

As this compensation pattern continues it can be precursory to loading of the MCL and the underlying attachment to the medial meniscus because of the altered biomechanics.

Moreover, the lateral meniscus can also be involved owing to a compressive force caused by the increased valgus position of the knee.

Adductor Magnus - Common trigger point sites

Lateral Knee Drift

Because of the varus position, lateral knee drift is rarely seen in the sports injury clinic. There is limited information in the literature about this condition and many physical therapists may not be aware of it.

Lateral knee drift can be observed in a patient performing a single-leg squat if they have a weakness in their Gmed or Gmax. It can also occur when an athlete is running and they have an anterior-tilted pelvis with a forward trunk position. At heel-strike the knee can be forced into a lateral shift so that the

Gmed is offloaded and the foot/ankle is forced into a more supinated position.

This excessive lateral drift of the knee will place increased strain on the medial meniscus because of the increased compression of the varus position; it can also overload the ITB and the popliteus muscle.

About the Author

This trigger point therapy blog is intended to be used for information purposes only and is not intended to be used for medical diagnosis or treatment or to substitute for a medical diagnosis and/or treatment rendered or prescribed by a physician or competent healthcare professional. This information is designed as educational material, but should not be taken as a recommendation for treatment of any particular person or patient. Always consult your physician if you think you need treatment or if you feel unwell.