When testing Tibialis Posterior strength, what action should the patient perform?

To effectively test the strength of the Tibialis Posterior muscle, the patient should perform inversion of the foot with slight plantarflexion. Tibialis Posterior is primarily responsible for inverter and also assists in plantarflexion of the foot at the ankle.

Inversion involves turning the sole of the foot inward, which is a key action of the Tibialis Posterior as it helps support the medial arch of the foot and contributes to stability during dynamic movements. Incorporating slight plantarflexion in the test allows for a more comprehensive evaluation of the muscle's strength, as both functions are engaged during typical activities, such as walking or running.

This combination of movements accurately reflects the real-life actions the Tibialis Posterior performs, providing a good gauge of its strength and functionality. Thus, having the patient perform inversion with slight plantarflexion is essential for assessing the muscle effectively and is the correct approach for this strength test.