In a postural fault of pronation, which muscles need to be lengthened?

In the context of a postural fault of pronation, the muscles that typically become shortened are those of the calf, which includes the gastrocnemius and soleus. When the foot is in a pronated position, the tibialis anterior, which is responsible for dorsiflexion and inversion of the foot, can become lengthened or inhibited due to the excess motion and support loss from the excessively tight calf muscles.

Therefore, to correct a postural fault of pronation, it is crucial to focus on lengthening the muscles that are tight rather than those that are already in a lengthened position. The tibialis anterior, along with the soleus (which is actually referenced in the answer choice), needs to be reinforced in terms of strength to counter the influence of the tight gastrocnemius and soleus complex. In essence, by lengthening the muscles responsible for plantarflexion, you help restore a more neutral foot position, which is essential for proper alignment during movement.

The other choices involve muscles that do not play a primary role in addressing the issue of foot pronation, making them less relevant to the specific requirement of lengthening in this context.