Final answer:
An excessively pronated foot is due to poor activation of the Tibialis anterior muscle in the leg.
Step-by-step explanation:
An overly pronated foot is due to poor activation of the Tibialis anterior muscle. The Tibialis anterior muscle is located in the anterior compartment of the leg and is responsible for raising the front of the foot when it contracts. When the Tibialis anterior is weak or not activating properly, it can lead to excessive pronation of the foot, which is an inward rolling of the foot.