What is antagonist to tibialis anterior?

The antagonist of tibialis anterior is the gastrocnemius muscle group, located in the posterior calf region. The gastrocnemius muscle group consists of two muscles, the medial and lateral heads, and is responsible for plantarflexion of the foot, or pointing the toes downward. When the gastrocnemius muscle contracts, it works against the tibialis anterior muscle, which is responsible for dorsiflexion, or lifting the foot upward. During some movements, both muscles may work together, but overall they have opposite actions and are considered antagonists.