Muscle activation in the Gastrocnemius muscle is typically observed when the ankle joint is in dorsiflexion. In contrast, the Tibialis anterior muscle tends to be activated more when the ankle joint is in plantarflexion. These two muscles work synergistically, meaning they have complementary roles and can assist each other in specific movements or actions.
Passive movement can produce electrical activity in EMG recording even under anaesthesia. Obviously the resulting tracing is different from that obtained in an awake subject