They report that the medial gastrocnemius displayed superior muscle activity when performing plantarflexion with an extended knee position, while the soleus displayed superior muscle activity with the leg bent. (strengthandconditioningresearch.com)
They report that when performing plantarflexion with the knee fully extended, the medial and lateral gastrocnemius displayed superior peak muscle activity with increasing angular velocity, while the soleus displayed decreasing peak muscle activity with increasing velocity. (strengthandconditioningresearch.com)
Therefore, it appears that performing ankle plantarflexion exercises including the bottom range (dorsiflexion) is beneficial for the calf muscles. (strengthandconditioningresearch.com)