It is indirect, but calves are involved in squatting and deadlifting, so don't forget those as well. They will make sure you don't have twigs down low.
Also, prowler pushing/sled dragging hit the calves nicely and can be done often.
James 1:16-17 ESV
Do not be deceived, my beloved brothers. Every good gift and every perfect gift is from above, coming down from the Father of lights
With God's help...Mens sana in corpore sano