To lengthen and relax the muscles at the back of the lower leg.
Stand facing a wall with both palms flat against the surface at roughly shoulder height. With both feet facing directly forwards, place the foot of the affected side roughly 12-18 inches behind the unaffected foot. Ensure that the heel of the affected foot is completely in contact with the floor.
Slowly and in a controlled manner, lean towards the wall by bending the knee of the front leg in a lunge movement. Be sure to keep the heel of the back foot firmly grounded at all times, and that same leg completely stretched. When a stretch is felt at the back of the affected calf, hold the position for 30 seconds whilst breathing slowly and deeply. Return to starting position and repeat on the other side.
To create a stretch lower in the calf (more specific to the Soleus muscle) allow the knee of the back leg to also bend and drop downward into the stretch rather than forwards. When a stretch is felt, hold the position for 30 seconds whilst breathing slowly and deeply before returning to start position.
The calf muscles can also be stretched by placing the ball and toes of the foot on the edge of a step and allowing the heel to drop down using your own body weight.