Acquired calf shortening is a condition most common in women who regularly wear heels higher than 2.5 cm, let’s think Barbie. There is a seen in the latest Barbie movie in which she steps out of her shoes and her feet are still perfectly arched and she walks off on her toes. t is also seen as some people do have congenital short soleus and Achilles tendon.
The shortening of the calf muscles increases the mechanical loading parameters on the mid-foot (known as secondary unlocking). These are the people who cannot get their heels down when they are in Pike or a downward dog. If the person overstretches the calf, keeps having acupuncture or stresses the tendons so much then they can rupture the Achilles.
When working with this group of people the first instinct is to stretch the calf. You will find that these are the people constantly looking for a stretch to release the calf muscles but it never quite stays stretched out. Rather than just stretching and stretching, you might find that you need to encourage the person to moderate their footwear (good luck with that one). When they are doing exercise, whether it be pilates, yoga, or running, they have a small support that allows their calf muscles to still be shortened but not as shortened as they are used to, e.g. have them do standing work with a folded slip mat under their heels. These people are often helped by orthotics that support their mid-foot.