The calf, soleus, and Achilles tendon (triceps surae) are attached to the calcaneus (heel bone), to which the plantar fascia is attached, which in turn is attached to the base of the toes. Every part is connected like a chain. If one is tight, they are all too tight. As we age the calf gradually and usually silently contracts (separate discussion as to why) to the point where it reaches a critical point of tension, usually in the 40’s and later. While a tight calf mechanically creates a multitude of pathologic forces in the foot and ankle, the plantar fascia seems to be the first and most frequent area to become symptomatic because it is what I have termed “the weak link in the chain”. The maximal tension in gait is reached at the middle of mid stance, as the opposite or swing phase foot passes the stance phase or symptomatic foot, giving way to the characteristic startup limp in the morning or getting up from sitting during the day, etc. The reason plantar fasciitis is so difficult to treat is that everyone is looking in the wrong places and treating the wrong thing, the heel. The problem is in the calf, not the heel. This has openly been my mantra for 25 years. A few of my colleagues, over the past few years, have finally started to understand this relationship, publishing evidence to this claim that the calf is too tight.
Stretch your calves. Save your feet.
Plantar fasciitis mechanics animation from One Stretch on Vimeo.