Post from the gait guys on risk for achilles tendon pain relating to ankle dorsiflexion, or the ability to bring your toes toward your shin. Limited ankle dorsiflexion is a major contributor to several common musculoskeletal problems and a part of my standard biomechanical screening. Detailed observation is required though, small deviations in the arch of the foot can mask the tightness and poor stretching or exercise form fails to get into the restriction.
The achilles has an odd way of twisting into the insertion site at the heel, turning 90 degrees as it goes into the bone, if the arch is not controlled from the rest of the foot and leg musculature, the tricep surae, or calves, might try and control it through this twist, leading to double duty and overuse
credit Michaud – Human Locomotion – great textbook