Achilles tendinosis, different than Achilles tendonitis, is actually a degenerative condition in which the tendon shows NO SIGNS of inflammation and swelling. It's believed that tendinosis results as a failure of the tendon to respond to repetitive trauma overtime in which there is an imbalance between the body's ability to make new tendon cells vs degeneration of old tendon cells. The area where the pain is felt differentiates insertional (heel) vs mid-portion (middle of the tendon) Achilles tendinosis. . When it comes to physical therapy management of Achilles Tendinosis, and program focused on progressive loading of the tendon, in addition to proximal glute/core strengthening and heel cord stretching should be implemented. These exercises are just a sample of many that can be used in a comprehensive treatment program. Loading the tendon promotes tendon healing by essentially "re-injurying" the tendon and forcing the body to re-ignite the healing process. It's counter-intuitive at first, but the body is AMAZING at adapting to new stimuli and stresses, and by progressively overloading what the tendon can handle, we can tap into the body's amazing healing powers to "heal itself". . If the tendon is extremely painful, first start with isometrics. There is a analgesic effect to contracting your muscles, similar to why it feels good to shake or rub your toe when you stub it. Next, transition into eccentric strengthening, which gets the benefit of also lengthening of the muscle-tendon unit and thus "stretching while strengthening". Next, move into any form of high-load exercises for the Achilles tendon regardless of concentric vs eccentric contraction. Remember, it’s the volume of load that is important and the use of certain types of muscle contractions is used in an attempt to bypass any pain with the exercises! . Shoot for 3 sets of 15, to be performed everyday, of the eccentric calf raises to start out. If there is a bit of discomfort while doing it - it's fine. Tendinosis is one of the few conditions in which it's fine if there is a bit of discomfort as the tendon needs to be strengthened. Happy tendon strengthening!