Orthotic control of rear foot and lower limb motion during running in participants with chronic Achilles tendon injury.
Donoghue OA, Harrison AJ, Laxton P, Jones RK. Sports Biomech. 2008 May;7(2):194-205
Think about it intuitivly ... what is the function of the muscles that pull on the achilles tendon? .... supinate and plantarflex the foot .... so if an orthotic is going to help, then it has to reduce the force in the tissues; ... ie it has to reduce the pronatory moments and the dorsiflexion moments .... it does not matter what it does to the motion ....its matters what it does to the forces
The 92% reduction in symptoms was not compared to a control group without orthotics, so any conclusion has to be tempered with that.
These had to be special orthoses equipped with pronation boosters. :rolleyes:
Pronation allows more dorsiflexion to occur in the midtarsal joint, so it would seem that we shouldn't make good orthoses for Achilles tendontitis.
Anecdotally, those runners with pronated feet and Achilles tendinitis/tendinosis who don't initially respond to heel lifts, stretching and icing seem to respond quite well to anti-pronation foot orthoses.
My assumption has always been that the orthosis must decrease the tensile stress on the injured/torn area of the Achilles tendon and therefore allows the pain to gradually resolve or the Achilles tendon to heal.
However, we still have no research yet, to my knowledge, that confirms this idea.