Posterior tibial tendon dysfunction (PTTD) is the most common cause of painful and debilitating acquired flatfoot deformity in adults. The dysfunction is often progressive and may result in attenuation of the PTT and eventually collapse of the plantar arch or even rupture of the tendon. Current therapeutic management of PTTD is multipronged and includes management with foot orthoses, stretching, and strengthening exercises. Evidence drawn from research related to the management of painful chronic Achilles tendinosis suggests that eccentric strengthening of the posterior tibialis may lead to superior results compared to concentric. The purpose of this research is to determine the effectiveness of treatment interventions used in the management of PTTD.