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.

All study participants receive a pair of custom made orthoses and perform daily calf-stretches. In addition to the orthoses two groups will perform tibialis posterior specific exercises; one as concentric and the second as eccentric activation. Intervention will last 12 weeks.

Inclusion Criteria:

• Pain (> 3 months duration)
• Pain localized to the medial ankle and foot
• Swelling at the medial ankle
• Able to perform a single controlled heel lowering

Exclusion Criteria:

• Bilateral posterior tibial tendon dysfunction
• Fixed foot deformities
• Previous foot surgery
• Presence of any other concurrent foot pathology besides posterior tibial tendon dysfunction
• Ability to walk only with assistive device
• Neurological disorders
• Cognitive dysfunction
• Uncontrolled cardiovascular disease
• Evidence of cord compression
• Uncontrolled hypertension
• Infection
• Severe respiratory disease
• Pregnancy
• Current or recent history of low back pain
• Known rheumatic joint disease
• Peripheral vascular disease with sensory loss of the foot.