The aims of this study are to: (1) determine muscle activation of the tibialis posterior muscle during different common gastrocnemius stretches and (2) radiographically quantify the tibial-calcaneal angle during the common stretching positions. We hypothesize that stretching over the edge of a step with the arch supported will minimize the activation of the tibialis posterior muscle in addition to increasing the tibial-calcaneal angle.

Many studies have assessed the effect of dynamic and passive support of the medial longitudinal arch. The posterior tibial tendon is the main dynamic stabilizer of the medial longitudinal arch, although peroneus/fibularis longus, flexor digitorum longus, and flexor hallucis longus also contribute to a lesser degree. Passive structures also a play role in supporting the arch and include the plantar fascia, plantar ligaments and spring ligament. These plantar structures aid in preventing collapse of the arch during weight bearing.

Several studies have demonstrated that increased tension from the triceps surae can lead to flattening of the arch. Gastrocnemius muscle tightness in particular is thought to be partially responsible for many forefoot and midfoot conditions in non-neurologically impaired patients. Therefore, identifying effective ways to stretch the gastrocnemius muscle without creating increased stress through dynamic structures that support the longitudinal arch may be important for the management of individuals with limited gastrocnemius flexibility.

Common ways to stretch the gastrocnemius include a runner's stretch, stretching with the foot fully supported on a ramp, stretching with the arch of the foot supported on the edge of step and the heel dropping down toward the ground and lastly, stretching with the ball of the foot supported on the edge of a step and the heel dropping down toward the ground. To our knowledge no other studies have assessed the muscle activation of the tibialis posterior muscle via indwelling EMG activation in addition to radiographic measurements to determine the effectiveness of common gastrocnemius stretches. Therefore, the aims of this study are to determine muscle activation of the tibialis posterior muscle during different common gastrocnemius stretches and to radiographically quantify the tibial-calcaneal angle. We hypothesize that stretching over the edge of a step with the arch supported will minimize the activation of the tibialis posterior muscle in addition to increasing the tibial-calcaneal angle more than the other stretching positions.

Inclusion Criteria:

• 20 healthy subjects between the ages of 18 to 65 years old.

Exclusion Criteria:

• any boney or tendinous foot/ankle operative procedure
• diagnosis of neuromuscular disorder
• any previous ankle fracture or degenerative changes that would limit dorsiflexion range of motion
• no obvious gait asymmetries demonstrated through observation
• participants who are pregnant will be excluded from participation in the study

Healthy individuals