Relationship between Medial Tibial Stress Syndrome and Mechanical Properties of the Posterior Lower Leg Muscles

Abstract

Medial tibial stress syndrome (MTSS) is considered to be a microinjury at the junction of the tibial periosteum and fascia. The most common site affected by MTSS is the attachment of flexor digitorum muscle to the posteromedial border of tibia. The development of MTSS could be related to the mechanical properties of the toe flexor muscles, namely strength and muscle stiffness. In addition, a history of MTSS is a risk factor for its relapse, suggestive of some physical factors associated with MTSS development in runners with a history of MTSS. Therefore, we investigated these physical factors of the posterior lower leg muscle such as strength and stiffness in runners with a history of MTSS, who did not have pain in the lower limbs on the day of measurement, using a newly developed toe flexor strength measuring device and shear wave elastography. The results showed that the runners with a history of MTSS had higher stiffness in flexor digitorum longus and tibialis posterior muscles and increased plantar flexor strength of the first metatarsophalangeal joint, suggesting an association between MTSS and the mechanical properties of the toe flexor muscles.