Does calf muscle morphology and function differ between mtss symptomatic and asymptomatic long-distance runners?

We aimed to determine whether calf muscle morphology or function differed between medial tibial stress syndrome (MTSS) symptomatic and asymptomatic long-distance runners. Muscle thickness and strength of the superficial posterior lower leg compartment and calf muscle endurance were assessed for 8 symptomatic runners and 8 asymptomatic matched controls. Although symptomatic runners displayed a significantly thicker gastrocnemius and a trend towards reduced calf muscle endurance, there was no significant between-group difference in lean calf girth or strength of the gastrocnemius and soleus muscles. We speculate that the deep ankle plantar flexors likely play a pivotal role in modulating tibial loading and MTSS development.