This quasi-experimental study examined the immediate effects of short-foot exercise (SFE) on peak soleus activation and hindfoot eversion in runners with medial tibial stress syndrome (MTSS), and compared these parameters with asymptomatic runners. Thirty-two participants (16 MTSS, 16 controls) performed SFE, with electromyography and 3D kinematic data collected at various running speeds. Results showed that SFE significantly reduced peak soleus activation in both groups, indicating improved neuromuscular efficiency and potential reduction in tibial stress. No significant change in hindfoot eversion was observed. A strong correlation was found between ankle dorsiflexion and muscle activation. Findings support SFE as a beneficial strategy for enhancing neuromuscular function and managing tibial stress in runners.