Running Characteristics of Plantar Flexor Forces Based on Different Foot Strike Patterns in Medial Tibial Stress Syndrome

OBJECTIVES The purpose of this study was to compare plantar flexor force due to different foot strike patterns during running in barefoot and shod condition with and without medial tibial stress syndrome (MTSS).METHODS Fifteen collegiate soccer players who volunteered to participate were divided into MTSS group and controls. Participants’ running at 3.3 m/s with and without shoes were recorded with a 12-camera system at a sampling frequency of 250 Hz. Each subject completed different foot strike patterns of running as the forefoot strike pattern (FFS) and rearfoot strike pattern (RFS) were collected. Plantar flexor forces were investigated by software for interactive musculoskeletal modeling.RESULTS Normalized plantar flexor forces in barefoot running with the FFS pattern had greater soleus and peroneus brevis muscle forces in the MTSS group than in controls during the first half of stance, although there were no statistically significant differences for other plantar flexor muscle forces between groups and shod running. In plantar flexor forces due to foot strike pattern, the FFS pattern showed higher plantar flexor forces than the RFS pattern.CONCLUSIONS The results of musculoskeletal modeling suggest that subjects with MTSS have greater muscle forces of the plantar flexor during running, especially barefoot running with the FFS pattern. It also suggests increased forces in some plantar flexors generated great traction force by repetitively landing on connective tissues in the deep crural fascia causing inflammation at the posteromedial site of the tibia in MTSS.