Are the Forces and Lower Limb Kinematics Displayed During Running Associated with Medial Tibial Stress Syndrome? A Case-Control and Case Study

Objectives: The aim of this paper is to determine whether leg kinematics and the normal force generated during the stance phase of running differed between (i) long-distance runners with medial tibial stress syndrome (MTSS) or (ii) long-distance runners who were asymptomatic at baseline testing but developed MTSS compared to asymptomatic control participants. Methods: Lower-limb kinematics, normalised stance-phase forces and spatiotemporal outcome variables were compared between the limbs of MTSS symptomatic long-distance runners (n = 11) and matched asymptomatic controls (n = 11). Outcome variables were also compared between the limbs of long-distance runners who were asymptomatic at baseline but developed MTSS (n = 4) compared to asymptomatic control limbs. Results: In the case-control comparison, MTSS symptomatic participants demonstrated slower running speeds but no differences in stance-phase normal forces or kinematics compared to asymptomatic controls. In the case study, participants who developed MTSS during the study displayed substantially lower normal forces, less plantar flexion and a more vertical tibia than the asymptomatic controls. Conclusions: The slower running speeds observed among the MTSS symptomatic participants may be pain-related or reflect reduced plantar flexor propulsive capacity. The development of MTSS by Participants 1 and 2, despite lower normal forces and plantar flexion compared with asymptomatic controls, suggests that the tibial load tolerance may vary among individuals. Furthermore, the peak stance-phase force appears to have limited utility as a standalone screening tool for MTSS injury risk. Finally, further prospective research is required to investigate plantar flexor function, propulsive force capacity and the risk of MTSS development to substantiate these findings.