Computer simulation of the effects of shoe cushioning on internal and external loading during running impacts

Abstract

Biomechanical aspects of running injuries are often inferred from external loading measurements. However, previous research has suggested that relationships between external loading and potential injury-inducing internal loads can be complex and nonintuitive. Further, the loading response to training interventions can vary widely between subjects. In this study, we use a subject-specific computer simulation approach to estimate internal and external loading of the distal tibia during the impact phase for two runners when running in shoes with different midsole cushioning parameters. The results suggest that: (1) changes in tibial loading induced by footwear are not reflected by changes in ground reaction force (GRF) magnitudes; (2) the GRF loading rate is a better surrogate measure of tibial loading and stress fracture risk than the GRF magnitude; and (3) averaging results across groups may potentially mask differential responses to training interventions between individuals.

Keywords:

• running injury
• computer simulation
• internal loading

Acknowledgements

The authors gratefully acknowledge Brian Umberger for advice and assistance in developing the model and Brent Edwards for comments on the manuscript. Funded by the American Society of Biomechanics graduate student grant-in-aid program. Readers interested in acquiring any of the codes, parameters, or data used in these simulations are encouraged to contact the corresponding author (RHM).