ARCH-TYPE AND SHOE INTERACTIONS DURING RUNNING

Abstract

The purpose of this study was to examine the interaction of foot arch-type and running shoe midsole hardness on lower extremity mechanics. Ground reaction forces {GRF) and kinematic timing variables were examined during the support phase of overground running. Eighteen healthy, male, recreational runners served as subjects. They completed 15 running trials in two different shoes; 1) a soft midsole shoe and 2) a hard midsole shoe. Foot type was quantified using a Tekscan pressure mat. From the pressure data, a ratio of forces on the midfoot to the forces an the entire foot was generated to categorize runners as high arched, normal arched and flat arched. Three dimensional kinematic data were collected using three 200 Hz high speed video cameras. Ground reaction force data were collected at 1 000 Hz using an AMTI force platform. Significant differences were found between shoe conditions for 5 GRF parameters (p < 0.05). No significant differences were found between arch types for any of the GRF parameters ( p < 0.05). In addition, no significant differences were found between shoe conditions or between arch types for any of the kinematic timing parameters @ < 0.05). However a significant interaction was observed between shoe conditions and arch groups for total support time and for the percent time to maximum femoral rotation. Results of the study indicated that force ratio footprints was an ineffective method of predicting either kinematic or kinetic changes in running mechanics.