Running in new and worn shoes: a comparison of three types of cushioning footwear.

OBJECTIVES

In this study, the effect of shoe degradation on running biomechanics by comparing the kinetics and kinematics of running in new and worn shoes was investigated. Three types of footwear using different cushioning technologies were compared.

DESIGN

Longitudinal study.

SETTING

Pre- and post-tests on overground running at 4.5 m s(-1) on a 20-m laboratory runway; performance measured using a force platform and a motion capture system.

PARTICIPANTS

24 runners (14 men and 10 women)

INTERVENTIONS

200 miles of road running in the same pair of shoes. Within-group factor: shoe condition (new/worn); between-group factor: footwear type (air/gel/spring).

MAIN OUTCOME MEASUREMENTS

Stance time was calculated from force data. External loads were measured by maximum vertical force and loading rate. Kinematic changes were indicated by sagittal plane angles of the torso, hip, knee and ankle at critical events during the stance phase.

RESULTS

Stance time increased (p=0.035) in worn shoes. The torso displayed less maximum forward lean (p<0.001) and less forward lean at toe-off (p<0.001), while the ankle displayed reduced maximum dorsiflexion (p=0.013) and increased plantar flexion at toe-off (p<0.001) in worn shoes. No changes in the hip and knee angles. No between-group difference among the three footwear groups or condition by type interaction was found in any measured variables.

CONCLUSIONS

As shoe cushioning capability decreases, runners modify their patterns to maintain constant external loads. The adaptation strategies to shoe degradation were unaffected by different cushioning technologies, suggesting runners should choose shoes for reasons other than cushioning technology.