This study was undertaken to investigate whether differences exist in the coupling of foot and knee motions during the support phase of running in subjects with normal rearfoot motion and those who pronate. Excursion ratios between rearfoot eversion and tibial internal rotation were compared between the two groups. Timing between peak eversion, knee flexion, and knee internal rotation was also examined, and correlations between various foot and knee angles were assessed. Timings between peak knee and rearfoot angles were not significantly different between groups, although times were more closely matched in the normal subjects. The eversion to tibial internal rotation excursion ratio was significantly lower in the pronator subjects. Correlation analyses revealed significant relationships between a number of rearfoot and knee parameters. Results suggest that increased motion of the rearfoot can lead to excessive movement at the knee. In addition, excessive pronation may disrupt the normal kinematic interaction between the rearfoot and knee.