Inter-relationship between rearfoot and midfoot frontal plane motion during walking

Background: Because of the complex nature of foot motion during locomotion, the relationship between the rearfoot and midfoot warrants additional investigation. Objective: Explore the relationship between frontal plane motion of the rearfoot and midfoot during the stance phase of walking. Method: Using an electromagnetic motion analysis system, the frontal plane motion of the rearfoot and midfoot of 153 individuals (55 men, 98 women) were collected. The resulting motion patterns for each segment of the foot were then correlated to determine if all subjects exhibited the same relationship between the two segments. Those subjects with a statistically significant negative correlation between the rearfoot and midfoot were then compared on eight rearfoot variables with the group of subjects with a statistically significant positive correlation. Results: The mean correlation between the rearfoot and midfoot segments was found to be -.307 with a standard deviation of .094. Counter-rotation between the rearfoot and midfoot segments was not seen in 18.9% of the subjects. Conclusions: This study indicates that a significant group of individuals do not demonstrate the typical counter-rotation pattern of motion between the rearfoot and midfoot during walking. Possible reasons for and the likely clinical implications of this atypical motion pattern are discussed.