Dynamic in-vivo assessment of navicular drop while running in barefoot, minimalist, and motion control footwear conditions

- We investigated navicular drop in different footwear conditions.
- We compared static and dynamic measures of navicular drop.
- Footwear did not have a significant effect on the magnitude of navicular drop.
- Navicular drop rate was affected by footwear condition.
- The specific approach used in this study for assessing palpated ND may not be a strong predictor of radiographic ND.

Running-related injuries are common and previous research has suggested that the magnitude and/or rate of pronation may contribute to the development of these injuries. Accurately and directly measuring pronation can be challenging, and therefore previous research has often relied on navicular drop (under both static and dynamic conditions) as an indirect assessment of pronation. The objectives of this study were to use dynamic, biplane X-ray imaging to assess the effects of three footwear conditions (barefoot, minimalist shoes, motion control shoes) on the magnitude and rate of navicular drop during running, and to determine the association between static and dynamic measures of navicular drop. Twelve healthy distance runners participated in this study. The magnitude and rate of navicular drop were determined by tracking the 3D position of the navicular from biplane radiographic images acquired at 60 Hz during the stance phase of overground running. Static assessments of navicular drop and foot posture were also recorded in each subject. Footwear condition was not found to have a significant effect on the magnitude of navicular drop (p = 0.22), but motion control shoes had a slower navicular drop rate than running barefoot (p = 0.05) or in minimalist shoes (p = 0.05). In an exploratory analysis, static assessments of navicular drop and foot posture were found to be poor predictors of dynamic navicular drop in all footwear conditions (p > 0.18).