Navicular Drop Before and After Fatigue of the Ankle Invertor Muscles

Context: Navicular drop is widely believed to be an indicator of elevated susceptibility to pronation-related injuries, which may be increased by fatigue in the muscles that dynamically support the medial longitudinal arch. Objective: The purpose of this study was to evaluate navicular drop before and after fatigue of the ankle invertor muscles among individuals with different foot types. Participants: 20 male and 16 female recreationally active, college-age volunteers (20.03 +/- 1.48 years of age). Methods: Navicular drop was measured before and after inducing fatigue in the ankle invertor muscles. Participants' foot types were classified as high-arch, neutral, or low-arch. Results: There was no interaction between foot type and trial, and no main effect for trial. A main effect for foot type was significant (p = .001). Intra-class correlation coefficients for prefatigue and postfatigue measurements indicated good internal consistency. Conclusion: Our findings failed to provide any evidence to support the existence of a relationship between ankle invertor muscle fatigue and static measurements of change in navicular height from a sitting to standing position.