Differences in static and dynamic measures in evaluation of talonavicular mobility in gait.
METHODS
Controlled laboratory study using a cross-sectional design.


OBJECTIVE
To compare the measurements of navicular drop during walking and running to those made clinically during a static position in a group of healthy young adults.


BACKGROUND
The navicular drop test is a common clinical measure of foot structure and, more specifically, of talonavicular joint function. Previous work has focused on static measurement to establish the relationship between navicular drop and various overuse injuries. However, loads on foot structure are dramatically increased during gait. Examining navicular drop dynamically is more reflective of the functional demands of the foot when walking and running.


METHODS
The navicular drop of 72 healthy runners was evaluated using 2 static methods. Results were used to classify individuals into groups and compared to dynamic measures of navicular drop made during walking and running. Three-dimensional motion capture and an instrumented treadmill were used to assess dynamic navicular mobility. A repeated-measures analysis of variance (ANOVA) was performed to examine differences between measurement conditions. Between-group differences were assessed with independent-samples t test (P<.05).


RESULTS
Static measures of navicular drop were not found to be uniformly predictive of dynamic function during walking or running. Functional navicular drop measurements underestimated the dynamic measures in all foot types, while subtalar neutral drop overestimated dynamic measures for individuals with neutral and hypermobile foot types. No differences in navicular drop were found between foot types during walking, and small differences were found in running only between the hypomobile and hypermobile foot types. Maximum foot deformation during gait occurs at the time of maximum ground reaction force. Significant differences in navicular drop between foot type groups measured statically become muted when looking at group differences while walking and running.


CONCLUSIONS
Differences in navicular mobility between foot type groups during walking and running indicate that factors other than static alignment affect dynamic foot mobility. Dynamic assessment of navicular mobility may be an effective tool to examine the interplay of how the extrinsic force demands of gait and intrinsic structure and neuromuscular control affect foot function in walking and running.
Dicharry
Jay M
JM
Department of Physical Medicine and Rehabilitation, University of Virginia, Charlottesville, VA 22903, USA. JD4DA@virginia.edu
Franz
Jason R
JR
Della Croce
Ugo
U
Wilder
Robert P
RP
Riley
Patrick O
PO
Kerrigan
D Casey
DC
D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D012420:Running / Q000502:physiology; D013628:Talus / Q000502:physiology*; D013639:Tarsal Bones / Q000502:physiology*; D016138:Walking / Q000502:physiology