Medial longitudinal arch mechanics before and after a 45-minute run

Medial longitudinal arch integrity after prolonged running has yet to be well documented. We sought to quantify changes in medial longitudinal arch kinematics before and after a 45-min run in healthy recreational runners.

Thirty runners performed barefoot seated, standing, and running trials before and after a 45-min shod treadmill run. Navicular displacement, arch lengthening, and the arch height index were used to quantify arch deformation, and the arch rigidity index was used to quantify arch stiffness.

There were no statistically significant differences in mean (95% confidence interval) values for navicular displacement (5.6 mm [4.7-6.4 mm]), arch lengthening (3.2 mm [2.6-3.9 mm]), change in arch height index (0.015 [0.012-0.018]), or arch rigidity index (0.95 [0.94-0.96]) after the 45-min run (all multivariate analyses of variance P ≥ .065).

Because there were no statistically significant changes in arch deformation or rigidity, the structures of a healthy, intact medial longitudinal arch are capable of either adapting to cyclical loading or withstanding a 45-min run without compromise.