Abstract: Systems and methods for assessing, monitoring, or theranosing a condition or disorder based on a comparison of limb stability for one or more limbs of a subject from a baseline. The method includes placing two or more inertial measurement sensors on the limbs of the subject, acquiring baseline limb excursion data from the inertial measurement sensors while a patient is performing at least one of a static balance activity and a dynamic balance activity by tracking the relative displacement of the respective two or more inertial measurement sensors; acquiring post-injury limb excursion data after an injury from the inertial measurement sensors while a patient is performing at least one of a static balance activity and a dynamic balance activity; and determining the activity clearance index as a function of a comparison of the baseline limb excursion data compared to the post-injury limb excursion data.