Methods, systems, and computer-readable media are provided for enabling improvements in athlete training and injury management through entropy and third-order spectral analysis of digitized force-vs-time time series from movements. In embodiments, entropy and/or bispectral statistics are determined using time-series information obtained from movements of an athlete, such as squat jump and countermovement jump maneuvers, using a biomechanical sensor, such as a digital force plate apparatus. These statistics may be used to facilitate sports medicine and health management of the athlete. In some embodiments, where athletes are involved in sport that involves explosive power development in the lower extremities and extensive running, cutting, jumping or other movement having risk of injuries to the lower extremities, time series force plate data are obtained and transformed to calculate entropy and bispectral statistics, from which functional status of the lower limbs and readiness for safe return-to-play may be ascertained.