Abstract: This disclosure relates to a sensor-based monitor for movements of workers. Multiple inertial sensors are attached to different body parts of the workers. A mobile device application receives the inertial movement data from the sensors and identify movement patterns by applying a trained machine learning model to the inertial movement data. The application then determine for each movement pattern an amount of time that movement pattern occurred and accessing a database to retrieve stored data on an association between the identified movement patterns and injuries. The application calculates a risk value indicative of a risk of injury of the worker as a result of performing the identified movement pattern for the determined amount of time and produces a report detailing the risk value for each of multiple risk categories.