ML-assisted MBM performance after training on results from helmet impact tests. (a) Flow diagram for evaluating the ML model trained on helmet impact tests (MBM-ML-helmet), where i represents each planar direction. (b) MBM-ML-helmet model performance on the testing set of helmet impact acceleration inputs. (c) MBM-ML-helmet model performance on independent human impact reconstructions. The shaded region lies outside the lower bound MPS of the training set for the ML model, creating an MPS prediction floor. Error metrics only include points within the bounds of the training set.