R code underlying the analysis reported in Predicting elbow load based on individualised (inter)segmental rotation in fastball pitching

The R code for external valgus torque prediction in baseball pitching. We fitted two-level varying-intercept, varying-slope Bayesian models with various combinations of observed kinematic predictors (pelvis peak angular velocity, trunk peak angular velocity and separation time). The weight and height of the pitchers were added to the kinematic predictors in all models to strengthen the individualization of the external valgus torque prediction. The purpose of the external valgus torque future prediction is to estimate elbow loading for every individual pitcher, not only ones included in this study. Therefore we used leave-one-group-out cross-validation to select the model with best predictive performance.