In one embodiment, a method includes accessing an athletic-performance model of a first user, where the model is based on a plurality of sets of action-parameter values of action parameters of the first user. The action-parameter values may be determined based on biomechanical data of the first user performing a plurality of actions of a first action-type and outcome data of each action. A current skill level of the first user may be determined based on a measure of variances associated with action parameters of the first action-type. Target ranges of action-parameter values may be calculated for action parameters based on the athletic-performance model. Each target range may be based on a measure of probability with respect to the particular action parameters and the outcome data. A report of athletic-performance feedback may be generated and may include current skill level information and the target ranges of action-parameter values.