OBJECTIVES/GOALS: Persons with Parkinson’s disease (PwPD) have set-shifting impairments that may limit motor learning of protective responses to prevent falls. This study compares the effect of blocked versus random practice schedules on acquisition and retention of protective stepping stability in PwPD & age-matched controls. METHODS/STUDY POPULATION: Twenty PwPD & 20 age-matched controls will be randomly assigned to random or blocked practice groups to experience slip and trip-like perturbations which induce stepping responses. Blocked practice is repeating a task (e.g., slip) several times before the next task, while random practice is randomly practicing two or more tasks (e.g., slips & trips). Each subject will wear a safety harness to prevent falls, each fitted with a load cell that indicates when a fall would have occurred. We will assess the anterior-posterior and mediolateral margin of stability at 1st protective step, step length, and in-task fall incidence before, 10 minutes, and two days after practice. We will also compare outcomes between participants in the blocked vs. random practice schedule using two ANOVA. RESULTS/ANTICIPATED RESULTS: To date, we have recruited three control subjects. We anticipate that blocked practice will be superior to random practice for protective stepping acquisition and retention PwPD. Existing literature on motor learning of voluntary tasks indicates that PwPD have difficulty acquiring and retaining motor skills via random practice due to the higher cognitive processing required than blocked practice. Furthermore, since the basal ganglia’s set-shifting role is crucial for random practice, it is expected that random practice will limit protective steps acquisition and retention in PwPD. In healthy control, while blocked practice is better for acquisition, random practice will be superior for retention. DISCUSSION/SIGNIFICANCE: The study’s findings will provide knowledge that may foster the development of robust balance rehabilitation protocols to improve postural responses in PwPD and reduce delayed and ineffective stepping responses that results in falls among PwPD.