Most people (~80%), if not all, persons with PD (PwPD) will experience freezing of gait (FOG) as the disease progresses into advanced stages. However, 21% to 27% of PwPD report FOG even in the early stages. This presentation will define the terminology and complex phenomenology underlying FOG. Participants will appreciate how this greatly interferes with research studies trying to clearly identify freezers from non-freezers so that we can better understand the data, the underlying mechanisms and the response to therapeutic interventions. Participants will be introduced to screening tools and assessments that can be used for early identification or for therapy outcomes after FOG-focused interventions. We will review 5 theoretical hypotheses (models) to help understand the pathophysiology underlying FOG. These will include the categories of: Interference, Threshold, Decoupling, Cognitive or Sensori-perceptual. For each model, we will first discuss examples of behaviors that we may be able to observe or elicit in the clinic that support different models and how that can provide insight for designing interventions. As we go through the models, we will introduce current research supporting interventions that may address one or more of these models. Emphasis will be on a recent meta-analysis that suggests that rehabilitation that targets multiple behavioral training modes related to 1) reducing the frequency or emergence of FOG episodes (proactive goals) and 2) circumventing and alleviating imminent FOG episodes (rescue goals) are efficacious. Altogether, these studies support the importance of starting early, incorporating cognitive strategies, challenging the intensity and complexity of training, targeting aerobic exercise to enhance neuroplasticity and addressing the unique challenges of sustained practice. The severity of functional mobility impairment in PwP is affected by dopamine-dependent disturbances that alter cortico-striatal networks and interfere with the ability to express habitual-automatic actions in complex real-world scenarios. Therefore, each of the proposed mechanisms that underlie FOG; may also contribute to the loss of automaticity and the deterioration of functional mobility. In addition, freezing and festination can occur in non-gait functions that require repetition and/or coordination across limbs or multiple structures like speech, repetitive finger or hand movements, bilateral reach and grasp movements, and during upper or lower limb floor crawling movements. For that reason, we propose that FOG interventions should consider the impact FOG has on ALL aspects of functional mobility. We will use Video case studies (n=2) to illustrate how FOG-specific interventions can be integrated within the PWR!Moves® Retrain Functional Mobility Framework allowing therapists to address personalized goals related to FOG but also everyday mobility and transfers in multiple positions or environments (home, work, recreation, community group exercise). Assessments used in the case studies, role of instruction, sensory feedback, use of simple multipurpose equipment and dosage consideration will be highlighted as part of case study discussion.