Background: Gait disturbance is one of the most common complaints from patients with Parkinson's disease (PD). It is well-established that due to the dysfunction of the corticostriatal circuits, people with PD have motor learning impairments and may consequently influence the effects of rehabilitation. To enhance motor learning, several methods have been recommended, such as sleep, non-invasive brain stimulation techniques, and aerobic exercise. To date, only 2 studies have investigated the effects of acute aerobic exercise on motor learning in people with PD. These 2 studies were cross-sectional studies that only provided a single bout of aerobic exercise and followed the effects on motor learning for 7 days. It is yet unclear whether adding aerobic exercise after goal-based motor skill training for multiple training sessions, like a regular clinical treatment regimen, can boost up the speed of motor skill acquisition and enhance retention and transfer performances for people with PD. Additionally, most prior evidences utilized moderate to high intensity aerobic exercise to facilitate motor learning, it is yet unclear whether other types of exercise (e.g., resistance training) could induce similar beneficial effects. To the best of our knowledge, no study is specifically designed to compare the addictive effect of aerobic or resistance exercise on motor skill learning in people with PD. Therefore, this proposed project is specifically designed to answer the above questions. To take a step further, this project will also determine the patient characteristics who may benefit from the intervention.

Objectives: (1) To examine whether adding aerobic or resistance exercise after walking skill training can facilitate learning of the walking task on patients with Parkinson's disease. (2) To determine the characteristics of participants who may benefit from these types of intervention approach.

The first aim of this study is to investigate investigate the effects of adding aerobic or resistance exercise after gait training in people with PD. The second aim is to further determine the characteristics of participants who benefit from the proposed training program..

Methods: A total of 76 participants with idiopathic PD diagnosed by neurologists will be recruited. All eligible participants will be randomized into one of the 4 groups: aerobic group (AEX), resistance group (REX), conventional PT group (CPT), and control group (CON). All participants will receive one-on-one intervention sessions with a trained physical therapist. Each intervention sessions will last 60 minutes, which will include 30 minutes of treadmill training and an additional therapy based on group allocation. The participants will come to the lab for 12 training sessions spread across 4 to 6 weeks. All outcome measures will be assessed before the intervention (pre-test), after the 6th intervention session (mid-test), after all 12 intervention sessions (post-test), and 1-month after the intervention (follow-up test). All assessments will be performed by an independent research assistant who will be blinded to the group allocation of the participants. The primary outcome will be gait performance, and the secondary outcomes will include Montreal Cognitive Assessment test, Stroop Color-Word test, Unified Parkinson's Disease Rating Scale, Fatigue Severity Scale, Activities-Specific Balance Confidence Scale, Parkinson's Disease Questionnaire-39, New Freezing of Gait Questionnaire, Geriatric Depression Scale, finger sequence task, Timed Up and Go test, 5 times sit to stand test. Transcranial magnetic stimulation will be used to examine the changes of corticomotor excitability associated with the interventions.