The central goal of the proposed study is to generate essential pilot data necessary to support an established line of research leading to future extramural grant submissions. The aims of the current study are two-fold: 1) to compare cardiorespiratory fitness (CRF) and gait endurance across three groups of people: (1) individuals with Parkinson Disease (PD) who participate in boxing on a regular basis, (2) individuals with PD who participate in exercise other than boxing on a regular basis and (3) healthy controls of the same age who exercise on a regular basis and 2) to examine the relationship between CRF and motor symptoms of PD (bradykinesia, tremor and postural instability). Forty-five participants (15 for each group) who participate in exercise on a regular basis (at least 120 minutes of exercise per week for the past 3 months) will be recruited for this cross-sectional study. In a single testing session, participants will perform the following tests: (1) clinical performance measures and (2) a CRF assessment. A one-way ANOVA with appropriate post hoc tests will be used to examine differences in dependent variables across the three exercise groups. Relationships between CRF and clinical performance measures will be evaluated with Pearson's correlation coefficients.

Inclusion Criteria:

• All participants included in this study must be between the ages of 55 and 75
• Be able to ambulate independently without physical assistance, assistive device, or lower extremity orthosis
• Be able to follow at least 3-step verbal commands
• Participate in a community-based group exercise program
• Be classified as regular exercisers by participating in 120 minutes per week for at least 3 months
• And have a physician's consent to undergo a graded exercise test (GXT).
• Furthermore, only participants that are identified as low or moderate risk for cardiovascular disease based on ACSM's risk stratification guidelines will be included in the study.
• Participants for the two PD groups must have a diagnosis of idiopathic PD
• Have a Hoehn-Yahr score of 1, 2, or 3
• And either participate regularly in boxing training at Rock Steady Boxing or participate in another community-based group exercise program on a regular basis, classified as 120 minutes per week for at least 3 months.

Exclusion Criteria:

• Participants may not be included in the study if they have had any surgery in the past 6 months
• Current musculoskeletal or complications from other health issues that influence walking.
• The participants without disability cannot be involved in the study if they have any preexisting neurological conditions.
• Participants with PD cannot be involved in the study if they have preexisting neurological conditions other than idiopathic PD (e.g. no diagnosis of Parkinson Plus syndrome), past brain surgery or implantation of a deep brain stimulator.

A total of 45 individuals will be enrolled in this cross-sectional study. Three groups will each consist of 15 individuals (individuals with Parkinson Disease that participate in boxing, individuals with Parkinson disease that participate in group exercise other than boxing, and individuals without disability that participate in group exercise other than boxing).