Comparison of Supervised and Unsupervised Physical Activity Programs During a Weight Loss Intervention for Adults

Approximately 69% of the U.S. adult population is overweight, defined by a body mass index
(BMI) of ≥ 25.0 kg/m2, and 35% are obese (BMI ≥ 30.0 kg/m2), with the prevalence of
overweight and obesity rising drastically over the past several decades. Adults who are
overweight or obese are typically recommended to change lifestyle factors (e.g. diet,
physical activity, etc.) to lose weight and improve health. When evaluating the effects of
these lifestyle changes on weight and health in a research setting, physical activity is
supervised (i.e. physical activity completed in a health-fitness facility with direct
supervision from trained staff). With supervised physical activity, researchers are able to
quantify the frequency, intensity, duration, and type of physical activity. Thus, supervised
physical activity is considered the gold-standard when evaluating the effects of physical
activity on weight and other physiological parameters. However, the results of supervised
physical activity trials may not translate to clinical settings. A typical clinical approach
prescribes physical activity in an unsupervised manner (i.e. physician tells patient to be
more physically active or take more steps/day). Unsupervised physical activity can be done in
any environment or at any time that best suits the individual. Knowing the effects of
unsupervised physical activity is important because of the translation of this type of
physical activity to non-research settings. Therefore, knowing the magnitude of the
physiological effects of unsupervised physical activity compared to supervised physical
activity at the same prescribed intensity and dose is of clinical and public health
importance especially in an overweight and obese population. This study is designed to
provide insight on these important research questions that can inform future research and the
application to clinical, public health, and health-fitness settings.

Participants will be randomized to one of three groups: supervised physical activity
prescribed in min/week (SUP-PA), unsupervised physical activity prescribed in min/week
(UNSUP-PA), and unsupervised physical activity prescribed in steps/day (STEP). Participants
in all three groups will participate in a behavioral weight loss intervention which includes
dietary counseling and weekly group sessions during the 12-week program. SUP-PA will be
prescribed 150 minutes/week of moderate-to-vigorous physical activity (MVPA) completed under
direct supervision of trained staff at a designated health-fitness facility. UNSUP-PA will be
prescribed a physical activity dose matched to SUP-PA. STEP will be prescribed a 10,000
step/day recommendation with 2,500 of those steps completed at a "brisk" pace. The primary
aim of this study is to compare the effects of all three groups on moderate-to-vigorous
physical activity (MVPA) accumulated in bouts of at least 10 minutes. The primary outcome
will be assessed at baseline, week 4, week 8, and week 12. Secondary aims of this trial
include comparing light intensity physical activity, sedentary time, cardiorespiratory
fitness, weight, body composition, waist circumference measures, physical activity
self-efficacy, blood pressure, and dietary intake across all three groups. Secondary aims
will be assessed at baseline and week 12.

Inclusion Criteria:

- Male or Female

- Aged 18-55 years old

- BMI of 25.0 to <40.0 kg/m2

- Ability to provide informed consent

- Ability to provide physician's clearance to participate in a weight loss intervention

Exclusion Criteria:

- Engaging in >60 min/wk (accumulated in bouts of ≥10 minutes) of moderate-to-vigorous
physical activity over the past month

- Presence of contraindications to physical activity as identified on a physical
activity readiness questionnaire (PAR-Q)

- History of metabolic, cardiac, or pulmonary disease that classifies the individual as
high risk by the American College of Sports Medicine (e.g., coronary heart disease,
diabetes mellitus, uncontrolled hypertension, etc.)

- History of myocardial infarction, coronary bypass surgery, angioplasty, or other
cardiovascular- related surgeries.

- Taking medication that may affect heart rate or blood pressure responses to physical
activity

- Resting systolic blood pressure ≥150mmHg or diastolic blood pressure ≥100mmHg.

- Medication that may affect body weight/metabolism (e.g., synthroid).

- Current or previous participation in a physical activity or weight management research
project in the past 6 months

- Weight loss of ≥5% or 15 pounds total of current body weight in the previous 6 months.

- Currently being treated for an eating disorder (e.g., anorexia, bulimia, etc.)

- Previously undergone bariatric surgery (e.g., lap-band, gastric bypass, etc.)

- For women, those currently pregnant, pregnant during the previous 6 months, or plan on
becoming pregnant in the next 6 months

- Currently being treated for any psychological issues or problems, taking any
psychotropic medications, or receiving treatment with psychotropic medications within
the previous 6 months.

- Being out of town during for an extended amount of time during the weight loss
intervention which may affect participation in the study

- Currently using a physical activity monitor to track activity (e.g., Jawbone UP,
Fitbit, etc.)