The primary aim of this study is to develop a feasible, acceptable, and effective multilevel physical activity (PA) intervention that addresses both individual and interpersonal factors that can be easily scalable and delivered in the context of a methadone clinic. To do so, the investigators will train methadone maintenance treatment (MMT) patients who are already engaging in PA at public health recommended levels to deliver a group-based PA intervention to physically inactive MMT patients at a large community-based methadone clinic. Through the development of interpersonal relationships and social support, the investigators expect that MMT peers who have successfully navigated challenges associated with PA in this population (i.e. depression, smoking, triggers for drug use in environment) will help physically inactive MMT patients increase self-efficacy and motivation for initiating and sustaining PA.

Opioid Use Disorders (OUDs) are a highly prevalent and costly public health concern in the United States, with over 2.59 million Americans qualifying for abuse or dependence of opioids in 2015. Methadone maintenance treatment (MMT), involving daily distribution of methadone at regulated clinics, is the most common treatment for opioid use disorder. While MMT has been effective in helping OUD patients improve their quality of life, the overwhelming majority of these patients continue to engage in unhealthy lifestyles (e.g., physical inactivity and cigarette smoking) that lead to significant physical and mental health morbidities. For example, patients in MMT have much higher rates of cardiovascular disease, diabetes, hypertension, obesity, depression, sleep difficulties, and cognitive impairments than age-matched controls, which lead to premature death. Given the mental health, physical health, and drug use related benefits of physical activity (PA), interventions targeting increases in PA in patients receiving MMT could have a significant impact on reducing their overall morbidity and mortality.

To date, few PA studies have been conducted with substance abusing populations - and, only one small pilot study with MMT patients. The goal of this project is to develop a feasible, acceptable and effective multilevel PA intervention that addresses both individual and interpersonal factors that can be easily scalable and delivered in the context of a health care setting (i.e., methadone clinics). To do so, the investigators are proposing to train MMT patients who are already engaging in PA at public health recommended levels to deliver a group-based PA intervention to physically inactive MMT patients at SSTAR Lifeline, a large community-based methadone clinic in Fall River, Massachusetts. Peer-facilitated interventions for self-management skills are common in the care of patients with chronic medical conditions. Peers may play a particularly important role in increasing physical activity in MMT, as this population faces unique and significant barriers to PA (e.g., depression, smoking, minimal social supports). Through the development of interpersonal relationships, the investigators expect that MMT peers who have successfully navigated these challenges will help physically inactive MMT patients increase self-efficacy and motivation for initiating and sustaining PA.

The aims of the study include:

1. PHASE 1 (Peer-PA Manual Development):

   • To develop a theoretically-informed peer-facilitated PA plus Fitbit (Peer-PA+Fitbit) intervention specific to SSTAR Lifeline, in order to help patients in MMT increase levels of physical activity.

     1. Focus groups will be conducted with: 1) MMT patients who are currently physically active and 2) MMT patients who are NOT meeting recommended PA levels to help inform intervention development.
     2. The investigators will: (1) develop a manualized Peer-PA intervention (that includes the use of a Fitbit activity monitor for self-monitoring PA and additional social networking), (2) create a training protocol for MMT patients to become peer-facilitators, and (3) identify safe, walkable paths in participant neighborhoods.

2. PHASE 2 (Open Pilot):

   • An open pilot trial will be conducted with 20 MMT patients to determine the feasibility, acceptability, and short term increases in PA of the Peer-PA+Fitbit intervention. At the end of 3 months:

     1. Feedback will be obtained on Peer-PA+Fitbit from both the MMT peers and participants through self-report measures and qualitative interviews.
     2. Adherence to the intervention will be determined through group attendance and Fitbit data.
     3. Short-term increases in physical activity levels will be examined through objectively measured PA.

3. PHASE 3 (Randomized Clinical Trial; RCT)

To conduct a 3-arm preliminary RCT of Peer-PA+Fitbit compared to Fitbit Only and compared to Usual Care (UC) among 150 MMT patients. We hypothesize that, Peer-PA+Fitbit will be superior to Fitbit Only and that Fitbit Only will be superior to UC on the following:

1. Higher levels of short-term (3-month) and long-term (6- and 12-month) objectively-measured steps/day and moderate-to-vigorous physical activity (MVPA)
2. Fewer days of drug use and lower levels of depression and anxiety symptoms at each follow-up
3. Higher levels of theoretically-relevant, PA-related variables including: self-efficacy, internal motivation, and social support at 3- and 6-month follow-ups

Inclusion Criteria:

• receiving MMT at SSTAR and planning to remain in treatment for the next 6 months
• low active (i.e., less than 90 minutes of MIPA per week for the past 6 months)
• has access to a computer connected to the internet or a smartphone compatible with the Fitbit application

Exclusion Criteria:

• a history of psychotic disorder or current psychotic symptoms
• current suicidality or homicidality
• marked organic impairment according to responses to the diagnostic assessments
• physical or medical problems that would not allow safe participation in a program of moderate intensity physical activity (i.e., not medically cleared by methadone clinic physician)
• current pregnancy or intent to become pregnant during the next 12 weeks