Research participant receives the Core Intervention + E-Coach + General Mindfulness Training

Research participant receives the Core Intervention + E-Coach + MVPA Specific Mindfulness Training + Buddy

Research participant receives the Core Intervention + E-Coach + MVPA Specific Mindfulness Training

Research participant receives the Core Intervention + General Mindfulness Training + Buddy

Research participant receives the Core Intervention + General Mindfulness Training

Research participant receives the Core Intervention + MVPA Specific Mindfulness Training + Buddy

Research participant receives the Core Intervention + MVPA Specific Mindfulness Training

Research participant receives the Core Intervention + General Mindfulness Training + MVPA Specific Mindfulness Training + Buddy

Research participant receives the Core Intervention + General Mindfulness Training + MVPA Specific Mindfulness Training

Research participant receives the Core Intervention + Buddy

Research participant receives the Core Intervention

Participants assigned to this condition will receive a weekly scheduled text message from their coach. Text messages will focus on building self-efficacy and self-regulation skills, setting realistic outcome expectations, overcoming barriers, and problem-solving and will directly support the participant's engagement in the intervention. The coach will provide a brief overview of the participant's recent progress and goals, ask if they are having any barriers and help them troubleshoot and set specific goals for the next week. Text message protocols will be informed by the investigators' previous experience using telephone coaching to promote MVPA in cancer survivors. In addition to the scheduled messaging, participants will also be instructed to reach out to their coach with any questions or for additional assistance.

Participants assigned to this condition will be instructed to watch 1 (1-2 mins), mindfulness education videos each week which lay the foundation for what mindfulness is and how it can be an important health behavior. Each week participants will also be asked to listen to general guided mindfulness audio files ≥5 days/ week. The length of recordings will gradually increase each week from 3-5 to 25-30 minutes. All videos and recording will be available via the Opt2Move app.

Participants assigned to the MVPA-specific mindfulness training component will be instructed to watch 1-2 brief (1-2 minute), mindfulness education videos each week which lay the foundation for what mindfulness is and the importance of linking mindful awareness with MVPA. Each week participants will be provided access to MVPA-specific guided mindfulness audio files (e.g., 10-minute treadmill walking meditation, 20-minute bicycling meditation) that they will be asked to listen to during ≥3 MVPA sessions/week. The length and intensity of these audio files will correspond to their progression in the program. All videos and recordings will be accessed via the Opt2Move app.

Participants assigned to this condition will select a buddy of their choice (i.e. friend, co-worker, caregiver or family member) that is ≥ 18 years of age and willing to share their Fitbit data with the study team. The buddy will be mailed a Fitbit, share their Fitbit data with the study team, and be provided with access to, and instructions for, all of the Opt2Move app modules the participant has access to for their assigned condition. The Opt2Move app will include a buddy module where the buddy and participant can view each other's progress. The buddy will be expected to attend a 15-30 minute group orientation call and listen to four 10-15 minute podcasts (one every 3 weeks) during the first 12 weeks of the intervention. Each podcast will provide social support training and peer discussion of challenges and successes in providing YACS with MVPA support.

Symptom burden of anxiety will be measured at baseline and 12 and 24 weeks using the PROMIS 29 Profile v2.1.

This 4-item scale measures uses a 5-point Likert scale (1=never to 5=always). The minimum value one can score is 4, and the maximum is 20. The lower scores represent better outcome.

Symptom burden of depression will be measured at baseline and 12 and 24 weeks using the PROMIS 29 Profile v2.1.

This 4-item scale uses a 5-point Likert scale (1=never to 5=always). The minimum value one can score is 4, and the maximum is 20. The lower scores represent better outcome.

Symptom burden of fatigue will be measured at baseline and 12 and 24 weeks using the PROMIS 29 Profile v2.1.

This 4-item scale uses a 5-point Likert scale (1=not at all to 5=very much). The minimum value one can score is 4, and the maximum is 20. The lower scores represent better outcome.

Symptom burden of sleep disturbance will be measured at baseline and 12 and 24 weeks using the PROMIS 29 Profile v2.1.

This 4-item scale uses a 5-point Likert scale (1=not at all to 5=very much). The minimum value one can score is 4, and the maximum is 20. The lower scores represent better outcome.

Symptom burden of sleep disturbance will be measured at baseline and 12 and 24 weeks using the PROMIS Sleep-Related Impairment - Short Form 4a.

This 4-item scale uses a 5-point Likert scale (1=not at all to 5=very much). The minimum value one can score is 4, and the maximum is 20. The lower scores represent better outcome.

Ability to participate in social roles and activities will be measured at baseline and 12 and 24 weeks using the PROMIS 29 Profile v2.1.

This 4-item scale uses a 5-point Likert scale (5=never to 1=always). The minimum value one can score is 4, and the maximum is 20. The lower scores represent better outcome.

Symptom burden on applied cognitive abilities will be measured at baseline and 12 and 24 weeks using the PROMIS Applied Cognition-Abilities-Short Form 4a.

This 4-item scale uses a 5-point Likert scale (1=not at all to 5=very much). The minimum value one can score is 4, and the maximum is 20. The higher scores represent better outcome.

Pain interference will be measured at baseline and 12 and 24 weeks using the PROMIS 29 Profile v2.1.

This 4-item scale uses a 5-point Likert scale (5=never to 1=always). The minimum value one can score is 4, and the maximum is 20. The lower scores represent better outcome..

Pain intensity will be measured at baseline and 12 and 24 weeks using the PROMIS 29 Profile v2.1.

This 1-item scale uses a 11-point Likert scale (0=no pain to 10=worst pain imaginable). The minimum value one can score is 0, and the maximum is 10. The lower score represents better outcome..

Physical Self-Perception will be measured at baseline and 12 and 24 weeks using the Physical Self-Perception Profile-Physical Self-worth Subscale.

This instrument used to assess self-esteem relative to several domains of physical functioning in a hierarchical, multidimensional fashion. The instrument contains a general physical self-worth scale (PSW) which subsumes four more specific scales of perceived sport competence (SPORT), physical condition (COND), attractive body (BODY), and strength (STRENGTH), with six items per scale. Participants indicated on a four-point scale the degree to which each item is characteristic or true of them. Responses range from 1 (not at all true) to 4 (completely true), with higher scores representing better outcome. The minimum value one can score is 6, and the maximum is 24.

Confidence in ability to be regularly active will be measured at baseline and 12 and 24 weeks using the Exercise Self-Efficacy (EXSE).

This short form assesses the participants' beliefs in their ability to be regularly active "for the next 12 weeks" on a scale from 0% (not at all confident) to 100% (completely confident), with higher scores representing better outcome.

Confidence in ability to be regularly active despite common barriers will be measured at baseline and 12 and 24 weeks using the Barries Self-Efficacy (BARSE).

This scale assesses the beliefs in ability to be regularly active despite common barriers "for the next 12 weeks" on a scale from 0% (not at all confident) to 100% (completely confident), with higher scores representing better outcome.

Leisure time physical activity will be measured at baseline and 12 and 24 weeks using the Godin Leisure Time Exercise Questionnaire Physical Activity.

This is a measure of self-reported physical activity participation. Participants report "times per week" they participate in strenuous (e.g., jogging), moderate (e.g., fast walking), and mild (e.g., easy walking) exercise over the past 7 days and the "average duration each time you exercised (in minutes)" for each of the three activity categories. Weekly minutes of total, light, moderate, and vigorous activity are calculated by multiplying the frequency and time of each activity. This value is divided by 7 to obtain daily averages. The minimum value one can score is 0, and the maximum depends on the number of self-reported minutes of physical activity. Higher scores indicate better outcome.

Sitting time in young adult cancer survivors will be assessed at baseline and 12 and 24 weeks using the Sitting Time Questionnaire.

This questionnaire assesses the amount of hours and minutes spent sitting during weekdays and weekends, with lower scores representing better outcome.

Outcome expectations for exercise in young adult cancer survivors will be assessed at baseline and 12 and 24 weeks using the Outcome Expectations for Exercise_MOEES.

This scale assesses the beliefs and expectations about the benefits of regular exercise and physical activity on a scale from 1 (strongly disagree) to 5 (strongly agree), with higher scores representing better outcome.

Symptom burden on self-esteem will be measured at baseline and 12 and 24 weeks using the Rosenberg Self-Esteem Scale.

This scale assesses global self-esteem and consists of 10-items asking participants to indicate their level of agreement/disagreement with each statement. Sample items include: "I feel that I'm a person of worth, at least on an equal basis with others;" and "I am able to things as well as most people." Participants respond on a 5-point Likert scale ranging from 1 (strongly agree) to 5 (strongly disagree). The minimum value one can score is 10, and the maximum is 50. Higher scores indicate a better outcome.

Symptom burden on emotional support will be measured at baseline and 12 and 24 weeks using the PROMIS Emotional Support - Short Form 4a.

This 4-item scale uses a 5-point Likert scale (1=never to 5=always). The minimum value one can score is 4, and the maximum is 20. The higher scores represent better outcome.

Social support for exercise will be measured at baseline and 12 and 24 weeks using the Social Support for Exercise Scale.

This scale assesses support for physical activity received from the following categories: family, friends, and other cancer survivors. Statements are scored on a Likert scale of 1 (never) to 5 (very often) for each of the three categories, with higher scores representing better outcome. The minimum value one can score for each category is 10, and the maximum is 50. The minimum value of the total measure is 30, and the maximum is 150. An additional "does not apply" response option is provided on the measure.

Mindful awareness of distressing thoughts and images will be measured at baseline and 12 and 24 weeks using the Southampton Mindfulness Questionnaire (SMQ).

This 16-item scale measures mindful awareness during distressing thoughts and images. Using a 7-point Likert scale (0=strongly disagree to 6=strongly agree), items reflect the following subscales: mindful observation (4 items), letting go (4 items), non- aversion (4 items), and non-judgment (4 items). The minimum value one can score on any of the subscales is 0, and the maximum is 24. The minimum value of the total measure is 0, and the maximum is 96. The higher scores represent better outcome.

Mindful acceptance will be measured at baseline and 12 and 24 weeks using the Mindful Allowance - Acceptance v1.0 - Short Form 4a.

This 4-item scale measures uses a 5-point Likert scale (1=not at all to 5=very much). The minimum value one can score is 4, and the maximum is 20. The higher scores represent better outcome.

Mindful self-kindness will be measured at baseline and 12 and 24 weeks using the Mindful Allowance - Self-Kindness v1.0 - Short Form 4a.

This 4-item scale measures uses a 5-point Likert scale (1=not at all to 5=very much). The minimum value one can score is 4, and the maximum is 20. The higher scores represent better outcome.

Mindful de-centering will be measured at baseline and 12 and 24 weeks using the Mindful Insight - Decentering v1.0 - Short Form 4a.

This 4-item scale measures uses a 5-point Likert scale (1=not at all to 5=very much). The minimum value one can score is 4, and the maximum is 20. The higher scores represent better outcome.

Mindful presence will be measured at baseline and 12 and 24 weeks using the Mindful Presence - Awareness v1.0 - Short Form 4a,Mindful Presence - Curiosity v1.0 - Short Form 4a, and Mindful Presence v1.0 - Short Form 8a.

The measures use a 5-point Likert scale (1=not at all to 5=very much). The minimum value one can score on the 4-item scales is 4, and the maximum is 20. The minimum value one can score on the 8-item scales is 8, and the maximum is 40. The higher scores represent better outcome.

Meditation experience in young adult cancer survivors will be assessed using the Meditation Experience Questionnaire, a local questionnaire developed by the study researchers.

Participants will report on their experience and familiarity with meditation concepts and practices. The measure uses Yes-No response options (1=Yes; 0=No). The minimum value one can score is 0, and the maximum is 5. The higher scores represent better outcome.

Meditation practice in young adult cancer survivors will be assessed using the Meditation Experience Questionnaire, a local questionnaire developed by the study researchers.

Participants will report on meditation practice. How long participants have practiced meditation is measured on a 4-point Likert scale (1="not applicable, I don't practice" to 4="5 or more years"). Average weekly practice frequency is measured on a 7-point Likert scale (1="Not applicable, I do not meditate on a regular basis" to 7="More than once a day"). Average time spent on meditation sessions is measured on a 6-point Likert scale (1="Not applicable, I do not meditate on a regular basis" to 6="Greater than 60 minutes").The minimum value one can score on is 1; the maximum is 17. Higher scores represent better outcome. Significant change will be indicated by p<.05 on reported practice between baseline and follow up time points between interventions.

This indicator of implementation feasibility for the interventions delivered is defined by the overall enrollment rate being >/= 70% (e.g., total number of individuals enrolled/total number approached). Enrollment rate will be tracked continuously during the 24 week study.

This indicator of implementation feasibility for the interventions delivered is defined by the retention rate being >/= 70% (e.g., total number of participants who drop out/ total number randomized). Retention rate will be tracked continuously during the 24 weeks of the study and significant differences between the study interventions in the number of participant withdrawals will be tracked.

Adherence to the OPT2MOVE app + Fitbit will be monitored and usage tracked continuously during the 24 week study.

Objective data include Fitbit wear time, number of times app is opened each week, time spent in app each time it is opened, and for participants who receive each component, usage of general and moderate to vigorous intensity physical activity specific mindfulness videos (i.e. whether clicked, how many times and for how long), number of e-coaching exchanges, number of buddy training webinars attended, and number of buddy interactions in the app.

Acceptability will be measured using a brief, Likert-type survey assessing participant enjoyment, satisfaction, perceived benefit, and ease of use. Acceptability is defined as >/= 70% of survey responses in affirmation of this.

Change in body mass index in young adult cancer survivors will be assessed at baseline and 12 and 24 weeks using the Health History Questionnaire, a local questionnaire developed by the study researchers.

Participants will report on the following: height and most recent weight. BMI will be calculated. Significant change will be indicated by p<.05 on reported health behaviors between baseline and follow up time points between study interventions.

Change in health behaviors in young adult cancer survivors will be assessed at baseline and 12 and 24 weeks using the Health History Questionnaire, a local questionnaire developed by the study researchers.

Participants will report on the following: weekly leisure-time physical activities; weekly consumption of fruits, vegetables, red meat, processed meat, brown rice, beans, whole grain bread, fast food/snacks, caffeine, carbonated beverages; cigarette and alcohol use. Unhealthy behaviors will be reverse scored. Higher scores represent better outcome. Significant change will be indicated by p<.05 on reported health behaviors between baseline and follow up time points between study interventions.

Change in treatment expectations in young adult cancer survivors will be assessed at baseline and 12 and 24 weeks using the HEAL - Treatment Expectancy - Short Form, OPT2MOVE Expectancy Items, and Positive Outlook v1.0 - Short Form 6a.

Participants will report on the expectations they have about the outcomes of the study treatment. Each scale measure uses a 5-point Likert scale (1=not at all to 5=very much). The higher scores represent better outcome.

Change in life event related stress will be assessed at baseline and 12 and 24 weeks using the Health History Questionnaire, a local questionnaire developed by the study researchers.

This 10-item scale measures distress about life events (e.g., death of someone close; concerns about finances) on a 5-point Likert scale (0=not at all to 4=very much). The minimum value one can score is 0, and the maximum is 40. The higher scores represent better outcome.

environmental factors in physical activity participation will be measured at baseline and 12 and 24 weeks using the Physical Activity Neighborhood Environment Survey.

This 17-item questionnaire assesses environmental factors in physical activity participation, such as neighborhood safety, aesthetic qualities, neighborhood infrastructure, and access to destinations. Each question is rated on a 4-point Likert scale from 1 (Strongly disagree) to 4 (Strongly agree). Higher scores indicate higher neighborhood walkability.

Change in key components of M-PAC framework will be measured at baseline and 12 and 24 weeks using the Multi-Process Action Control (M-PAC) questionnaire.

The following components will be measured in 5-point Likert scale: affective attitude (score:3-15), instrumental attitude(score:3-15), perceived capability (score:3-15), perceived opportunity (score:3-15), behavioral regulation (score:6-30), habit formation (score:4-20), identity formation (score:4-20); and two items for decisional intentions (score:1-12). Higher score means higher levels of reflective, regulatory, and reflexive processes that may have facilitated exercise behavior change.

Change in executive function will be measured at baseline and 12 and 24 weeks using the Amsterdam Executive Functioning Inventory.

The 13-item inventory groups items into three dimensions: attention; self-control; and planning. Responses are scored on a 3-point Likert scale: from 1 (not true) to 3=(true). Total score of all items is calculated so that higher scores are indicative of better outcome.