This study is a two-arm trial, comparing the effects of a virtual 12-week group-based exercise intervention vs. control group on physical activity, physical fitness, and quality of life in colorectal cancer survivors, and explore multi-level determinants of physical activity maintenance, 6-months after intervention completion.

Participants will be prospectively assigned or allocated to either a the exercise intervention or a control group for 12-weeks. The control group will be provided with an informational handout from the American Cancer Society describing exercise recommendations and guidelines for cancer survivors. At the end of the study, control group participants will be offered compensation for participation in a community-based cancer specific exercise program (e.g., BfitBwell, Fit Cancer, Livestrong at the YMCA). Supervised exercise sessions will take place twice per week for approximately one hour, and include aerobic, muscular strength and endurance, balance, and flexibility components. Sessions will be delivered synchronously (i.e., in real-time/live) via Zoom. Exercise will be individualized based on the results of baseline fitness assessments and medical history. The intervention will also include virtual, group-based discussion sessions which operationalize behavior change techniques to increase physical activity. Discussion sessions will take place in the same groups, synchronously, via Zoom.

Inclusion Criteria:

1. Provision to sign and date the consent form
2. Fluent in English
3. Have access to a computer or phone with internet and a camera
4. Stated willingness to comply with all study procedures and be available for the duration of the study
5. Be a male or female aged 40 years or older at time of diagnosis
6. Histologically confirmed cancer of the colon or rectum (stages II-IV) if treated with curative intent, and no current evidence of metastatic disease
7. Completed resection or other surgery 3-24 months prior to enrollment
8. Received chemotherapy and/or radiation therapy within the previous year, with at least 1 cycle of intended chemotherapy completed (does not need to complete all cycles). No plans for additional chemotherapy or radiation therapy.

Exclusion Criteria:

1. Current evidence of metastatic disease
2. Existing participation in ≥150 minutes per week of at least moderate intensity PA
3. Known contraindications for exercise or not able to safely participate in exercise
4. Pregnant women (no testing required)

PI and study staff conducting assessments at study visits will be blinded to study arm assignment.