Testing a Brief Motivational Intervention to Increase Physical Activity for Cancer Survivors

The primary outcomes will be measured with Fitbit data. Fitbit software allows classification of each minute as being in sedentary, light, moderate, or vigorous activity, and provides metabolic equivalents (METs) for each minute. Positive changes in levels of physical activity will be determined by a 25% increase in MVPA from baseline to end of intervention. This estimation is based on a systematic review of motivational physical activity interventions in cancer survivors (Takemura, 2024). This change in outcome measure is well justified and sensitive to small changes in activity.

SF-20 includes 20 quality-of-life statements that are well validated and reliable. The survey measures health across 6 domains: physical functioning (6 questions), role functioning (2 questions), social functioning (1 question), mental health (5 questions), health perceptions (5 questions), and pain (1 question). The total score will be used to measure quality of life and the physical functioning domain score will be used to subjectively measure physical functioning. Higher scores indicate better health.

Sleep will be measured with the PROMIS Sleep Disturbance short form, a 6-item scale that assesses sleep quality and satisfaction with sleep on a five-point Likert scale. The scale is reliable and valid and correlates strongly with longer forms. Higher scores indicate more sleep disturbance.

Fatigue will be measured with the PROMIS Fatigue short form. This scale includes 8 items related to fatigue and the impact of fatigue on day-to-day life. The form has good reliability (0.88) and validity (.60 -.85) across different groups and has been used across diverse clinical populations. Higher scores indicate more fatigue.

Physical function will be derived from performance on the Short Physical Performance Battery (SPPB). The SPPB consists of 3 components: balance (side-by-side, semi-tandem, and tandem positions held for 10 seconds unassisted), gait speed (amount of time to walk a four-meter course at a typical pace), and repetitive chair stand (amount of time to rise from a chair unassisted 5 consecutive times). Each component is rated on a 4-point scale based on the ability and amount of time necessary to complete each task. SPPB ≥10 indicated scores in the normal range, whereas a score of ≤9 indicated functional impairment (further stratified into mild (7-9) vs moderate (4-6) to severe (≤3)). Grip strength will be measured by using a standard dynamometer and assessed from a single 3-s maximal grip effort of the right- and left-side arms. Decreased grip strength has been strongly associated with a range of adverse health outcomes.

The PTSD Checklist for DSM-5 (PCL-5) is a 20-item self-report questionnaire that assesses Post-Traumatic Stress Disorder (PTSD) symptoms on a 5-point Likert scale, with total scores ranging from 0 to 80. Symptoms are grouped into four clusters corresponding to DSM-5 PTSD criteria, and scoring involves summing item responses to calculate a total score or to identify minimum symptom endorsement for a provisional diagnosis. Higher scores indicate more severe PTSD symptoms, with scores of 31-33 or above generally considered clinically significant and potentially indicative of PTSD