This is a construct of physical function that predicts falls and disability and is sensitive to change. The 30-second sit-to-stand test is administered using a folding chair without arms and involves recording the number of stands from a seated position a person can complete in 30 seconds. Change in 30-second sit-to-stand repetitions will be reported from baseline to Week 4 and from baseline to Week 8. An improvement in repetitions will represent an improvement in physical function. The continuous value correlates with quadriceps Minimal Clinically Important Difference (2.0 repetitions).

An objective measure related to upper extremity strength that predicts mobility disability. Using a Jamar dynamometer, change in participants' maximal grip strength will be measured in kilograms. Absolute change in grip strength will be reported from baseline to Week 4 and from baseline to Week 8. An increase in kilograms will represent an improvement in physical function. No cutoffs will be used, and analyses will use the continuous value.

PROMIS (Patient-Reported Outcomes Measurement Information System) Global Health gauges physical, mental, and social aspects of health using a standardized 5-point scale. Scores are standardized to the general population (mean = 50, SD = 10; range 0-100), with higher scores indicating better health. Change in PROMIS Global Health scores will be assessed from baseline to Week 4 and from baseline to Week 8.

PROMIS Physical Function is a self-reported measure of mobility and activities of daily living using a standardized 5-point scale. Scores are standardized to the general population (mean = 50, SD = 10; range 0-100), with higher scores indicating better physical function. Change in PROMIS Physical Function scores will be assessed from baseline to Week 4 and from baseline to Week 8.

The 15-item Pittsburgh Fatigability Scale measures perceived fatigue related to sedentary, social, lifestyle, and physical activities across a range of intensities (0-50 scale). Higher scores indicate greater perceived physical or mental fatigability, and scores ≥15 (physical) or ≥13 (mental) indicate higher fatigability that may lead to reduced performance or restricted activity. Change in Pittsburgh Fatigability scores will be assessed from baseline to Week 4 and from baseline to Week 8. A reduction in score will represent an improvement in fatigability.

The Self-Efficacy for Exercise Scale (range 0-90) is based on Social Cognitive Theory, with higher scores indicating greater confidence in initiating and maintaining exercise behaviors. Change in exercise self-efficacy scores will be assessed from baseline to Week 4 and from baseline to Week 8. Positive changes will reflect improved self-efficacy, while negative changes will reflect reduced self-efficacy.

A 10-item Likert scale (1-10) will be used to assess daily technology self-efficacy, with higher scores indicating greater self-efficacy (range 0-100). Change in Technology Self-Efficacy scores will be assessed from baseline to Week 4 and from baseline to Week 8.

A validated 15-item, 7-point scale (range 0-100) reflecting autonomous and controlled motivation for exercise. Change in Treatment Self-Regulation scores will be assessed from baseline to Week 4 and from baseline to Week 8, with higher scores indicating better outcomes.

The Patient Activation Measure assesses knowledge, skills, and confidence for managing one's health, providing insight into motivation, behaviors, attitudes, and outcomes (score range 0-100, with higher scores indicating greater activation). Change in Patient Activation Measure scores will be assessed from baseline to Week 4 and from baseline to Week 8.

The Older Americans Resources and Services (OARS) Functional Assessment is a self-reported measure of functional ability in activities of daily living (ADLs) and instrumental activities of daily living (IADLs). Scores are calculated according to standard OARS scoring procedures, with higher scores indicating greater functional independence (score ≥12 indicating no impairment). Change in OARS Functional Assessment scores will be assessed from baseline to Week 4 and from baseline to Week 8.

Outcome expectancies for exercise and technology use will be assessed using a self-reported questionnaire evaluating participants' beliefs about their ability to prevent or improve loss of strength, muscle mass, and overall health through physical activity and use of technology. Participants respond using a 4-point Likert scale ranging from strongly agree to strongly disagree, with higher agreement indicating more positive outcome expectancies. Change in outcome expectancy scores will be assessed from baseline to Week 4 and from baseline to Week 8.

System usability will be assessed using the System Usability Scale (SUS), a validated self-reported questionnaire that measures perceived usability of a system. The SUS consists of 10 items, each rated on a 5-point Likert scale ranging from strongly disagree to strongly agree. Item responses are scored and summed according to standard SUS scoring procedures to generate a total score ranging from 0 to 100, with higher scores indicating better perceived system usability. The outcome will be expressed as the change in SUS total score from 4 weeks to 8 weeks.

Learnability of the BandPass system will be assessed using a self-reported questionnaire evaluating ease of use, confidence, navigation, and ability to use the system seamlessly over time. Participants rate items related to the BandPass resistance exercise band, the BandPass app, and the combined system using 10-point Likert-type scales. Higher scores indicate greater perceived ease of learning and confidence in using the system. Change in learnability scores from 4 weeks to 8 weeks will be reported.

Technology acceptance and efficiency will be measured using a self-reported questionnaire evaluating confidence in independent device use, perceived usefulness, convenience, burden, satisfaction, and efficiency. Scores are generated using 10-point Likert-type scales and summarized according to standard scoring procedures, with higher scores indicating more positive perceptions of technology acceptance and efficiency. Change in efficiency and technology acceptance scores will be assessed from Week 4 to Week 8.

User experience of the BandPass system will be assessed using the User Experience Questionnaire (UEQ), a validated self-reported questionnaire that evaluates participants' perceptions of the system across multiple dimensions, including attractiveness, clarity, efficiency, dependability, stimulation, and novelty. The UEQ consists of paired contrasting attributes rated on a 7-point semantic differential scale ranging from 1 to 7, with higher scores indicating a more positive user experience. Scores will be calculated according to standard UEQ scoring procedures. Change in UEQ scores from 4 weeks to 8 weeks will be reported.

A single-item Likert scale (1-10) will be used to assess perceived usefulness, ease of use, effectiveness, reliability, and satisfaction with the BandPass system (range 0-100), with higher scores indicating better outcomes. Scores will be assessed at Week 4 and Week 8, and change in Telehealth Usability Survey scores between these timepoints will be reported.

Perceived usefulness, ease of use, ease of learning, and satisfaction with the BandPass system will be assessed using a self-reported questionnaire. The questionnaire includes items evaluating effectiveness, productivity, usefulness, efficiency, ease of use, flexibility, learnability, error recovery, and overall satisfaction with the system. Items are rated on a Likert-type scale ranging from strongly disagree to strongly agree. Higher scores indicate more positive perceptions of the system. Change in questionnaire scores from 4 weeks to 8 weeks will be reported.

Willingness to pay for the BandPass system will be assessed using a self-reported questionnaire evaluating participants' willingness to pay for the application and exercise device and their willingness to travel to an exercise center in lieu of using the system in a home setting. Participants select predefined cost ranges and travel time categories reflecting perceived value and acceptability of the system.