Assessments
RPE
Intervention acceptability was assessed by a theoretical framework of acceptability questionnaire on participant experiences of exercise snacking completed at the follow-up assessment only. The seven domains (Affective attitude; Burden; Ethicality; Intervention Coherence; Opportunity Cost; Perceived effectiveness; and Self-efficacy) of the TFA along with overall acceptability were measured using an 8-item questionnaire [During eligibility screening, baseline characteristics were collected (Table At baseline and follow-up assessments, participants completed questionnaires on their attitude towards the benefits of exercise using the Multidimensional Outcome Expectancy for Exercise Questionnaire [Alongside the SPPB, physical function was also assessed by a 60-second sit-to-stand test, in which participants were instructed to complete as many repetitions as possible in 60 s from a hard backed chair with seat height of 45 cm. Participants were permitted to use their arms for balance, but not to use their arms to propel or push themselves out of the chair. To avoid any self-pacing, participants were positioned out of view of a clock and the researcher did not count the repetitions out loud. A single attempt was permitted, and rating of perceived exertion (RPE [To characterise habitual physical activity and assess intervention adherence, a wearable physical activity monitor (ActivPAL4, PAL Technologies ltd, Glasgow, UK) was worn on the thigh for the seven consecutive days after the baseline assessment. The device was mounted under an adhesive waterproof dressing so it could be worn continuously, including during water-based activity. Participants were provided with a pre-paid and addressed envelope in which to return the device following seven days of wear.