Usual care group
The usual care group (n = 50) will receive the usual care offered to participants who complete the 12-week Strength2Strength program. Follow up surveys are sent to participants at 3, 6 and 12 months’ post program to determine their current level of self-reported physical activity and sitting time (Fig. 2). Participants are also asked if they feel their activity levels have increased, decreased or stayed the same, reasons for a decrease in activity levels and how confident and motivated they are to continue to be physically active. Participants will attend assessments at 3, 6 and 12 months’ post program completion for collection of physiological variables, functional testing, physical activity and quality of life questionnaires, and health services usage data.
Remote physical activity monitoring
Participants randomised to the remote physical activity monitoring group (n = 50) will receive a Jawbone activity tracker at the end of the 12 week S2S program. They will be requested to wear the Jawbone on their wrist, or ankle if the wrist is not a suitable option, for the duration of the 12 month follow up period. The activity tracker will be set up to provide feedback, via vibrotactile alert, to participants on their compliance to their individual prescribed activity levels (50 & 100% of prescribed daily activity). These levels will be prescribed by the exercise physiologists as part of the S2S program. In addition to the feedback achieved while wearing the device, participants will be requested to synchronise their Jawbone device to the study database at the end of each day using a mobile internet link they will be provided with as part of the study. The daily synchronisation will also serve to recharge the Jawbone device for the following day’s use. In the event that a participant fails to synchronise the device at the end of the day they will be sent an automated text message reminding them of the need to recharge their device regularly and the synchronisation and recharge will occur when they next connect. As part of the daily synchronisation participants will receive further feedback regarding their overall progress during the intervention. This will include feedback regarding progress towards daily and weekly physical activity targets, general health tips and remote feedback from the Exercise Physiologists regarding ongoing compliance to the individualised exercise program. Participants will attend assessments at 3, 6 and 12 months post program completion for collection of physiological variables, functional testing, physical activity and quality of life questionnaires, and health services usage data.
Telephone counselling
Following the completion of the 12-week Strength2Strength program, participants (n = 50) will receive a follow up phone call once a fortnight for the first 3 months of the follow up period, and once a month for the remaining 9 months of the follow up period from the Exercise Physiologists. Participants will be asked to self-report on how they feel they are going with their activity levels and compliance to the home based program and if there are any issues that they feel are preventing them from being more physically active (Fig. 3). Participants will be provided assistance for any specific issues reported. Participants will attend assessments at 3, 6 and 12 months post program completion for collection of physiological variables, functional testing, physical activity and quality of life questionnaires, and health services usage data.
Outcome measures
Outcome data pertaining to physical function, quality of life, physical activity levels, and markers of clinical prognosis (BMI, waist circumference, brachial blood pressure) will be collected at the start and end of the 12 week S2S program and again at 3, 6 and 12 months of follow up after the participants have been randomised to one of the 3 interventions. All outcome measures will be collected for all three treatment groups at all time-points.
Physical activity measurement
Physical activity will be measured using two tools (a physical activity tracker and a questionnaire). Physical activity will be measured for a period of seven days at each time point through the use of ActivPal activity trackers. These will be fitted and worn day and night for the entire seven-day period with a minimum of five days’ worth of valid data required for inclusion at each assessment time. These trackers are reliable and valid [16, 17] for physical activity monitoring. Data obtained from the ActivPal activity trackers will be the primary measure of physical activity and expected changes to data obtained from these trackers form the basis of the sample size calculation for this study.
The physical activity questionnaire that will be used is the Active Australia questionnaire [18]. It will be included as a back-up activity monitor and to assess changes in time spent in different types of activities. Participants will be requested to include any exercise performed in the previous week in their response to the questionnaire. The survey measures frequency, intensity and duration of incidental and/or intentional physical activity in the week prior to the time of testing. The total time spent in each activity will be multiplied by an intensity value and used to calculate participants’ weekly physical activity in MET.min−1. This survey is valid and reliable [19, 20] and has previously been used to measure changes in physical activity in chronic disease populations [21].
Motivation for exercise
The self-regulation Questionnaire for exercise (SRQ-E) is a theoretically derived questionnaire developed for use in school settings but which has since been validated in diverse health settings [22]. The SRQ-E gathers information on why a person chooses to exercise regularly and assesses the degree to which individuals are autonomous in exercise behaviour.
Self-reported physical function (quality of life)
Self-perceived physical function will be evaluated using the Medical Outcomes Short-Form 36-Item Health Survey (SF-36). This survey includes 8 independent scales and assesses physical and mental dimensions of health. It is validated and has been widely used to measure quality of life in a range of chronic disease populations [21, 23, 24].
Physical function
The six-minute walk test (6MWT) or Modified Shuttle Walk Test (MSWT) will be used as the measure of physical function. Both tests require minimal equipment and are quick and easy to conduct. The 6MWT requires participants to walk as far as possible along a short measured course during the six minutes. They will be permitted to stop and rest if needed and will receive regular encouragement throughout the test. The MSWT is an incremental walk test requiring participants to walk along a short measured course while keeping pace with a recording. Both the 6MWT [25] and MSWT [26] are reliable and valid measures of physical function in patients with metabolic disease.
Muscle strength
Strength will be measured using the ten times sit to stand (TTSTS). TTSTS is a functional lower body strength measure that relates to ability to perform activities of daily living and consequently is relevant to wider health and quality of life outcomes. It is a reliable and valid measure that is widely used in clinical practice [27].
Dynamic balance and mobility
Dynamic balance and mobility will be measured using the timed up and go (TUG). This test involves the client standing up from an armless chair and walking around a cone placed 2.44 m in front of the chair, returning to the chair and sitting down. It is a reliable and valid measure of dynamic balance and is widely used in clinical practice [28].
Body composition
Three indicators of body composition will be measured. These are body mass index, waist circumference and percent body fat. These measures are simple and easy to attain and have been widely used as indicators of cardiovascular disease (CVD) [29] and mortality [30] risk in large scale population studies. Body Mass Index (BMI) will be calculated from height and body weight. Waist circumference will be measured at the narrowest point between the base of the rib cage and the iliac crest as per standard methods. Body fat percent will be assessed through the use of Bio-Impedance Analysis scales (Tanita BC-1000; Tanita Corp; Tokyo, Japan). BIA has previously been shown to be a reliable and reproducible method for determining body composition [31, 32].
Blood pressure
Brachial blood pressure will be measured by sphygmomanometry using standardised techniques after five minutes of seated rest.
Health Service Usage
Retrospective (covering before and during the study) information about medications (Medical Benefits Scheme (MBS) and Pharmaceutical Benefits Scheme (PBS) items of service from the Australian Department of Human Services, hospitalisations (Department of Health and Human Services Clinical Costing Dataset [electronic inpatient separation summary] for costing’s and morbidity) and mortality (AIHW National Death Register) will be collected. Out-of-pocket expenses, incidental and non-billable health professional encounters, and work missed through ill health will be assessed by health diaries to be maintained by each patient over the intervention and follow up periods (Fig. 4).
Adherence to the intervention
Participant adherence to the treatment interventions will be assessed through records of the proportion of intervention days that participants randomised to the remote physical activity monitoring group wear their activity monitor. Records will also be kept and reported regarding the the proportion of telephone calls successfully delivered to participants in the telephone counselling group as well as the length and content of these calls.
Sample size calculation
The 12 week S2S intervention resulted in a mean increase of 450 MET.min of physical activity per week with a SD of 1.5x the change. Sample size was calculated based on a predicted maintenance of 100% of additional physical activity in the feedback groups and decrease of 50% of additional physical activity in the usual care group over the 12-month intervention (Mean Difference = 225 Met.min/week) with a SD of the change of 350 MET.min/week (1.5x the mean change in line with S2S data). STATA 12 (Statistical data analysis; Stata Corp; College Station; Texas, USA) was used to calculate the sample size on the basis of a mean difference of 225 MET.min/week with a SD of the change of 350 MET.min/week, a power of 80% and an alpha level of 0.05 using the “sampsi 0 225, sd (350) p (0.8) a (0.05)” command. The sample size calculation indicated that at least 38 participants were required per group. To allow for potential withdrawals 50 participants per group will be recruited.