The aim of this study is to investigate the feasibility of an intervention to reduce sedentary behaviour in older adults waiting for hip and knee replacements. The study will be a randomised controlled trial design, including 2:1 randomisation into an intervention and usual care group respectively. A target of n=45 patients ≥60 years will be recruited from Russells Hall Hospital, Dudley, UK, approximately 8-10 weeks before surgery, assisted by research nurses. The variable-length intervention, informed by Self-Determination Theory (SDT), will be composed of multiple behaviour change techniques, namely motivational interviewing, individualised feedback on sedentariness, goal-setting, environmental modification, self-monitoring, and social support. Assessments will occur at baseline, 1 week pre-surgery, and 6 weeks post-surgery. The primary outcome will be the feasibility of the trial, assessed quantitatively using study statistics, and with mixed-methods assessment of acceptability, practicality, adaption, satisfaction, and safety via questionnaires given to participants. Exploratory outcomes will include physical function, cardiometabolic biomarkers, measurement of SDT constructs, and both objective and subjective measurement daily activity and sedentariness. The study will last up to 18 weeks per participant.

The aim of this study is to investigate the feasibility of an intervention to reduce sedentary behaviour in n=45 older adults undergoing orthopaedic surgery, at Russells Hall Hospital, Dudley, Birmingham, UK. Recruitment will be via screening of surgery lists followed by direct contact with potentially eligible participants. The intervention is designed utilising Self Determination Theory. It is designed to have multiple components: incorporating individualised feedback on sitting time, education about sedentary behaviour, individualised goal-setting and environmental modification according to each participant's own behavioural patterns and capabilities, motivational interviewing, and biweekly phone calls.

Due to variation in surgery times, the intervention will be variable but can last up to 18 weeks. Each participant will undertake 3-5 visits depending on whether they are in the control group (n=3 visits) or intervention group (n=5 visits). The intervention group will undergo baseline assessments, two intervention meetings, pre-surgical assessments, and a 6-week post-surgical follow up. These visits will occur in different weeks for each participant due to the variability of surgery, however visit 2 will occur 1 week after visit 1. Visit 3 will occur shortly thereafter but may also be combined with visit 2. Visit 4 will occur the week prior to surgery, which is intended to be 6-10 weeks after baseline. Visit 5 occurs 6 weeks post-surgery, which should be 12-18 weeks post-baseline. The primary outcome measure will be feasibility, assessed quantitatively with study statistics. Secondary outcome will be mixed-methods assessment of feasibility via bespoke participant questionnaires. Exploratory outcomes will cover a number of mental and physical health variables, including blood measures to assess cardiometabolic biomarkers, as well as physical function using the short physical performance battery (SPPB). Surgical recovery will be assessed using the Oxford Hip/Knee score and the SPPB. The results of this feasibility study will serve to aid the design of a definitive trial of an intervention to reduce sedentary behaviour in this population.

Inclusion Criteria:

1. Men and women aged ≥60 years.
2. Listed for elective hip or knee surgery.
3. Capable of providing informed consent.
4. Regular access to a phone at pre-specified times.
5. Able to speak English.

Exclusion Criteria:

1. Neuromuscular impairments that preclude participating in physical activity, visual, hearing, or moderate/ severe cognitive impairments as indicated by the research nurse prior to recruitment.
2. Significant co-morbid disease that would pose a safety threat, affect blood measures significantly, or impair ability to participate such as coronary artery disease, severe hypertension, peripheral vascular disease, stroke, congestive heart failure, chronic obstructive pulmonary disease, insulin-dependent diabetes, psychiatric disease, renal disease, liver disease, or an active cancer other than skin cancer.
3. Working more than 2 days per week.
4. Unwillingness or inability to comply with the intervention.