Assessing the impact of walking with inflatable cuffs on fitness and function of older people

The intervention will be a 12-week supervised walking program for older adults (aged >60 yrs). The walking will be performed while wearing inflatable cuffs on the legs to cause moderate blood flow restriction (BFR). This will be a two-armed RCT. Older people will be recruited to undertake a 12-week walking exercise intervention. Participants will also be followed up at 6 and 12 months after the exercise intervention has concluded. Participants will be randomly allocated to one of two arms for the duration of the study: ARM 1 - Traditional walking (TW): Participants fill follow a walking program for 12 weeks. This will be supervised by an Exercise Scientist with >4 years experience in prescribing and implementing exercise programs, and will take place around the campus of Murdoch University (Perth, Australia). The walking will be performed 3 times per week for 50 minutes each session, and will be of a moderate intensity (approximately 3-6 km/hr), totalling 150 minutes of physical activity (i.e. following the standard guidelines for cardiovascular exercise from the American College of Sports Medicine). ARM 2 - Walking with blood flow restriction (BFRW): The exercise interventions in this group will be similar to ARM 1, in that participants will perform a 12-week supervised walking intervention at moderate speed. This walking exercise will be completed whilst wearing inflatable BFR cuffs on their upper thighs (inflated to sub-occlusive pressures) for portions of each exercise session. These cuffs are 10cm wide, and similar to a cuff that would be used to assess blood pressure with a GP. They simply wrap around the legs and velcro to themselves to stay in place. The cuffs are inflated with a rubber bulb and pressure gauge, that are then detached to ensure constant pressure during exercise (i.e. are not monitored for pressure changes during exercise). This group will perform 3 sessions per week of 25 minutes (total 75 minutes per week), with the BFR cuffs inflated for 20 minutes of the total 25 minutes. The actual pressure applied will be individualised for each participant as 60% of the pressure required to occlude blood flow at rest (i.e. the arterial occlusion pressure; AOP). The AOP will be determined individually for each participant in their initial training session via gradual cuff inflation whilst auscultating the posterior tibial artery with doppler ultrasound, to determine the pressure required for complete occlusion. Exercise adherence will be assessed for all participants in the research by an Exercise Scientist who is running the training sessions. The total number of sessions completed will be recorded to indicate adherence to the program and the training dose experienced.