SPRINT HEART: Study of Progressive Resistance and INterval Training in HEART disease

Eligible and consenting patients will be allocated to one of three study arms; high-intensity progressive-resistance training (PRT), high-intensity aerobic interval training (HIT) or standard medical care (SMC, control). The intervention period is 12 weeks in duration and training will be 3 times per week for approximately 60 minutes at the Faculty of Health Sciences Cumberland campus (Lidcombe). Training will be supervised by a postgraduate exercise physiology student, and initial sessions will also be supervised by the study physician. Session adherence and compliance to the exercise prescription will also be monitored and recorded by the postgraduate exercise physiology student. Participants will be contacted following any missed sessions, to encourage their attendance at subsequent training sessions. Progressive-resistance training: Week 1 of the intervention will include familiarisation and gradual increase in target intensity from 50, 60, 70% 1RM in each successive session. From the first session of week 2, training intensity will be set at 80% 1RM and progressed by a projected gain in strength of 3% 1RM each session, used in conjuction with Borg RPE Scale to maintain intensity at 80% 1RM. At the start of every 7th session, 1RM will be re-tested and target weight at 80% 1RM will be recalculated based on the new 1RM. Total training volume is 24 repetitions per exercise, set initially at 3 sets of 8 repetitions. However, as intensity is most important, sets and repetitions may be manipulated such that prescribed intensity is adhered to and the total volume remains 24 repetitions per exercise. Seven pneumatic resistance machines will be used and exercises will be completed in the following order; leg press, seated row, knee extension, chest press, knee flexion, tricep pushdown, hip abduction. Participants will be instructed to contract concentrically ‘as fast as possible’ and then 3-4 seconds of control through the eccentric phase. There will be 20-30 seconds of rest between repetitions and 3-5 minutes rest between sets to allow sufficient recovery of anaerobic metabolism. Aerobic interval training: Interval training will employ the 4x4 method, as used previously in cardiac populations (Moholdt et al. 2009). The protocol consists of 8 minutes of warm up working up to 70% peak heart rate (HRpeak), followed by four 4-minute intervals at a target of 85-95% HRpeak, each separated by 3 minutes of active recovery at ~70% HRpeak. During each of the 4-minute intervals, participants will progress from 70-80% HRpeak over the first 2-minutes, to that target intensity of 85-95% HRpeak for the final 2-minutes of each interval. Following the last interval, the participant will cool down to a slow walk with no gradient for a minimum of 5 minutes, or until breathlessness has ceased. Week 1 will serve as a familiarisation period, where the time spend at the target intensity will be increased from 30, 60, 90sec. Training will take place on a treadmill, at a self-selected brisk walking or running speed, with incline adjusted for intensity. Heart rate and oxygen saturation will be continuously monitored throughout each session and rate of perceived exertion [RPE] will be recorded in the last 15 seconds of every minute of training.