Can mixed circuit training elicit the recommended exercise intensity and energy expenditure in people after stroke?

Purpose: To investigate whether mixed circuit training (MCT) elicits the recommended exercise intensity and energy expenditure in people after stroke, and to establish the between-day reproducibility for the percentages of heart rate reserve (%HRR), oxygen uptake reserve (%VO2R), and energy expenditure elicited during two bouts of MCT. Methods: Seven people aged 58 (12) yr, who previously had a stroke, performed a cardiopulmonary exercise test, a non-exercise control session, and two bouts of MCT. The MCT included 3 circuits of 10 resistance exercises at 15-repetition maximum intensity, with each set of resistance exercise interspersed with 45-s of walking. Expired gases were collected during the MCT and control session and for 40 min afterwards. Control session was necessary to calculate the net energy expenditure associated with each bout of MCT. Results: Mean %VO2R (1st MCT: 51.1%, P=0.037; 2nd MCT: 54.0%, P=0.009) and %HRR (1st MCT: 66.4%, P=0.007; 2nd MCT: 67.9%, P=0.010) exceeded the recommended minimum intensity of 40%. Both %VO2R (P=0.586 and 0.987, respectively) and %HRR (P=0.681 and 0.237, respectively) during the 1st and 2nd bouts of MCT were not significantly different to their corresponding gas exchange threshold values derived from cardiopulmonary exercise testing. Mean net total energy expenditure significantly exceeded the minimum recommend energy expenditure in the 1st (P=0.048) and 2nd (P=0.023) bouts of MCT. Between-day reproducibility for %HRR, %VO2R, and energy expenditure was excellent (ICC: 0.92-0.97). Conclusions: MCT elicited physiological strain recommended for improving health-related fitness in people after stroke and these responses demonstrated excellent between-day reproducibility.