Is the Short and Fast Step Test a safe and feasible tool for exploring anaerobic capacities of individuals with coronary heart disease in clinical practice?

Background While its importance in daily living, the anaerobic metabolism is not taken into account in clinical practice. The lack of validated functional performance tests for patients with chronic disabilities may explain this defect. In this context, the Short and Fast Step Test (SFST) was recently developed and validated in healthy volunteers. Aim The purpose of this study was to investigate the safety, feasibility and reliability of the SFST, a functional test exploring anaerobic metabolism in coronary patients during cardiac rehabilitation. Design This study was a monocentric prospective study. Settings This study took place in the rehabilitation center of the University Hospital Center of Dijon, France. Population 44 coronary patients, addressed for a first cardiac rehabilitation, were included in this protocol. Methods All participants performed three SFST: T1 and T2 (including respiratory gas exchange) the first day of the program and T3 after 3 to 7 days. SFST consists of walking up and down a 17.5cm-high step as many times as possible in 1 minute. Safety was assessed by the percentage of patients who performed the SFST without reporting a fall, or muscular or cardiovascular events. Feasibility was evaluated by the percentage of patients who succeeded in doing the SFST. Reliability was assessed with the number of raised steps in same condition (T1-T3) and different conditions (T1-T2) using a 2-way intraclass correlation coefficient (ICC). Values were given with their 90% confidence interval [90%CI]. Results The safety was 95.2% [85.8;99.2] for T1, 88.1% [76.6;95.2] for T2 and 90.4% [79.5;96.7] for T3. 100% [93,1;100] of participants completed T1 and T2, 92.9% [82.6;98] T3. An ICC of 0.74 [0.60;0.84] was observed between T1 and T3 and of 0.87 [0.79;0.92] between T1 and T2. Conclusions This study demonstrates the good safety, feasibility and reliability of the SFST to assess anaerobic metabolism in coronary patients in a rehabilitation program. Clinical rehabilitation impact These results show that the SFST seems suitable for the evaluation of brief submaximal functional capacity in daily activities. It offers a real possibility to assess such capacity during the cardiac rehabilitation routine.