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. SETTING: This study took place in the rehabilitation center of the University Hospital Center of Dijon, France. POPULATION: Forty-four 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 17.5 cm-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.

Number of raised steps: A tool to assess brief and intense effort involving anaerobic metabolism.

BACKGROUND: Although the initial anaerobic component of exercise adaptation is unavoidable, no specific functional test is available for use in routine non-sporting practice to evaluate it. OBJECTIVE: To assess the bioenergetic and biomechanical properties of the Short and Fast Step Test (SFST), which consists of walking up and down a step as many times as possible in 1minute and to analyse its ability to explore the initial anaerobic component of effort in comparison to a reference self-paced step test. METHODS: Overall, 31 healthy subjects (19 women; mean [SD] age, 32.4 [10.2] years) completed a test-retest of a self-paced step test and the SFST, with pre- and post-test measurement of blood lactate concentration and continuous recording of VO2 and modelling of excess post-exercise oxygen consumption (EPOC), near-infrared spectroscopy (NIRS) of the quadriceps and mechanical power (estimated by the number of steps climbed and 3-D motion analysis). RESULTS: Both step tests were well tolerated. The reliability of the bioenergetics parameters, number of raised steps, mechanical power and NIRS tissue saturation index was good. Indirect mechanical power (estimated from number of steps) was correlated with direct power (computed from the centre of mass). Lactate accumulation was significantly increased during exercise with only the SFST (mean [SD] increase, 3.86 [3.26]mmolL-1 from resting values, P<0.05). EPOC was higher with the SFST than the self-paced step test (P<0.05). Only the SFST showed significant correlations between number of steps climbed and EPOC (r=0.84; P<0.001) and decreased tissue saturation index (NIRS) and EPOC area (r=-0.39; P<0.05). CONCLUSIONS: SFST is feasible, well tolerated, reliable and responsive to explore a brief exercise involving anaerobic metabolism at submaximal intensity. The number of steps taken in 1minute seems a suitable parameter for practical application.

Assessment tools for personalizing training intensity during cardiac rehabilitation: Literature review and practical proposals.

Exercise training, associated with therapeutic education, is the main axis of cardiac rehabilitation (CR) programs. The aim of this study was to review the literature for descriptions of the various assessments of exercise tolerance used to prescribe exercise intensity during CR. A secondary objective was to attempt to formulate a rational practice with these assessments in CR programs.

Fixed-distance walk tests at comfortable and fast speed: Potential tools for the functional assessment of coronary patients?

OBJECTIVES: There is ambiguity concerning the walk tests available for functional assessment of coronary patients, particularly for the walking speed. This study explores the psychometric properties of two walking tests, based on fixed-distance tests, at comfortable and fast velocity, in stabilized patients at the end of a cardiac rehabilitation program. METHODS: At a three-day interval 58 coronary patients (mean age of 64.85±6.03 years, 50 men) performed three walk tests, the first two at a comfortable speed in a random order (6-minute walk test - 6MWT - and 400-metre comfortable walk test - 400mCWT) and the third at a brisk speed (200-metre fast walk test - 200mFWT). A modified Bruce treadmill test was associated at the end of the second phase. Monitored main parameters were: heart rate, walking velocity, VO2. RESULTS: Tolerance to the 3 tests was satisfactory. The reliability of the main parameters was good (intraclass correlation coefficient>0.8). The VO2 concerning 6MWT and 400mCWT were not significantly different (P=0.33) and were lower to the first ventilatory threshold determined by the stress test (P<0.001): 16.2±3.0 vs. 16.5±2.6 vs. 20.7±5.1mL·min-1·kg-1 respectively. The VO2 of the 200mFWT (20.2±3.7) was not different from the first ventilatory threshold. CONCLUSIONS: 400mCWT and 200mFWT are feasible, well-tolerated and reliable. They explore two levels of effort intensity (lower and not different to the first ventilatory threshold respectively). 400mCWT is a possible alternative to 6MWT. Associated with 200mFWT it should allow a better measurement of physical capacities and better customization of exercise training.

Effects of an eccentric training personalized by a low rate of perceived exertion on the maximal capacities in chronic heart failure: a randomized controlled trial.

BACKGROUND: The eccentric (ECC) training, in spite of its potential interest (slightest request of the cardiorespiratory system) compared with the concentric (CON) training, is not applied during the rehabilitation of the chronic heart failure (CHF). The main reasons are the difficulty personalizing the ECC exercises by avoiding the muscle complications and the lack of information concerning the specific effects on the maximal capacities in CHF patients. AIM: To compare - following a prior study on the feasibility and on the functional impacts - the effects on maximal capacities and tolerance in CHF of ECC training tailored by a low rate of perceived exertion (RPE) and those of conventionally tailored CON training. DESIGN: Prospective randomized comparative study. SETTING: A Rehabilitation Department in a University Hospital. POPULATION: CHF outpatients with reduced ejection fraction randomized to either ECC (N.=21) or CON training (N.=21). METHODS: ECC and CON training were respectively tailored by a low RPE (RPE between 9 and 11 on the Borg scale) and a heart rate (HR) corresponding to the first ventilatory threshold. Cardiopulmonary exercise test, maximal muscle strength tests (quadriceps, triceps surae) and 6-minute walk test were performed before and after training. Tolerance to training was assessed by RPE, muscle soreness, increase of HR, blood pressure and plasma NT-proBNP. RESULTS: Improvement in peak work rate was similar for both groups (+20%, P<0.01), but VO2 peak and VO2 at the first ventilatory threshold were only increased in the CON group (+13.5%, P<0.01). Maximal strength of the triceps surae was increased in the ECC group only (+23%, P<0.01). Improvement in the walk test distance was similar in both groups, but the corresponding VO2 was only increased after CON training. Tolerance to training was good in both groups, except higher increment of training HR in the CON group (P<0.05). CONCLUSIONS AND CLINICAL REHABILITATION IMPACT: ECC training tailored by a low RPE is well tolerated in CHF patients and induces an improvement in maximal capacities similar to that with conventional CON training despite lower demands on the cardiorespiratory system, showing a better energetic efficiency, potentially interesting for these patients with reduced energetic reserve.