A study of the 200-metre fast walk test as a possible new assessment tool to predict maximal heart rate and define target heart rate for exercise training of coronary heart disease patients.

OBJECTIVE: To develop a new predictive model of maximal heart rate based on two walking tests at different speeds (comfortable and brisk walking) as an alternative to a cardiopulmonary exercise test during cardiac rehabilitation. DESIGN: Evaluation of a clinical assessment tool. SETTING: A Cardiac Rehabilitation Department in France. SUBJECTS: A total of 148 patients (133 men), mean age of 59 ±9 years, at the end of an outpatient cardiac rehabilitation programme. MAIN MEASURES: Patients successively performed a 6-minute walk test, a 200 m fast-walk test (200mFWT), and a cardiopulmonary exercise test, with measure of heart rate at the end of each test. An all-possible regression procedure was used to determine the best predictive regression models of maximal heart rate. The best model was compared with the Fox equation in term of predictive error of maximal heart rate using the paired t-test. RESULTS: Results of the two walking tests correlated significantly with maximal heart rate determined during the cardiopulmonary exercise test, whereas anthropometric parameters and resting heart rate did not. The simplified predictive model with the most acceptable mean error was: maximal heart rate = 130 - 0.6 × age + 0.3 × HR200mFWT (R(2) = 0.24). This model was superior to the Fox formula (R(2) = 0.138). The relationship between training target heart rate calculated from measured reserve heart rate and that established using this predictive model was statistically significant (r = 0.528, p < 10(-6)). CONCLUSIONS: A formula combining heart rate measured during a safe simple fast walk test and age is more efficient than an equation only including age to predict maximal heart rate and training target heart rate.

Determining the minimal clinically important difference for the six-minute walk test and the 200-meter fast-walk test during cardiac rehabilitation program in coronary artery disease patients after acute coronary syndrome.

OBJECTIVE: To estimate the minimal clinically important difference (MCID) for the 6-minute walk test (6MWT) and the 200-m fast-walk test (FWT) in patients with coronary artery disease (CAD) during a cardiac rehabilitation program. DESIGN: Prospective study using distribution- and anchor-based methods. SETTING: Outpatients from a cardiac rehabilitation unit. PARTICIPANTS: Stable patients with CAD (N=81; 77 men; mean±SD age, 58.1±8.7y) enrolled 31±12.1 days after an acute coronary syndrome (ACS). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: 6MWT and 200-m FWT results before and after an 8-week cardiac rehabilitation program and at the 6th and 12th sessions. Patients and physiotherapists who supervised the training were asked to provide a global rating of perceived change in walking ability while blinded to changes in walk test performances. RESULTS: Mean change in 6MWT distance (6MWD) in patients who reported no change was -6.5m versus 23.3m in those who believed their performance had improved (P<.001). This result was consistent with the MCID determined by using the distribution method (23m). Considering a 25-m cutoff, positive and negative predictive values were 0.9 and .63, respectively. Conversely, there was no difference in 200-m FWT performance between these 2 groups (0.1 vs -1.4s, respectively). There was poor agreement with the physiotherapist's perceived change. CONCLUSIONS: The MCID for 6MWD in patients with CAD after ACS was 25m. This result will help physicians interpret 6MWD change and help researchers estimate sample sizes in further studies using 6MWD as an endpoint.

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.

Neuromuscular adaptations to low-frequency stimulation training in a patient with chronic heart failure.

Electrical myostimulation (EMS) has recently been proposed as an interesting rehabilitation tool in patients with chronic heart failure (CHF). Although its beneficial effects on exercise capacity and muscle strength have been demonstrated, the neuromuscular adaptations responsible for improved performance are not well understood. This preliminary case report was therefore planned to investigate the neural and muscular adaptations to a 5-wk EMS program in one patient. An increase in maximal strength (10.5%) was accompanied by increased twitch torque (13.9%) and slowing of muscle contractile properties (half-relaxation time, time to peak torque, and maximal rate of relaxation increased by 7.1, 31.1, and 16.6%, respectively) without changes in muscle activation. This preliminary case report therefore shows that in a highly deconditioned patient, EMS training improved strength through muscular adaptations rather than by neural changes, suggesting that EMS may be valuable for counterbalancing loss of muscle strength and function common in CHF patients.

Comparison of low-frequency electrical myostimulation and conventional aerobic exercise training in patients with chronic heart failure.

BACKGROUND: Physical training is recommended as an efficient therapy in patients with chronic heart failure (CHF). Low-frequency electrical myostimulation (EMS) has recently been suggested as a good alternative to conventional aerobic training. The aim of this study was to compare the effects of EMS and conventional exercise training in patients with moderate to severe CHF. METHODS: Twenty-four patients with stable CHF (56.7+/-7.3 years, New York Heart Association grades II and III) underwent 5 weeks of exercise training, 5 h a week, using EMS (n=12) or conventional (n=12) training programmes. At baseline and after the training period, patients performed a symptom-limited cardiopulmonary test, a 6-min and a 200-m walk exercises and an evaluation of maximal knee extensor strength. RESULTS: Oxygen uptake (VO2) and workload at the end of exercise (peak values) and at ventilatory threshold increased after EMS (P< or =0.05) and conventional exercise (P<0.05) training programmes. The slope of the relationship between VO2 and workload was reduced after EMS (P<0.05). The time to recover half of peak VO2 decreased irrespective of the training programme (P<0.001). EMS and conventional exercise training programmes also increased the maximal knee extensor strength (P<0.05), the distance walked in 6 min (P<0.01) and decreased the time elapsed to cover 200 m (P<0.05). These improvements were not statistically different between EMS and conventional exercise. CONCLUSION: In patients with moderate to severe CHF, 5 weeks of EMS and conventional exercise training produce similar improvements to exercise capacity and muscle performance.