Six-minute Step Test Research Articles

Validity and Responsiveness of the Manchester Fatigue Scale in Post-COVID

Objective: This study investigates the Manchester COPD Fatigue Scale's (MCFS) validity and responsiveness in individuals after hospitalization due to COVID-19.Methods: A longitudinal observational study included 53 adults diagnosed with COVID-19. Modified Medical Research Council dyspnea scale (mMRC), Six-Minute Step Test (6MST), Saint George's Respiratory Questionnaire (SGRQ), and Hospital Anxiety and Depression Scale (HADS) were assessed. The measurement properties tested were concurrent, convergent, discriminant validities, and responsiveness.Results: The MCFS showed concurrent, convergent, and discriminant validity, with moderate to strong significant correlations with fatigue (rs=0.57), symptoms (rs=-0.27), exercise performance (rs=0.39), depression (rs=0.67), and dyspnea (rs=0.44) measures. The instrument exhibited internal responsiveness with reduced fatigue scores three months after hospital discharge (median total score from 14.5 to 5.0,p<0.001). External responsiveness was shown through associations between MCFS scores and dyspnea changes. Conclusion: The MCFS is a valid and responsive tool for physicians and researchers in effectively identifying, monitoring, and managing post-COVID-19 fatigue.

Is the six-minute step test an alternative to six-minute walking test to assessment the functional capacity in elderly?

Is the six-minute step test an alternative to six-minute walking test to assessment the functional capacity in elderly?

The six-minute step test can predict COPD exacerbations: a 36-month follow-up study

The six-minute step test (6MST) has been shown to be effective in assessing exercise capacity in individuals with COPD regardless of severity and, despite its easy execution, accessibility and validity, information on the prognostic power of this test remains uncertain. The aim of this study is to investigate whether the 6MST can predict the occurrence of exacerbations in patients with COPD. This is a prospective cohort study with a 36-month follow-up in patients with COPD. All patients completed a clinical assessment, followed by pulmonary function testing and a 6MST. The 6MST was performed on a 20 cm high step; heart rate, blood pressure, oxygen saturation, BORG dyspnea and fatigue were collected. Sixty-four patients were included in the study, the majority being elderly men. Performance on the 6MST demonstrated lower performance compared to normative values proposed in the literature, indicating a reduced functional capacity. Kaplan Meier analysis revealed that ≤ 59 steps climbed during the 6MST was a strong predictor of COPD exacerbation over a 36-month follow-up. We have identified a minimal threshold number of steps (≤ 59) obtained through the 6MST may be able predict the risk of exacerbations in patients with COPD.

The phase angle cut-off point capable of discriminating hemodialysis patients with reduced exercise tolerance: a cross-sectional study

BackgroundPhase angle (PhA) is a prognostic marker of all-cause mortality in chronic kidney disease. However, no study has investigated this marker as a predictor of exercise intolerance in hemodialysis (HD) patients. The aim of this study was to determine a cut-off point for the PhA capable of discriminating HD patients with reduced exercise tolerance.MethodsThirty-one patients (80.6% men, median age 69 years) were included. The evaluations were performed on three different days, before the HD session. The outcomes evaluated were: biochemical markers, inflammatory and nutritional status, body composition, peripheral muscle strength and exercise tolerance. Performance ≤50% of the predicted value in the six-minute step test (6MST) was defined as reduced exercise tolerance.ResultsPatients presented an average of 67.6 steps (50.5% of predicted) in the 6MST. Fifteen patients (48.4%) were classified with reduced exercise tolerance. The receiver operating characteristic curve indicated a cut-off point of 3.73° for the PhA (sensitivity = 87%, specificity = 81%, and area under the curve = 0.88 [95% CI: 0.76–1.00]; p < 0.001). Patients with reduced exercise tolerance had worse inflammatory and nutritional status, lower PhA and greater impairment of peripheral muscle strength.ConclusionThe cut-off point of 3.73° for the PhA is sensitive and specific to discriminate HD patients with reduced exercise tolerance.Trial registrationThis study was registered in the Clinical Trials database (no. NCT03779126, date of first registration 19/12/2018).

Validade da Escala de Fadiga, Functional Assessment Of Chronic Illness Therapy Fatigue Scale (FACIT-F) em indivíduos com Doença Pulmonar Obstrutiva Crônica no Brasil

ABSTRACT Fatigue is one of the most prevalent symptoms in individuals with Chronic Obstructive Pulmonary Disease (COPD), but it is poorly evaluated. The Functional Assessment of Chronic Illness Therapy Fatigue Scale (FACIT-F) is one of the main instruments used to measure fatigue. However, this instrument has not yet been validated for the Brazilian population with COPD. This study aimed to investigate the validity of the FACIT-F fatigue scale in individuals with COPD. In a cross-sectional study, the impact of symptoms (COPD Assessment Test - CAT), dyspnea (modified Medical Research Council - MRC scale), functional capacity (six-minute step test - 6MST), exertional fatigue (Borg modified scale at the end of 6MST), and the FACIT-F scale to assess multidimensional fatigue were evaluated. Concurrent validity was assessed by associating the FACIT-F with the CAT, and convergent validity by associating it with the number of steps, perceived exertional fatigue, and dyspnea. Discriminant validity was assessed by comparing fatigue with the dyspnea severity strata. In total, 92 participants were studied (69.9±8.8 years, FEV1: 48.4% of predicted). The FACIT-F presented an average of 30.1±10.9 points, strong concurrent validity with the CAT (r=-0.80), strong convergent validity with dyspnea (r=−0.66), and low with exercise capacity (r=0.40) and fatigue on exertion (r=-0.44). FACIT-F was effective in discriminating groups with different intensities of dyspnea. Conclusion: The FACIT-F is a valid tool for assessing fatigue in the Brazilian population with COPD.

Os testes do degrau são viáveis, seguros e podem ser utilizados para avaliar a capacidade de exercício no domicílio após hospitalização por COVID-19

Abstract Introduction: Step-based tests are commonly utilized to assess the exercise capacity of individuals with respiratory diseases. However, the feasibility and safety of the step tests have not yet been studied in individuals after COVID-19. Objective: To investigate the feasibility and safety of the six-minute step test (6MST) and the modified incremental step test (MIST) in assessing exercise capacity at home in individuals after hospitalization for COVID-19, and to identify factors associated with performance in these tests. Methods: Cross-sectional multicenter study with individuals hospitalized for COVID-19 fifteen days after hospital discharge. Participants performed spirometry, 6MST, and MIST during a single home visit. Adverse events were registered during and immediately after the tests. Results: Sixty-five participants were studied (50 ± 10 years old, 55% male). The feasibility was 96.9% and the incidence of adverse events was 13.8% in 6MST and 6.2% in MIST. The individuals performed 76.9% of the predicted on the 6MST, with 40% of the participants reaching 80% of the maximum HR and 31% presenting exercise-induced oxygen desaturation. In the MIST, the individuals performed 20% of the predicted, 23% of the participants reached 80% of the maximum heart rate, and 17% presented exercise-induced oxy-gen desaturation. Length of hospital stay and the use of mechanical ventilation were associated with test performance. Conclusion: 6MST and MIST are feasible, safe, and can be used to assess exercise capacity in a home environment in individuals after hospitalization for COVID-19. The performance in these tests was associated with a prolonged hospital stay and the use of mechanical ventilation.

Functional recovery of chronically critically ill patients in the first days after discharge from the intensive care unit: Feasibility of the 6-minute step test.

Survivors of chronic critical illness often experience weakness and functional dependence to various degrees after their intensive care unit (ICU) stay. Evaluating their functional status with the traditional six-minute walk test is challenging due to space constraints or patient intolerance. Our aim was to evaluate the feasibility of using the six-minute step test (6MST) as a measure of functional capacity in chronically critically ill patients early after ICU discharge. This prospective study was undertaken in a private Brazilian hospital. From July 2019 to July 2020, all chronically critically ill patients were asked to participate 48 hours after ICU discharge. On the day of study inclusion and a week later, those who consented underwent functional assessment comprised of the 6MST, peripheral muscle strength using handgrip strength (HGS), and mobility using the ICU mobility scale (IMS). A total of 40 patients were included. The 6MST was feasible in 40% on the first evaluation and 57% on the second. The median 6MST was 0 [0-5] on the first evaluation and 3.5 [0-7.75] on the second (P = 0.005). The median HGS increased from 11.50 [9.25-18] on the first evaluation to 14.5 [10-20] on the second (P = 0.006). The median IMS was 4.5 [3.25-7] on the first evaluation and 6 [3.25-7] on the second (P<0.001). Despite the significant improvement, all parameters measured remained well below normal. The 6MST was a feasible measure of functional capacity in chronically critically ill patients early after ICU discharge. Patients had functional capacity well below predicted values.

Six-minute step test performance in asymptomatic adults

The objectives of this study were i) to measure a six-minute step test (6MST) in asymptomatic adults; ii) to determine the applicability of Arcuri et al.’s reference equation to Indian adults; iii) to develop a prediction equation for Indian adults. 110 adult males and females aged 18-40 years were recruited for this prospective cross-sectional study conducted in India. Participants underwent 6MST. Applicability was assessed by comparing the findings of the 6MST with the values derived from Arcuri et al.’s predicted equations using the Bland-Altman plot. A multiple regression analysis was used to develop the prediction equation. The mean±SD six-minute step count was 159.42±17.60 steps and 150.78±14.39 steps in males and females respectively. The 6MST for males can be determined by males (steps)=204.371-1.521×age(years) and females (steps)=179.567-1.06×age (years). Arcuri et al.’s equation cannot be used to predict 6MST in Indian adults. Region-specific equations are useful to assess the values.

Cardiorespiratory Response to Six-Minute Step Test in Post COVID-19 Patients-A Cross Sectional Study.

New coronavirus disease 2019 (COVID-19) can cause persistent symptoms and physical weakness that can lead to a limitation in activities of daily living (ADL). There is a lack of evidence about the performance in the six-minute step test (6MST) of post-COVID-19 patients and healthy subjects. The aim of this study is to investigate the cardiorespiratory response induced by the 6MST in post-COVID-19 patients and compare it with the response of the six-minute walk test (6MWT). This cross-sectional study was conducted on 34 post-COVID-19 patients and 33 healthy subjects. The assessment was performed at one month from a non-severe SARS-CoV-2 infection. Both groups were assessed by using the 6MST, 6MWT, and the pulmonary function test (PFT). Post COVID functional status (PCFS) scale was used for the post-COVID-19 group to assess functional status. Physiological responses; heart rate (HR), respiratory rate (RR), oxygen saturation (SpO2), blood pressure (BP), and Borg scale for fatigue and dyspnea were recorded before and after the 6MST and 6MWT. the performance of the post-COVID-19 group was worse than the healthy group in both tests. In 6MWT, the distance walked by the post-COVID-19 group (423 ± 7) was 94 m less than the healthy group, and the number of climbed steps in the 6MST (121 ± 4) was 34 steps less than the healthy group. Both results were statistically significant (p < 0.001). There was a moderate positive correlation between the 6MST and 6MWT in walked distance versus steps number (r = 0.5, p < 0.001). In addition, there was a moderate correlation between the two tests in the post (HR, RR, SpO2, systolic blood pressure SBP, diastolic blood pressure DBP, dyspnea, and fatigue) with p < 0.001. Six-minute step tests produced similar cardiorespiratory responses when compared to a 6MWT. The 6MST can be used as an assessment tool for COVID-19 patients to evaluate their functional capacity and ADL.

Is the six-minute step test able to reflect the severity and symptoms based on cat score?

BackgroundThis is the first study to investigate the performance of 6MST in COPD patients divided into different symptom severity groups based on the CAT questionnaire score. ObjectivesTo evaluate the relationship between the degree symptomatology using the chronic obstructive pulmonary disease (COPD) Assessment Test (CAT) with the six- minute step test (6MST) in COPD patients. METHODS: This is a cross-sectional study in which 59 patients with COPD were evaluated. The groups were stratified according to the subsequent cutoff points: CAT <10 (little impact) n= 22; CAT 11-20 (moderate impact) n=20; CAT <20 (large impact) n=17. During 6MST the individuals were instructed to go up and down a single step with a height of 20 centimeters (cm). ResultsComparing the groups in relation to performance on the 6MST, the number of climbs on the step were significantly higher in the CAT group <10 when compared to the CAT group >20, the variation in HR between rest and peak exercise (∆ HRpeak- rest) was lower in the CAT>20 group compared to the CAT<10 group and the CAT 11- 20 group. We found direct relationships between the number of ascents and descents in the 6MST vs the CAT score (r=0.35, p=0.007); and 6MST vs degree of obstruction of %FEV1 (r-0.46, p=0.002) We verified a linear regression model in which the FEV1 (L) and the CAT score influenced 29% in the performance of the 6MST. ConclusionThe COPD severity represented by the FEV1 and the CAT score are associated and influenced by 29% the performance of 6-minute step test. Our findings may have important implications for the clinical evaluation of these patients as well as for rehabilitation.

Normative values and reference equation for the six-minute step test to evaluate functional exercise capacity: a multicenter study

ABSTRACTObjective:To establish normative values and a reference equation for the number of steps climbed during the six-minute step test (6MST) in healthy adults, and to assess the reliability of the test and of the equation. Methods:This was a multicenter cross-sectional study involving 468 healthy volunteers (age range: 18-79 years) recruited from the general community in six research laboratories across different regions of Brazil, which is a country with continental dimensions. The 6MST was performed twice (30-min interval), and clinical, demographic, and functional variables were evaluated. An independent sample of 24 volunteers was evaluated to test the reference equation a posteriori. Results:The number of steps had excellent test-retest reliability (intraclass correlation coefficient = 0.96 [95%CI: 0.95-0.97]), and the mean number of steps was 175 ± 45, the number being 14% greater in males than in females. The best performance on the test was correlated with age (r = −0.60), sex (r = 0.28), weight (r = 0.13), height (r = 0.41), BMI (r = −0.22), waist circumference (r = −0.22), thigh circumference (r = 0.15), FVC (r = 0.54), and physical activity level (r = 0.17; p < 0.05 for all). In the regression analysis, age, sex, height, and weight explained 42% of the variability of the 6MST. Normative values were established for the 6MST according to age and sex. There was no difference between the 6MST values from the independent sample and its predicted values (157 ± 29 steps vs. 161 ± 25 steps; p = 0.47; 97% of predicted values). Conclusions:The normative values and the reference equation for the 6MST in this study seem adequate to accurately predict the physical functional performance in adults in Brazil.

Avaliação da capacidade física em pacientes hospitalizados com diagnóstico de COVID-19

ABSTRACT SARS-CoV-2 infection can cause severe acute respiratory syndrome (SARS), leading to hypoxemia. Physical capacity assessment can be performed before hospital discharge using submaximal exercise testing. This study sought to assess physical capacity and exercise tolerance with the six-minute step test (6MST) in hospitalized COVID-19 patients who required oxygen (O2) support during hospitalization. A prospective, interventional study was conducted with patients aged from 18 to 90 years who required oxygen therapy during hospitalization. Assessment was performed using Perme Score, followed by the 6MST tests, assessing the peripheral oxygen saturation (SpO2), heart rate (HR), blood pressure (BP), and subjective exertion perception by Borg Scale, before and immediately after the 6MST. A total of 31 patients, with a mean age of 51.9 years, were evaluated. Nasal cannula (NC) was the most used device (64.5% of patients). Regarding HR, BP, and Borg Scale, their mean value increased after 6MST. SpO2 showed a lower mean value after 6MST. Out of the 86.9% of patients who completed the test, 48.3% completed it with interruptions, and 12.9% had to suspend it. The 6MST was able to assess physical capacity and exercise tolerance, proving to be an effective tool for evaluating COVID-19 patients.

Reference equations of oxygen uptake for the step test in the obese population.

The aim of this study was to establish reference equations for the six-minute step test (6MST) based on demographic, anthropometric, body composition, and performance variables able to predict oxygen uptake (V̇O2) in obese individuals. Seventy-three obese adults (42±14 years old, body mass index >30 kg/m2) from both sexes were included. They underwent anamnesis, body composition evaluation, and the 6MST with expired gases registered simultaneously. Three equations were developed for the obese population (n=73; 59% female). The first equation was composed of the up-and-down step cycles (UDS), sex, and age as predictors; the second equation was composed of the UDS, age, and lean mass (LM). Both equations collectively explained 68.1% of the V̇O2 variance in the 6MST, while the third equation, composed of the UDS, age, and body mass, accounted for 67.7% of the V̇O2 variance. UDS, sex, age, LM, and body mass were important V̇O2 predictors of 6MST in these obese individuals. This study contributes to the dissemination of a simple, inexpensive, and fast evaluation method that can provide important indicators of cardiorespiratory fitness and guide strategies for rehabilitation.

Validação do constructo e reprodutibilidade intra-avaliador do teste de degrau de 6 minutos em crianças saudáveis de 7-11 anos

Objetivo: Validar o teste de degrau de seis minutos (TD6M) e avaliar sua reprodutibilidade para determinação da tolerância ao esforço em crianças saudáveis de 7-11 anos. Métodos: Foram incluídas na pesquisa 66 crianças saudáveis, com idade entre 7 e 11 anos completos. Os voluntários foram submetidos ao teste de caminhada de seis minutos (TC6M) e ao TD6M, em ordem aleatória e dias diferentes, com intervalo de no máximo sete dias. Resultados: Foi observada uma correlação positiva moderada entre a distância percorrida no TC6M e o número de subidas no TD6M (r=0,43; p&lt;0,001). A reprodutibilidade das variáveis no TD6M foi considerada excelente em relação às variáveis desempenho (número de degraus) (r=0,92; IC=0,87 a 0,87; p&lt;0,001), pressão arterial sistólica (PAS) imediatamente após (r=0,87; IC=0,79 a 0,92; p&lt;0,001), PAS-1’recuperação (r=0,84; IC=0,74 a 0,90; p&lt;0,001), frequência cardíaca (FC) máxima (r=0,90; IC=0,83 a 0,94; p&lt;0,001), FC-imediatamente após (r=0,88; IC=0,81 a 0,93; p&lt;0,001) e Fadiga de membros inferiores (MMII)-durante o teste (3o min) (0,86; IC=0,78 a 0,92; p&lt;0,001). Apresentaram também uma reprodutibilidade muito boa a PAS-repouso (r=0,75; IC=0,59 a 0,84; p&lt;0,001), PAS-5’recuperação (r=0,78; IC=0,56 a 0,83; p&lt;0,001), PAD-repouso (r=0,74; IC=0,58 a 0,84; p&lt;0,001), pressão arterial diastólica (PAD) imediatamente após (r=0,72; IC=0,55 a 0,83; p&lt;0,001), PAD-1’recuperação (r=0,77; IC=0,63 a 0,86; p&lt;0,001), PAD-5’recuperação (r=0,73; IC=0,56 a 0,83; p&lt;0,001), FC-repouso (r=0,73; IC=0,60 a 0,86; p&lt;0,001), Fadiga de MMII-imediatamente após (r=0,72; IC=0,54 a 0,83; p&lt;0,001). Conclusão: O TD6M é seguro, válido e com boa reprodutibilidade intra-avaliador na avaliação da tolerância ao esforço em crianças saudáveis entre 7-11 anos.

The Six-Minute Step Test as a Predictor of Functional Capacity according to Peak VO2 in Cardiac Patients.

ResumoFundamento:O teste do degrau de seis minutos (TD6) é uma forma simples de avaliar a capacidade funcional, embora tenha sido pouco estudado em pacientes com doença arterial coronariana (DAC) ou insuficiência cardíaca (IC).Objetivo:Analisar a associação entre o TD6 e o consumo de oxigênio de pico (VO2pico) e desenvolver uma equação que estime o VO2pico com base no TD6, bem como determinar um ponto de corte para o TD6 que preveja um VO2pico ≥ 20 mL.kg-1.min-1Métodos:Nos 171 pacientes submetidos ao TD6 e a um teste de exercício cardiopulmonar, análises da curva ROC, de regressão e de correlação foram usadas, e um p < 0,05 foi admitido como significativo.Resultados:A idade média foi 60±14 anos, e 74% eram do sexo masculino. A média da fração de ejeção ventricular esquerda foi 57±16%; 74% apresentavam DAC, e 28%, IC. A média do VO2pico foi 19±6 mL.kg-1.min-1, e o desempenho médio do TD6 foi 87±45 passos. A associação entre o TD6 e o VO2pico foi r 0,69 (p < 0,001). Os modelos VO2pico = 19,6 + (0,075 x TD6) – (0,10 x idade) para homens e VO2pico = 19,6 + (0,075 x TD6) – (0,10 x idade) – 2 para mulheres poderiam prever o VO2pico com base nos resultados do TD6 (R ajustado 0,72; R2 ajustado 0,53). O ponto de corte mais acurado para que o TD6 preveja um VO2pico ≥ 20 mL.kg-1.min-1 foi de > 105 passos [área sob a curva 0,85; intervalo de confiança de 95% 0,79 - 0,90; p < 0,001].Conclusão:Uma equação que preveja o VO2pico com base nos resultados do TD6 foi derivada, e foi encontrada uma associação significativa entre o TD6 e o VO2pico. O ponto de corte do TD6, que prevê um VO2pico ≥ 20 mL.kg-1.min-1, foi > 105 passos. (Arq Bras Cardiol. 2021; 116(5):889-895)

Relationship of phase angle and peak torque of knee extensors with the performance in six-minute step test in haemodialysis patients

BackgroundChronic kidney disease is a systemic disease affecting not only renal function, but also endocrine, cardiovascular, and skeletal muscle systems, with broad impact on functionality. Therefore, the assessment of body composition, peripheral muscle function, and exercise tolerance is also of great importance in this population. In addition, the development of reliable strategies that use feasible tools in clinical practice is of great importance in the functional diagnosis, clinical management and prescription of physical activity.ObjectiveTo assess the relationship between phase angle and peak torque of knee extensors with the performance in six-minute step test of patients with chronic kidney disease undergoing haemodialysis.MethodsObservational and cross-sectional study at Haemodialysis Centre of Sírio-Libanês Hospital. The evaluations took place 3 days before the haemodialysis sessions. On the first day, patients underwent anthropometric evaluation and biochemical tests (lactate, urea, creatinine, albumin, ferritin and growth factor similar to insulin type 1 [IGF1]). On the second day, performed electrical bioimpedance and exercise tolerance assessed using the six-minute step test. On the last day, the evaluation of knee extensor muscles strength using isokinetic dynamometry was performed.ResultsEighteen subjects were included, with a mean age of 62.3 ± 17.6 years. A positive linear correlation was observed between the phase angle, derived from the electrical bioimpedance, and the performance in six-minute step test in these patients. It was also possible to observe a linear correlation between phase angle and IGF1, handgrip strength, peak torque of knee extensors and quality of life questionnaire. The peak torque of knee extensors also presented a linear correlation with IGF1, the performance in six-minute step test and mal-nutrition and inflammation score.ConclusionPhase angle and peak torque of knee extensors were correlated with the performance in six-minute step test. Therefore, the phase angle seems to be an important marker of reduced peripheral muscle function and exercise tolerance in haemodialysis patients.

Performance, metabolic, hemodynamic, and perceived exertion in the six-minute step test at different heights in a healthy population of different age groups

Abstract Aim: This study aimed to compare the performance, metabolic, hemodynamic, and perceived exertion during the 6-minute step test (6MST) conducted with different step heights in healthy subjects and also to compare the performance between different age groups for each step height. The association between age, body mass index, level of physical activity, and lower limb measurements with performance were also evaluated. Methods: This is a cross-sectional study. Anthropometric measures, physical performance, and cardiovascular stress were evaluated during a self-paced 6MST with different step heights in healthy subjects in the age group of 18-59. All the participants underwent three-step tests (15 cm, 20 cm, and 30 cm) on the same day, in a randomized order. Results: Forty participants (20 men and 20 women) performed the tests. The performance in the test for the highest step was significantly lower compared to the step with the lowest height (152 ± 24 vs. 173 ± 27 and 184 ± 33; p < 0,05). The estimated peak oxygen consumption (VO2peak) increased by ∼2.5 mL.kg−1·min−1 with the increase in step height. Hemodynamic variables, such as percent of maximum heart rate (%HRmax), and systolic blood pressure increased as the step height increased. There was a fair correlation between performance and the level of physical activity in the test with a step height of 15 cm and 20 cm. Conclusion: A higher step height caused greater cardiovascular stress, without exceeding the submaximal levels of the test, indicating that the 6MST can be used as an accurate instrument for evaluating aerobic capacity in healthy individuals.

Reliability and validity of six-minute step test in patients with heart failure.

Exercise intolerance is the hallmark consequence of advanced chronic heart failure (HF). The six-minute step test (6MST) has been considered an option for the six-minute walk test because it is safe, inexpensive, and can be applied in small places. However, its reliability and concurrent validity has still not been investigated in participants with HF with reduced ejection fraction (HFrEF). Clinically stable HFrEF participants were included. Reliability and error measurement were calculated by comparing the first with the second 6MST result. Forty-eight hours after participants underwent the 6MST, they were invited to perform a cardiopulmonary exercise test (CPET) on a cycle ergometer. Concurrent validity was assessed by correlation between number of steps and peak oxygen uptake (V̇O2 peak) at CPET. Twenty-seven participants with HFrEF (60±8 years old and left ventricle ejection fraction of 41±6%) undertook a mean of 94±30 steps in the 6MST. Intra-rater reliability was excellent for 6MST (ICC=0.9), with mean error of 4.85 steps and superior and inferior limits of agreement of 30.6 and -20.9 steps, respectively. In addition, strong correlations between number of steps and CPET workload (r=0.76, P<0.01) and peak V̇O2 (r=0.71, P<0.01) were observed. From simple linear regression the following predictive equations were obtained with 6MST results: V̇O2 peak (mL/min) = 350.22 + (7.333 × number of steps), with R2=0.51, and peak workload (W) = 4.044 + (0.772 × number of steps), with R2=0.58. The 6MST was a reliable and valid tool to assess functional capacity in HFrEF participants and may moderately predict peak workload and oxygen uptake of a CPET.

Measurement properties of step tests for exercise capacity in COPD: A systematic review

Objective: To determine the level of evidence of the measurement properties (validity, reliability, and responsiveness) and interpretability of the step tests available for assessing the exercise capacity in patients with chronic obstructive pulmonary disease. Data sources: The data sources Web of Science, MEDLINE, PubMed, PEDro, CENTRAL of Cochrane Library, and Scopus were searched up to June 26, 2020. Review methods: Studies of any design that reported results for any measurement property of the step tests for assessing the exercise capacity in COPD patients were selected. One reviewer extracted the data, and two reviewers independently rated the level of evidence by using the Consensus-Based Standards for the Selection of Health Measurements Instruments recommendations. Results: Thirty-one studies were included in the data synthesis. Chester Step Test, Modified Incremental Step Test, two-, three-, four-, and six-Minute Step Test, Paced Step Test, and six-Minute Stepper Test were identified. A step test protocol was also found. The level of evidence of their results for the measurement properties was mostly determined as “low” to “very low.” The best level of evidence found was for the six-minute stepper test: “high” on construct validity (r = 0.56–0.71); and “moderate” on criterion validity (r = 0.36–0.69), and responsiveness (r = 0.26–0.34). Conclusion: The general level of evidence of the measurement properties of the step tests is “low” to “very low” for assessing exercise capacity in patients with chronic obstructive pulmonary disease, which can limit their application in clinical practice. The six-minute Stepper Test is currently the most appropriate step test available.

Impaired performance of women with patellofemoral pain during functional tests

ObjectiveTo compare the performance, reliability, and validity of functional tests between women with and without patellofemoral pain. MethodsTwenty women with a diagnosis of patellofemoral pain between 18 and 40 years of age and 20 age-matched pain-free controls participated in the study. All participants performed a set of five function tests: sitting-rising test, sit-to-stand in 30 seconds, stair-climb test, stair descent test, and six-minute step test. To investigate reliability, participants were assessed on two different days, seven days apart, by two independent investigators blinded to the results of the other investigator. Validity was evaluated through associations with the results on the Anterior Knee Pain Scale. ResultsPerformance in the tests was worse in women with patellofemoral pain than in the control group for the sit-to-stand in 30 seconds (mean difference [MD] 3.4reps; 95%CI: 0.4, 6.4), stair-climb test (MD: 0.36s; 95%CI: 0.1, 0.63), and six-minute step test (MD: 45reps; 95%CI: 20, 70). No differences were observed for the sitting-rising and stair descent tests. All tests in both groups showed moderate to excellent intra- and inter-rater reliability (intraclass correlation coefficients: 0.61 to 0.91 and 0.72 to 0.96, respectively). Finally, only the results on the sit-to-stand in 30 seconds test correlated with the Anterior Knee Pain Scale (r=0.44, p=0.047) in the patellofemoral pain group. ConclusionWomen with patellofemoral pain present lower performance on some functional tests. Functional tests are reliable in patients with patellofemoral pain, although they are not associated with the results on the Anterior Knee Pain Scale self-questionnaire.