Procedures and measurement properties of the 6-min step test: A systematic review with clinical recommendations.

OBJECTIVE: To provide information regarding the procedures, safety, tolerability, and measurement properties of the 6-min step test. DATA SOURCES: MEDLINE, EMBASE, CINAHL, and SPORTDiscus (from inception until January 2024). REVIEW METHODS: Studies that examined adults with acute or chronic diseases, and outcomes related to procedures, safety, tolerability, or measurement properties of the 6-min step test were included. Outcome data were summarized and combined in meta-analyses. The quality of included studies was assessed by the Consensus-based Standards for the selection of health Measurement Instruments checklist, and the quality of evidence was determined according to the Grading of Recommendations Assessment, Development, and Evaluation system. RESULTS: Fourteen studies, involving 847 participants, were included. All studies performed the 6-min step test in 6 min; however, some studies varied the step height and the use of upper limb support. The test appears to be safe and well tolerated by individuals. Moderate- to high-quality evidence demonstrated appropriate results for test-retest reliability (4 studies; Intraclass correlation coefficient 0.96; 95% CI 0.91-0.98; n = 125), criterion validity (4 studies; r = 0.53; 95% CI 0.30-0.71; n = 307), and construct validity (4 studies; r = 0.63; 95% CI 0.52-0.73; n = 233). CONCLUSION: This review provides recommendations for applying the 6-min step test in clinical and research settings. No adverse events were reported, and the test appears to be well tolerated. Adequate results were found for test-retest reliability, criterion validity, and construct validity. REVIEW REGISTRATION: PROSPERO (CRD42022347744).

Reference values for estimated VO2max by two submaximal cycle tests: the Åstrand-test and the Ekblom-Bak test.

AIMS: Submaximal tests estimating VO2max have inherent biases; hence, using VO2max estimations from the same test is essential for reducing this bias. This study aimed to establish sex- and age-specific reference values for estimated VO2max using the Åstrand-test (Å-test) and the Ekblom-Bak test (EB-test). We also assessed the effects of age, exercise level, and BMI on VO2max estimations. METHODS: We included men and women (20-69 years) from the Swedish working population participating in Health Profile Assessments between 2010 and 2020. Excluding those on heart rate-affecting medicines and smokers, n = 263,374 for the Å-test and n = 95,043 for the EB-test were included. VO2max reference values were based on percentiles 10, 25, 40, 60, 75, and 90 for both sexes across 5-year age groups. RESULTS: Estimated absolute and relative VO2max were for men 3.11 L/min and 36.9 mL/min/kg using the Å-test, and 3.58 L/min and 42.4 mL/min/kg using the EB-test. For women, estimated absolute and relative VO2max were 2.48 L/min and 36.6 mL/min/kg using the Å-test, and 2.41 L/min and 35.5 mL/min/kg using the EB-test. Higher age (negative), higher exercise level (positive), and higher BMI (negative) were associated with estimated VO2max using both tests. However, explained variance by exercise on estimated VO2max was low, 10% for the Å-test and 8% for the EB-test, and moderate for BMI, 23% and 29%. CONCLUSION: We present reference values for estimated VO2max from two submaximal cycle tests. Age, exercise, and BMI influenced estimated VO2max. These references can be valuable in clinical evaluations using the same submaximal tests.

Predicting Maximum Oxygen Uptake from Non-Exercise and Submaximal Exercise Tests in Paraplegic Men with Spinal Cord Injury.

This study aimed to develop prediction equations for maximum oxygen uptake (VO2max) based on non-exercise (anthropometric) and submaximal exercise (anthropometric and physiological) variables in paraplegic men with a spinal cord injury. All participants were tested on an arm ergometer using a maximal graded exercise test. Anthropometric variables such as age, height, weight, body fat, body mass index, body fat percentage, and arm muscle mass and physiological variables such as VO2, VCO2, and heart rate at 3 and 6 min of graded exercise tests were included in the multiple linear regression analysis. The prediction equations revealed the following. Regarding non-exercise variables, VO2max was correlated with age and weight (equation R = 0.771, R2 = 0.595, SEE= 3.187). Regarding submaximal variables, VO2max was correlated with weight and VO2 and VCO2 at 6 min (equation R = 0.892, R2 = 0.796, SEE = 2.309). In conclusion, our prediction equations can be used as a cardiopulmonary function evaluation tool to estimate VO2max simply and conveniently using the anthropometric and physiological characteristics of paraplegic men with spinal cord injuries.

Validation of a Modified Submaximal Balke Protocol to Assess Cardiorespiratory Fitness in Individuals at High Risk of or With Chronic Health Conditions-A Pilot Study.

Objectives: This study aims to validate a submaximal treadmill walking test for estimation of maximal oxygen consumption (VO2max) in individuals at high risk of or with chronic health conditions. Method: Eighteen participants (age 62 ± 16 years; VO2max 31.2 ± 5.9 ml kg-1 min-1) at high risk of getting or with established chronic diseases performed two valid modified Balke treadmill walking protocols, one submaximal protocol, and one maximal protocol. Test duration, heart rate (HR), and rate of perceived exertion (RPE) were measured during both tests. VO2max was measured during the maximal test. VO2max was estimated from the submaximal test by multiple regression using time to RPE ≥ 17, gender, age, and body mass as independent variables. Model fit was reported as explained variance (R 2) and standard error of the estimate (SEE). Results: The model fit for estimation of VO2max from time to RPE ≥ 17 at the submaximal test, body mass, age, and gender was R 2 = 0.78 (SEE = 3.1 ml kg-1 min-1, p ≤ 0.001). Including heart rate measurement did not improve the model fit. Conclusions: The submaximal walking test is feasible and valid for assessing cardiorespiratory fitness in individuals with high risk of or chronic health conditions.

Comparison of the Ekblom-Bak Submaximal Test to a Maximal Test in a Cohort of Healthy Younger and Older Adults in the United States.

Cardiorespiratory fitness (CRF) is routinely investigated in diverse populations, including in older adults of varying physical activity levels. Commonly performed maximal exercise testing protocols might be contraindicated and/or inadequate for older individuals who have physical or cognitive impairment. Moreover, early termination of an attempted maximal exercise test could result in underestimation of CRF in this population. The goal of the current study was to compare CRF estimates using the Ekblom-Bak (EB) submaximal exercise test - previously validated in a cohort of Scandinavian adults - versus a subsequent maximal exercise test in a diverse, Midwestern United States cohort. Fifteen generally healthy individuals were included in this study who were either "Young" (25-34 years old) or "Older" (55-75 years old) as well as either sedentary or highly active. Participants completed the EB submaximal exercise test, followed immediately by a maximal exercise test. We found that all 15 individuals were able to successfully perform the EB submaximal testing method. Across the wide range of volumes of maximal oxygen consumption (VO2max; 12-52 ml/kg/min), the EB submaximal estimates of VO2max correlated highly with the maximal test based values (Pearson's r = 0.98), but with a small bias (6 ml/kg/min, 95% limits of agreement -1.06 and -11.29). Our results suggest that the EB submaximal testing method may be useful in identifying wide differences in CRF among a diverse cohort of older adults in the United States, but larger studies will be needed to determine the degree of its accuracy and precision in identifying smaller differences.

Criterion validity of the Ekblom-Bak and the Åstrand submaximal test in an elderly population.

PURPOSE: The aim of this study was to validate the submaximal Ekblom-Bak test (EB-test) and the Åstrand test (Å-test) for an elderly population. METHODS: Participants (n = 104), aged 65-75 years, completed a submaximal aerobic test on a cycle ergometer followed by an individually adjusted indirect calorimetry VO2max test on a treadmill. The HR from the submaximal test was used to estimate VO2max using both the EB-test and Å-test equations. RESULTS: The correlation between measured and estimated VO2max using the EB method and Å method in women was r = 0.64 and r = 0.58, respectively and in men r = 0.44 and r = 0.44, respectively. In women, the mean difference between estimated and measured VO2max was - 0.02 L min-1 (95% CI - 0.08 to 0.04) for the EB method and - 0.12 L min-1 (95% CI - 0.22 to - 0.02) for the Å method. Corresponding values for men were 0.05 L min-1 (95% CI - 0.04 to 0.14) and - 0.28 L min-1 (95% CI - 0.42 to - 0.14), respectively. However, the EB method was found to overestimate VO2max in men with low fitness and the Å method was found to underestimate VO2max in both women and men. For women, the coefficient of variance was 11.1%, when using the EB method and 19.8% when using the Å method. Corresponding values for men were 11.6% and 18.9%, respectively. CONCLUSION: The submaximal EB-test is valid for estimating VO2max in elderly women, but not in all elderly men. The Å-test is not valid for estimating VO2max in the elderly.

Prediction of upper extremity peak oxygen consumption from heart rate during submaximal arm cycling in young and middle-aged adults.

Based on the strong linear relationship between heart rate (HR) and oxygen consumption, the Åstrand-Ryhming cycle ergometer test (Astrand and Ryhming in J Appl Physiol 7:218-221, 1954) is a widely used submaximal test to predict whole body maximal oxygen consumption ([Formula: see text]). However, a similar test predicting peak oxygen consumption ([Formula: see text]) in the upper extremities is not established, and may be very useful for individuals unable to use their lower extremities or/and if separation of upper extremity aerobic capacity is sought after. Thus, the aim of the current study was to develop a submaximal test predicting [Formula: see text] in arm-cycling. Forty-nine healthy volunteers (25 women: 38 ± 13 years; 24 men: 39 ± 12 years) tested arm-cycle [Formula: see text] on a protocol with 4-min, 21-W increments to exhaustion. The data were contrasted to treadmill [Formula: see text] values. Arm-cycle [Formula: see text] was 66 ± 8% of [Formula: see text] (r = 0.92, p < 0.001; women: 1.9 ± 0.4 L min-1; men: 3.0 ± 0.7 L min-1). Arm-cycle HR and [Formula: see text] exhibited correlations of r = 0.79 and r = 0.78 for women and men, respectively, while corresponding correlations between work rate and [Formula: see text] were r = 0.95 (women) and r = 0.89 (men) (all p < 0.001). Arm-cycle [Formula: see text] prediction revealed a standard error of estimate (SEE) of 11.2% (women) and 10.2% (men), and was primarily due to individual arm-cycle maximal HR (women: 173 ± 13 beats min-1; men: 174 ± 10 beats min-1; correction factor: 5-7%). In conclusion, from a single 4-min stage of submaximal arm cycling, [Formula: see text] can be predicted with a SEE of 10-11%. The arm-cycle test may have important value for individuals who rely on arms in sports and occupations, and for patients with lower extremity disabilities.

A 6-minute sub-maximal run test to predict VO2 max.

Maximal oxygen uptake ([Formula: see text] max) is a key indicator to assess health as well as sports performance. Currently, maximal exercise testing is the most accurate measure of maximal aerobic power, since submaximal approaches are still imprecise. In this paper, we propose a new method to predict [Formula: see text] max from a submaximal, low intensity, test in sports men and women. 182 males and 108 females from the High Performance Center of Pontevedra (Spain), aged 10-46 years old, with a [Formula: see text] max between 30.1 and 81.2 mL·min-1·kg-1, completed a maximal incremental test to volitional exhaustion. The test began at a speed of 6 km·h-1 and increased by 0.25 km·h-1 every 15 seconds. Using the data gathered during the first 6 minutes of the test, two different regression models were adjusted using functional data analysis and a traditional linear regression model with scalar covariates. The functional regression model obtained the best results, adjusted r2 = 0.845 and RMSE = 2.8 mL·min-1·kg-1, but the linear regression model also obtained a good fit, adjusted r2 = 0.798 and RMSE = 3.5 mL·min-1·kg-1. Both methods are more accurate than classical submaximal tests, although oxygen consumption needs to be measured during the test.

Prueba de escalón de Mcardle: una ecuación para estimar el Vo2 máx. en estudiantes de educación física / Mcardle step test: an equation for estimating the VO2 max. in physical education students

El objetivo de esta investigación es obtener una ecuación para determinar VO2 máx. a través de una prueba submáxima utilizando la frecuencia cardíaca de recuperación (FCr). Se diseñó en un estudio descriptivo correlacional dentro de un marco cuantitativo y se evaluó a 18 sujetos, 9 damas y 9 varones, de primero a cuarto año estudiantes de educación física con un muestreo de tipo intencional. Se midió la FCr en la prueba submáxima en escalón de McArdle, utilizando el monitor de FC marca Polar mo-delo V800 (Finlandia), y el consumo máximo de oxígeno (VO2 máx.) en el test de esfuerzo máximo de Bruce con el analizador de gases marca COSMED, modelo Fitmate PRO (Italia). En los resultados, la correlación (coeficiente de Pearson) que se obtuvo fue de r = ­0.84 (p<0.001) la cual se encuentra en una categoría considerable, obteniendo la ecuación y = ­0.4132 x + 110.68 con un error de estimación estándar (EEE) de 5.8 ml.kg.min­1.

The main aim of this research is to obtain an equation to determine the VO2 max through a submaximal test using heart rate recovery (HRr). A correlational descriptive study was designed within a quantitati-ve framework, where 18 subjects, all physical education college students, from freshman to senior year, were evaluated (9 females and 9 males), using diversity sampling (intentional). The HRr was measured in the McArdle submaximal step using the HR monitor, Polar V800 model (Finland), and the VO2 max. in the Bruce maximum effort test was measured with the gas analyzer COSMED model Fitmate PRO (Italy). In the results, the correlation (Pearson coefficient) obtained was r = −0.84 (p<0.001) which is within the considerable category, obtaining the equation y = 0.4132 x + 110.68 with a standard error of estimation (SEE) of 5.8 ml.kg.min−1.

Validity of the revised Ekblom Bak cycle ergometer test in adults.

PURPOSE: To further develop the Ekblom Bak-test prediction equation for estimation of VO2max from submaximal cycle ergometry. METHODS: The model group (117 men and 100 women, aged 48.3 ± 15.7 and 46.1 ± 16.8 years, VO2max 46.6 ± 11.1 and 40.4 ± 9.6 mL kg(-1) min(-1), respectively) and the cross-validation group (60 men and 55 women, aged 40.6 ± 17.1 and 41.6 ± 16.7 years, VO2max 49.0 ± 12.1 and 43.2 ± 8.9 mL min(-1) kg(-1), respectively) performed 4 min of cycling on a standard work rate (30 W) directly followed by 4 min on a higher work rate. Heart rate (HR) at each work rate was recorded. Thereafter, participants completed a graded maximal treadmill test for direct measurement of oxygen uptake. The new prediction equation was cross-validated and accuracy compared with the original Ekblom Bak equation as well as by the Åstrand test method. RESULTS: The final sex-specific regression models included age, change in HR per-unit change in power (ΔHR/ΔPO), the difference in work rates (ΔPO), and HR at standard work rate as independent variables. The adjusted R (2) for the final models were 0.86 in men and 0.83 in women. The coefficient of variation (CV) was 8.7 % and SEE 0.28 L min(-1). The corresponding CV and SEE values for the EB-test2012 and the Åstrand tests were 10.9 and 18.1 % and 0.35 and 0.48 L min(-1), respectively. CONCLUSION: The new EB-test prediction equation provides an easy administered and valid estimation of VO2max for a wide variety of ages (20-86 years) and fitness levels (19-76 mL kg(-1) min(-1)).

Prediction of Maximal Oxygen Consumption from Rating of Perceived Exertion (RPE) using a Modified Total-body Recumbent Stepper.

Exercise training is crucial to improve cardiovascular health and quality of life in people with spinal cord injuries (SCI). A key limitation is the lack of validated submaximal tests to evaluate and predict cardiovascular fitness in this population. The purpose of this study was to validate a submaximal test to predict maximal oxygen consumption for individuals with SCI. Ten able-bodied participants and two individuals with SCI completed a rating of perceived exertion (RPE)-based submaximal oxygen consumption test and a graded maximal oxygen consumption test on a NuStep T4 recumbent stepper. Prediction of VO2max from an RPE-based protocol is feasible and can produce reliable predicted VO2max values in the able bodied population. This study is a proof of concept to the implementation of a submaximal test protocol using a total body recumbent stepper to predict VO2max in able-bodied individuals. Additionally, this study shows evidence of feasibility of performing this test in SCI individuals.