Does the incremental shuttle walk test require maximal effort in young obese women?

Reproducibility, validity, and reliability of the incremental step test for subjects with moderate to severe asthma

OBJECTIVE

We investigated the measurement properties of the incremental step test in subjects with moderate to severe asthma.

METHODS

Subjects with moderate to severe persistent asthma were recruited from a tertiary university hospital specializing in treating severe asthma. All subjects performed one cardiopulmonary exercise test (CPET) and two incremental step tests (IST) in random sequences. Pulmonary gas exchange was measured during all exercise tests. The measurement properties investigated were reliability by intraclass correlation coefficient (ICC), measurement error by the standard error of measurement and minimum detectable difference, construct validity by Pearson's correlation, and interpretability by the ceiling and floor effects.

RESULTS

Fifty subjects (38 females, mean [SD], age 43.7 [11.6] yr, % FEV1 70 [14.3], BMI 28.5 [5.3] kg/m2) completed the study. The peak oxygen uptake (peak VO2) for the CPET was 27.6 [±6.8] ml/kg/min, for the first IST was 22.3 [±5.3] ml/kg/min and for the second IST was 23.3 [±5.3] ml/kg/min. The IST presented excellent reliability (ICC=0.93, CI95% 0.88-0.96), very good measurement error (2.5%), and construct validity for peak VO2 measurement compared to the CPET (r = 0.85; p < 0.001) to assess exercise capacity in subjects with moderate to severe asthma, with appropriate ceiling (10%) and floor (0%) effects.

CONCLUSION

The IST presented excellent reliability and very good measurement error and validity to assess exercise capacity in subjects with moderate to severe asthma, without ceiling or floor effects.

Cross-Validation of Predictive Equation for Cardiorespiratory Fitness by Modified Shuttle Walk Test in Adults with Schizophrenia: A Secondary Analysis of the CORTEX-SP Study

Cardiorespiratory fitness (CRF) can be direct or estimated from different field tests. The Modified Shuttle Walk Test (MSWT) is suitable for all levels of function, allowing a peak response to be elicited. Therefore, we aimed (1) to validate the equation presented in the original study by Singh et al. for evaluating the relationship between MSWT with peak oxygen uptake (VO_2peak) in adults with schizophrenia (SZ), (2) to develop a new equation for the MSWT to predict VO_2peak, and (3) to validate the new equation. Participants (N = 144, 41.3 ± 10.2 years old) with SZ performed a direct measurement of VO_2peak through a cardiopulmonary exercise test and the MSWT. A new equation incorporating resting heart rate, body mass index, and distance from MSWT (R² = 0.617; adjusted R² = 0.60; p < 0.001) performs better than the Singh et al. equation (R² = 0.57; adjusted R² = 0.57; p < 0.001) to estimate VO_2peak for the studied population. The posteriori cross-validation method confirmed the model’s stability (R² = 0.617 vs. 0.626). The findings of the current study support the validity of the new regression equation incorporating resting heart rate, body mass index, and distance from MSWT to predict VO_2peak for assessment of CRF in people with SZ.

Validity of the Incremental Shuttle Walk Test to Assess Exercise Safety When Initiating Cardiac Rehabilitation in Low-Resource Settings

PURPOSE

To evaluate the validity of the Incremental Shuttle Walk Test (ISWT) for determining risk stratification in cardiac rehabilitation (CR).

METHODS

This is a cross-sectional study at a major CR center in a middle-income country. Clinically stable adult cardiac patients underwent an ISWT and an exercise test (ET), wore a pedometer for 7 d, and completed the Godin-Shepherd Leisure-Time Physical Activity Questionnaire. Metabolic equivalents of task (METs) achieved on the ISWT were calculated.

RESULTS

One hundred fifteen patients were evaluated. The mean ± standard deviation distance on the ISWT was 372.70 ± 128.52 m and METs were 5.03 ± 0.62. The correlation of ISWT distance with ET METs (7.57 ± 2.57), steps/d (4556.71 ± 3280.88), and self-reported exercise (13.08 ± 15.19) was rs = 0.61 (P < .001), rs = 0.37 (P < .001), and rs = 0.20 (P = .031), respectively. Distance on the ISWT accurately predicted METs from the ET (area under the receiver operating characteristic curve = 0.774). The ability to walk ≥410 m on the ISWT predicted, with a specificity of 81.5% and a sensitivity of 65.6%, a functional capacity of ≥7 METs on ET.

CONCLUSION

The ISWT is an alternative way to evaluate functional capacity in CR and can contribute to the process of identifying patients at low risk for a cardiac event during exercise at moderate intensity.

Validation of the two-minute step test in obese with comorbibities and morbidly obese patients

Cardiopulmonary fitness assessment is a valuable resource to obtain quantitative indicators of an individual's physical performance. The cardiopulmonary exercise test (CPX), considered the gold standard test for this evaluation, is costly and difficult to be accessed by the general population. In order to make this evaluation more accessible, and to better reflect the performance of daily life activities, alternative tests were proposed. Morbidly obese patients present limitations that impair physical performance assessment and could benefit from a test of shorter duration, provided it is validated. This observational study aimed to validate the two-minute step test (2MST) as a tool to evaluate functional capacity (FC) in obese with comorbidities and morbidly obese patients, compared the 2MST with CPX as a measure of physical performance, and developed a predictive equation to estimate peak oxygen uptake (VO₂) in the 2MST. The CPX and the 2MST were performed and metabolic and ventilatory parameters were recorded in 31 obese individuals (BMI>35 kg/m²). Pearson correlation and multiple linear regression analyses were performed to evaluate the peak VO₂ best predictors. Bland-Altman analysis was performed to assess the agreement between the two methods. Peak VO₂ measured by CPX and 2MST showed a strong correlation (r=0.70, P<0.001) and there was a moderate correlation between peak VO₂ of the 2MST and the number of up-and-down step cycles (UDS) (r=0.55; P=0.01). The reference equation obtained was: VO₂ (mL·kg^-1·min^-1) = 13.341 + 0.138 × total UDS – (0.183 × BMI), with an estimated standard error of 1.3 mL·kg^-1·min^-1. The 2MST is a viable, practical, and easily accessible test for FC. UDS and BMI can predict peak VO₂ satisfactorily.

Cardiorespiratory fitness assessment and prediction of peak oxygen consumption by Incremental Shuttle Walking Test in healthy women

INTRODUCTION

Preliminary studies have showed that the Incremental Shuttle Walking Test (ISWT) is a maximal test, however comparison between ISWT with the cardiopulmonary exercise test (CEPT) has not yet performed in the healthy woman population. Furthermore, there is no regression equation available in the current literature to predict oxygen peak consumption (VO2 peak). Thus, this study aimed to compare the ISWT with CEPT and to develop an equation to predict peak oxygen uptake (VO2 peak) in healthy women participants.

METHODS

First, the VO2 peak, respiratory exchange ratio (R peak), heart rate max (HR max) and percentage of predicted HR max (% predicted HR max) were evaluated in the CEPT and ISWT (n = 40). Then, an equation was developed to predict the VO2 peak (n = 54) and its validation was performed (n = 20).

RESULTS

There were no significant differences between the ISWT and CEPT of VO2 peak, HR max and % predicted HR max values (P>0.05), except for R peak measure in the ISWT (1.22 ± 0.13) and CEPT (1.18 ± 0.1) (P = 0.022). Therefore, both tests showed a moderate positive correlation of VO2 peak (r = 0.51; P = 0.0007), HR max (r = 0.65; P<0.0001) and R peak (r = 0.55; P = 0.0002) and the Bland-Altman analysis showed agreement of VO2 peak (bias = -0.14). The distance walked on ISWT and age explained 36.3% (R2 Adjusted = 0.363) of the variance in VO2 peak. The equation developed was VO2 peak (predicted) = 19.793 + (0.02 x distance walked)-(0.236 x age). There was no statistically significant difference between the VO2 peak measured directly and the predicted, and the Bland-Altman analysis showed agreement (bias = 1.5 ml/kg/min).

CONCLUSION

ISWT is a maximal test showing similar results compared to the CEPT, and the predicted equation was valid and applicable for VO2 peak assessing in young adult healthy women.