Are fixed-rate step tests medically safe to assess physical fitness?

Jessa Hospital/Heart Centre Hasselt, Rehabilitation and Health Centre, Stadsomvaart 11, Hasselt, Belgium.
Arbeitsphysiologie (Impact Factor: 2.19). 03/2011; 111(10):2593-9. DOI: 10.1007/s00421-011-1886-3
Source: PubMed


Maximal oxygen uptake (VO(2max)) can be predicted by fixed-rate step tests. However, it remains to be analyzed as to what exercise intensities are reached during such tests to address medical safety. In this study, we compared the physiological response to a standardized fixed-rate step test with maximal cardiopulmonary exercise testing (CPET). One hundred and thirteen healthy adults executed a maximal CPET on bike, followed by a standardized fixed-rate step test 1 week later. During these tests, heart rate (HR) and VO(2) were monitored continuously. From the maximal CPET, the ventilatory threshold (VT) was calculated. Next, the physiological response between maximal CPET and step testing was compared. The step test intensity was 85 ± 24% CPET VO(2max) and 88 ± 11% CPET HR(max) (VO(2max) and HR(max) were significantly different between CPET and step testing; p < 0.01). In 41% of the subjects, step test exercise intensities >95% CPET VO(2max) were noted. A greater step testing exercise intensity (%CPET VO(2max)) was independently related to higher body mass index, and lower body height, exercise capacity (p < 0.05). Standardized fixed-rate step tests elicit vigorous exercise intensities, especially in small, obese, and/or physically deconditioned subjects. Medical supervision might therefore be required during these tests.

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Available from: Neree Claes, Oct 04, 2015
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    • "This limitation could be partially overcome by a low speed adopted as a " baseline " for the ST. In the incremental test, the adoption of a step of fixed height also imposes certain limitations, since the ideal would be to adjust the height of the step to the subjects' body height (Hansen et al., 2011). Without this, the result could be very large differences in exercise time, because the load theoretically applied on ST depends on the height of the step (see Eq. (2)). "
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    ABSTRACT: To date little is known about the reliability of peak oxygen consumption (V˙O2PEAK) in incremental metronome paced step tests (IST) and the reliability of on-kinetics V˙O2 has never been studied. We aimed to study the reliability of both tests. Eleven healthy subjects performed two IST until exhaustion. On two different days two duplicate four minute constant metronome paced step tests (CST) were performed. V˙O2PEAK, mean response time (MRT) and phase II time constant (τ) were tested for reproducibility using the paired t-tests, in addition to the limits of agreement (LOA) and within subject coefficient of variation (COV). With a 95% LOA of 0.38 to 0.26 L.min(-1), -8.7 to 9.1s and -9.9 to 10.5s they exhibit a COV of 3%, 4.5% and 6.9% for V˙O2PEAK, MRT and τ respectively. ST are sufficiently reliable for maximal and submaximal aerobic power assessments in healthy subjects and new studies of oxygen uptake kinetics in selected patient groups are warranted. Copyright © 2014 Elsevier B.V. All rights reserved.
    Respiratory Physiology & Neurobiology 12/2014; 207. DOI:10.1016/j.resp.2014.12.001 · 1.97 Impact Factor
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    • "In either case, this assessment allows a more accurate exercise prescription when looking for significant benefits with regard to fitness and health (Anton et al., 2011). Furthermore VO2max is a useful parameter to assess the effects of physical training on the cardiorespiratory system (Hansen et al., 2011). Such tests are sometimes based on the linear relationship between the heart rate and oxygen uptake (Wicks et al., 2011), typically during submaximal steady-state exercise tests. "
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    ABSTRACT: Laboratory ergometers have high costs, becoming inaccessible for most of the population, hence, it is imperative to develop affordable devices making evaluations like cardiorespiratory fitness feasible and easier. The objective of this study was to develop and validate an Automated Step Ergometer (ASE), adjusted according to the height of the subject, for predicting VO2max through a progressive test. The development process was comprised by three steps, the theoretical part, the prototype assembly and further validation. The ASE consists in an elevating platform that makes the step at a higher or lower level as required for testing. The ASE validation was obtained by comparing the values of predicted VO2max (equation) and direct gas analysis on the prototype and on a, treadmill. For the validation process 167 subjects with average age of 31.24 ± 14.38 years, of both genders and different degrees of cardiorespiratory fitness, were randomized and divided by gender and training condition, into untrained (n=106), active (n=24) and trained (n=37) subjects. Each participant performed a progressive test on which the ASE started at the same height (20 cm) for all. Then, according to the subject's height, it varied to a maximum of 45 cm. Time in each stage and rhythm was chosen in accordance with training condition from lowest to highest (60-180 s; 116-160 bpm, respectively). Data was compared with the student's t test and ANOVA; correlations were tested with Pearson's r. The value of α was set at 0.05. No differences were found between the predicted VO2max and the direct gas analysis VO2max, nor between the ASE and treadmill VO2max (p= 0.365) with high correlation between ergometers (r= 0.974). The values for repeatability, reproducibility, and reliability of male and female groups measures were, respectively, 4.08 and 5.02; 0.50 and 1.11; 4.11 and 5.15. The values of internal consistency (Cronbach's alpha) among measures were all >0.90. It was verified that the ASE prototype was appropriate for a step test, provided valid measures of VO2max and could therefore, be used as an ergometer to measure cardiorespiratory fitness.
    Journal of Human Kinetics 09/2014; 43(1):113-24. DOI:10.2478/hukin-2014-0096 · 1.03 Impact Factor
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    • "Smoking was questioned using a short questionnaire from a national health questionnaire [18]. Physical fitness was tested with a step test, stepping up and down a platform (90 beats steps per minute) during 5 minutes [19]. Heart rate was recorded 1, 2 and 3 minutes after completing the step test in sitting position. "
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    ABSTRACT: Background Cardiovascular disease is a major cause of mortality and morbidity and its prevalence is set to increase. While the benefits of medical and lifestyle interventions are established, the effectiveness of interventions which seek to improve the way preventive care is delivered in general practice is less so. The aim was to study and to compare the effectiveness of 2 intervention programmes for reducing cardiovascular risk factors within general practice. Methods A randomised controlled trial was conducted in Belgium between 2007-2010 with 314 highly educated and mainly healthy professionals allocated to a medical (MP) or a medical + lifestyle (MLP) programme. The MP consisted of medical assessments (screening and follow-up) and the MLP added a tailored lifestyle change programme (web-based and individual coaching) to the MP. Primary outcomes were total cholesterol, blood pressure, and body mass index (BMI). The secondary outcomes were smoking status, fitness-score, and total cardiovascular risk. Results The mean age was 41 years, 95 (32%) participants were female, 7 had a personal cardiovascular event in their medical history and 3 had diabetes. There were no significant differences found between MP and MLP in primary or secondary outcomes. In both study conditions decreases of cholesterol, systolic blood pressure, and diastolic blood pressure were found. Unfavourable increases were found for BMI (p < .05). A significant decrease of the overall cardiovascular risk was reported (p < .001). Conclusions Both interventions are effective in reducing cardiovascular risk. In our population the combined medical and lifestyle programme was not superior to the medical programme.
    BMC Cardiovascular Disorders 06/2013; 13(1):38. DOI:10.1186/1471-2261-13-38 · 1.88 Impact Factor
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