A new equation based on the 6-min walking test to predict VO2peak in women with obesity

Objective: The 6-min walking test (6?MWT) is commonly used to assess obese patients’ aerobic fitness, but it has rarely been compared with a direct measurement of maximal aerobic capacities (VO_2max or VO_2peak) in obese adults. The aim of this study was to investigate the relationship between the distance covered during a 6?MWT with objectively measured VO_2peak and to propose a new equation to predict VO_2peak from this walking test in obese patients.

Methods: One hundred and thirty-seven obese patients (45.6?±?12.5?years) admitted to our hospital for a multidisciplinary rehabilitation program were enrolled. After assessment of their body composition, the participants were asked to perform a 6?MWT and their maximal aerobic capacities (VO_2peak) were measured.

Result: There is a significant linear relation between VO_2peak and the distance covered during the 6?MWT (p?r?=?0.349). The determinant of VO_2peak was body mass index, waist-to-hip ratio, fat free mass, leading to the follow prediction equation VO_2peak such as VO_2peak (l/min)?=?(body mass index ×0.0150065)???(waist-to-hip-ratio?×?0.8595088)?+?(fat-free-mass?×?0.0295478)?+?(6-min walk test?×0.0020672)???0.5853372.

Conclusion: The 6-min walk test is a reliable method to reflect obese women’s aerobic capacities and the distance covered can be used to accurately estimate VO_2peak according to our newly proposed equation.

• Implication for rehabilitation

• Obesity is a worldwide disease and physical capacity evaluation is a key point for rehabilitation.

• The six minutes’ walk test is commonly used in obese people to assess aerobic fitness.

• This study proposes a new equation using 6?MWT performance to estimate VO_2peak.

     

Test–retest reliability,validation, and “minimal detectable change” scores for frequently reported tests of objective physical function in patients with non-dialysis chronic kidney disease

Physical function is an important outcome in chronic kidney disease (CKD). We aimed to establish the reliability, validity, and the “minimal detectable change” (MDC) of several common tests used in renal rehabilitation and research. In a repeated measures design, 41 patients with CKD not requiring dialysis (stage 3b to 5) were assessed at an interval of 6 weeks. The tests were the incremental shuttle walk test (ISWT), “sit-to-stand” (STS) test, estimated 1 repetition maximum for quadriceps strength (e1RM), and VO_2peak by cardiopulmonary exercise testing (CPET). Reliability was assessed using intraclass correlation coefficient and Bland–Altman analysis, and absolute reliability by standard error of measurement and MDC. The ISWT, STS-60, e1RM, and CPET had “good” to “excellent” reliability (0.973, 0.927, 0.927, and 0.866), respectively. STS-5 reliability was poor (0.676). The MDC is ISWT, 20 m; STS-5, 7.5 s; STS-60, 4 reps; e1RM, 6.4 kg; VO_2peak, 2.8 ml/kg/min. There was strong correlation between the ISWT and VO_2peak (r = 0.73 and 0.74). While there was poor correlation between the STS-5 and e1RM (r = 0.14 and 0.47), better correlation was seen between STS-5 and ISWT (r = 0.55 and 0.74). In conclusion, the ISWT, STS-60, e1RM, and CPET are reliable tests of function in CKD. The ISWT is a valid means of exercise capacity. The MDC can help researchers and rehabilitation professionals interpret changes following an intervention.     

Reliability and a correlational analysis of the 6MWT,ten-meter walk test,thirty second sit to stand,and the linear analog scale of function in patients with head and neck cancer

Objective: The purpose of this study was to establish the test–retest reliability of and relationships between various measures of physical function in a cohort of individuals in the early treatment stages for head and neck cancer (HNC). Methods: The Six-Minute Walk Test (6MWT), 10-Meter Walk Test (10MWT), 30-Second Sit to Stand (30STS), and Linear Analog Scale of Function (LASF) were administered to 42 participants with a diagnosis of HNC. Test–retest reliability and correlations between the measures are reported. Results: The 6MWT, 10MWT, 30STS, and LASF demonstrate excellent test–retest reliability (ICC = 0.901–0.960). The 6MWT exhibits a moderate to good relationship with the 10MWT (r = 0.684, p < 0.001), whereas the relationship between the 30STS and the 6MWT (r = 0.407, p = 0.007) and 10MWT (r = 0.322, p = 0.038) is fair. The LASF does not correlate significantly with the 6MWT, 10MWT, or 30STS. Conclusions: The 6MWT, 10MWT, 30STS, and LASF are reliable measurement instruments for patients treated for HNC. The 6MWT, 10MWT, and 30STS are significantly correlated suggesting they may measure subconstructs of physical function. The LASF does not correlate significantly with the 6MWT, 10MWT and 30STS in this sample.     

Oxygen uptake efficiency slope: A submaximal test evaluation tool that provides cardiopulmonary reserve data in individuals with Parkinson's disease

BackgroundOxygen uptake efficiency slope (OUES) is a method for investigating cardiorespiratory fitness and is proposed as an alternative to overcome the limitations of traditional measures such as peak oxygen consumption (VO_2peak) for patients who do not achieve a maximum response, such as in Parkinson's disease (PD).ObjectiveTo assess the performance of individuals with PD during the six-minute walk test (6MWT) using the OUES.MethodsThis is an observational cross-sectional study including 12 individuals with PD and 12 healthy controls. Participants performed the 6MWT along with an analysis of exhaled gas kinetics. The OUES was determined from the last 16 s of the walk test. Multiple linear regression analyses were computed to explore associations between the independent (OUES) and the dependent variables (VO_2peak) controlled by group.ResultsThe OUES was associated to VO_2peak on the 6MWT (β=0.24, p<0.01) in individuals with PD. The PD group had low performance on the 6MWT with a shorter distance walked (mean difference: -113.1 m; 95% CI: -203.2, -59.1) and worse cardiopulmonary condition with lower OUES values (mean difference: -0.52 [l/minO₂]/[l/minVE]; 95% CI: -0.83, -0.21) found in this same group.ConclusionsOur results suggest that OUES is related to VO_2peak during the 6MWT, and therefore it could be used as a submaximal test evaluation tool which provides cardiopulmonary reserve data in individuals with PD.     

The Shuttle Walk Test: A New Approach to Functional Walking Capacity Measurements for Patients After Stroke?

van Bloemendaal M, Kokkeler AM, van de Port IG. The shuttle walk test: a new approach to functional walking capacity measurements for patients after stroke?ObjectiveTo determine the construct validity, test-retest reliability, and measurement error of the shuttle walk test (SWT) for patients after stroke.DesignClinimetric study.SettingThree rehabilitation centers in the Netherlands.ParticipantsA sample of patients after stroke (N=75; mean age ± SD, 58.8±9.8y) who are capable of walking without physical assistance. Patients were excluded if they had sustained a subarachnoid hemorrhage or a stroke in the cerebellum or brainstem, or had any other conditions that limited their walking capacity more than the current stroke, or had sensory aphasia.InterventionsNot applicable.Main Outcome MeasuresConstruct validity (6-minute walk test [6MWT]) and test-retest reliability of the SWT were assessed. Measurement error was determined with the standard error of measurement (SEM), limits of agreement, and smallest detectable differences (SDDs).ResultsConstruct validity was confirmed by high significant correlations (r_p≥.65, P<.01) between the SWT and 6MWT. Difference scores were significantly higher in favor of the SWT for high-speed walkers (≥0.8m/s). In the small group (n=12) of low-speed walkers (<0.8m/s), no significant correlations and differences between both tests were found except for walking distance in favor of the 6MWT. Test-retest reliability was good (intraclass correlation coefficient model 2,1 [ICC_2,1]=.961 [.936–.977]). SEM was 6.0%, and the SDDs for individual and group were 302.0m (37%) and 38.7m (5%), respectively.ConclusionsThe SWT is a valid and reliable measure and therefore a feasible instrument to determine functional walking capacity of patients after stroke, especially in high-speed walkers.     

Cardiorespiratory and metabolic demand of the 6-minute pegboard and ring test in healthy young adults

ObjectiveTo determine the cardiorespiratory and metabolic demand of the Six-Minute Pegboard and Ring Test (6PBRT) in healthy young adults and its association with maximal arm cycle ergometer test (arm CET).MethodsVolunteers were randomized to performed the 6PBRT test or arm CET. The second test was performed after 48 h. Oxygen consumption (VO₂), heart rate (HR), dyspnea and upper limb fatigue were assessed during the tests. Demographic data, body composition, level of physical activity, arm strength and endurance were also evaluated.ResultsDuring 6PBRT, VO₂ values increased from 5.8 to 11.1 mL kg⁻¹.min⁻¹ (p < 0.001). VO_2peak, HR _Mean and HR_max at 6PBRT were 47.2% and close to 65% respectively of those achieved during the arm CET. There was a positive correlation between the score on 6PBRT and VO_2mean and VO_2peak achieved at arm CET (r = 0.268; p = 0.003 and r = 0.247; p = 0.046 respectively). No correlation was found between the HR_mean, HR_peak, level of physical activity or strength with 6PBRT (p > 0.05). Handgrip endurance had a positive correlation with score on 6PBRT (r = 0.237; p = 0.054). Body Mass Index, body fat and fat mass were negatively correlated with the score on 6PBRT (r = 0.301; p = 0.014, 0.329; p = 0.007 and r = 0.427; p = 0.001).ConclusionsThe 6PBRT test showed a moderate cardiorespiratory and metabolic demand in healthy individuals in comparison of arm CET. BMI, body fat and fat mass correlated with the score on 6PBRT.     

Muscle strength,aerobic capacity and physical activity in independent ambulating children with lumbosacral spina bifida

Purpose. This cross-sectional study investigates deficits and associations in muscle strength, 6-minute walking distance (6MWD), aerobic capacity (VO_2peak), and physical activity (PA) in independent ambulatory children with lumbosacral spina bifida.

Method. Twenty-tree children participated (13 boys, 10 girls). Mean age (SD): 10.4 (±3.1) years. Muscle strength (manual muscle testing and hand-held dynamometry), 6MWD, VO_2peak (maximal exercise test on a treadmill), and PA (quantity and energy expenditure [EE]), were measured and compared with aged-matched reference values.

Results. Strength of upper and lower extremity muscles, and VO_2peak were significantly lower compared to reference values. Mean Z-scores ranged from ?1.2 to ?2.9 for muscle strength, and from ?1.7 to ?4.1 for VO2peak. EE ranged from 73 – 84% of predicted EE. 6MWD was significantly associated with muscle strength of hip abductors and foot dorsal flexors. VO_2peak was significantly associated with strength of hip flexors, hip abductors, knee extensors, foot dorsal flexors, and calf muscles.

Conclusions. These children have significantly reduced muscle strength, 6MWD, VO_2peak and lower levels of PA, compared to reference values. VO_2peak and 6MWD were significantly associated with muscle strength, especially with hip abductor and ankle muscles. Therefore, even in independent ambulating children training on endurance and muscle strength seems indicated.     

Chronotropic incompetence response to exercise in congestive heart failure,relationship with the cardiac autonomic status

In chronic congestive heart failure (CHF), attenuated heart rate response to exercise, a manifestation of chronotropic incompetence (CI), contributes to limiting exercise capacity. The present study was thus conducted to evaluate the respective role of chronic attenuation of cardiac vagal tone associated with depressed baroreflex sensitivity or affected cardiac sympathetic responsiveness in CHF patients with CI. Spontaneous cardiac baroreflex sensitivity (BRS) assessed by sequence method and spectral‐ and time‐domain analysis of heart rate variability (HRV) were analysed in 21 chronic CHF patients. All patients performed a symptom‐limited exercise test with measurement of gas exchange. Chronic incompetence which was defined as failure to achieve ≥80% of the heart rate reserve (%HRR) given by (HR_peak – HR_rest)/(predictive maximal heart rate – HR_rest) was observed in 14 (66%) patients. There was no significant difference in age, heart rate, peak oxygen uptake or left ventricular ejection fraction between the patients with and without CI. Although there was no significant difference in BRS, low frequency power of HRV in normalized units (LFnu) and SDNN were significantly lower in CI patients. Percentage of HRR correlated significantly with LFnu on 15 min (r=0·64, P<0·005) and, with LFnu on 24 h (r=0·52, P<0·01), SDNN (r=0·48, P=0·03) and SDANN (r=0·48, P=0·03), but not BRS (r=0·04, P=NS). Autonomic nervous system derangement is a complex process in CHF. The role of basal depressed cardiac sympathetic tone seems to contribute more closely than depressed baroreflex sensitivity to the impaired heart rate response to exercise frequently observed in CHF patients.     

The validity and reliability of the Incremental Shuttle Walk Test and Six-minute Walk Test compared to an Incremental Cycle Test for people who have had a mild-to-moderate stroke

ObjectiveTo determine the construct validity and test re-test reliability of the Six-minute Walk Test (6MWT) and Incremental Shuttle Walk Test (ISWT) in the sub-acute recovery phase following mild-to-moderate severity stroke.Participants40 stroke patients (mean age: 68.27 years, SD: 13.48) of median National Institutes of Health Stroke Scale (NIHSS) score 1.2 (range: 0 to 8) within six months of stroke.MethodEach participant completed one Incremental Cycle Test (ICT) followed by two ISWT and two 6MWT in a randomised order. Pearson’s Correlation Coefficients were used to determine the validity and Bland Altman plots were used to determine the test re-test reliability.ResultsThe Incremental Cycle Test (ICT) was positively correlated with the ISWT (r = 0.59, 95% confidence intervals 0.35 to 0.76, P = 0.001) and the 6MWT (0.55, 0.35 to 0.71, P < 0.001). The correlation of the ICT with the ISWT and 6MWT was higher for the 17 patients with no residual (ISWT: r = 0.79, P < 0.001; 6MWT: 0.826, P < 0.001) compared to mild-to-moderate neurological impairment (ISWT: r = 0.45, P = 0.03; 6MWT: r = 0.38, P = 0.08). Test–retest reliability for both the ISWT and the 6MWT showed that there was some variability between the first and second tests with a better performance on the second test.ConclusionThe ISWT and 6MWT have a significant, modest correlation with the ICT for stroke patients in the sub-acute recovery phase. The ISWT and 6MWT are not strongly correlated with ICT (VO₂ peak) in a stroke population that is disabled. The test–retest reliability of the ISWT and 6MWT indicated that two tests may be needed to accurately assess an individual’s capabilities.     

The Influence of Change in Cardiorespiratory Fitness With Short-Term Exercise Training on Mortality Risk From The Ball State Adult Fitness Longitudinal Lifestyle Study

ObjectiveTo assess the influence of changes in cardiorespiratory fitness (CRF) after exercise training on mortality risk in a cohort of self-referred, apparently healthy adults.Patients and MethodsA total of 683 participants (404 men, 279 women; mean age: 42.7±11.0 y) underwent two maximal cardiopulmonary exercise tests (CPX) between March 20, 1970, and December 11, 2012, to assess CRF at baseline (CPX1) and post-exercise training (CPX2). Participants were followed for an average of 29.8±10.7 years after their CPX2. Cox proportional hazards models were performed to determine the relationship of CRF change with mortality, with change in CRF as a continuous variable, as well as a categorical variable. A Wald chi-square test was used to compare the coefficients estimating the relationship of peak oxygen consumption (VO_2peak) at CPX1 with VO_2peak measured at CPX2 with time until death for all-cause mortality.ResultsDuring the follow-up period there were 180 deaths. When assessed independently, there were 20% (95% CI, 10–49%) and 38% (95% CI, 7–66%) lower mortality risks per 1 metabolic equivalent improvement in CRF (P<.01) in men and women, respectively, after multivariable adjustment. Those that remained unfit had ～2-fold higher risk for all-cause mortality compared with those that remained fit and CRF at CPX2 was a stronger predictor of all-cause mortality than at CPX1 (P=.02).ConclusionImproving CRF through exercise training lowers mortality risk. Clinicians should encourage individuals to participate in exercise training to improve CRF to lower risk of mortality.     

The validity and reliability of the ADL-Glittre test for children

Objective: The ADL-Glittre was created to assess more comprehensively the essential activities of daily living in adults with chronic obstructive pulmonary disease. The aim of this study was to validate the ADL-Glittre test adapted for children (TGlittre-P) and verify its reliability. Methods: This is a cross-sectional study with 87 healthy children aged 6 to 14 years (mean 10.36 ± 2.32 years). Biometric and spirometry data were collected from all participants. On the same day, part of the sample (36 children included in the validation process) performed two 6MWT and two TGlittre-P (30-minute interval between them). The other part of the sample just performed two TGlittre-P for the reliability process. Pearson and Spearman correlation tests were used to verify the correlation between the time spent on the TGlittre-P and the distance walked in the 6MWT. The intraclass correlation coefficient (ICC) was also used to assess the reproducibility of the TGlittre-P. Results: The TGlittre-P showed a moderate negative correlation with the 6MWT (r = ?0.490; p = 0.002; 95%CI ?0.712 to ?0.233). However, the behavior of the physiological variables that were monitored during the tests was similar and showed to be reproducible (ICC = 0.843; p = 0.000; 95%CI 0.695 to 0.911). Conclusion: The TGlittre-P proved to be a valid and reliable assessment of the functional capacity of healthy children aged 6 to 14 years.     

Are cardiovascular and metabolic responses to field walking tests interchangeable and obesity-dependent?

Purpose: To investigate if cardiovascular and metabolic responses to the six-minute walk test (6MWT) and incremental shuttle walking test (ISWT) are in agreement with cardiopulmonary exercise testing (CPX) and determine if both submaximal tests are interchangeable in obese and eutrophic individuals.

Method: Observational and cross-sectional study included 51 obese women (ObG) and 21 controls (CG) (20–45 years old). Subjects underwent clinical evaluation, CPX, the 6MWT and ISWT. We applied Bland–Altman plots to assess agreement between walking tests and CPX. Correlation analysis assessed relationships between key variables.

Results: There was an agreement between CPX and both the 6MWT [oxygen uptake (VO₂ mL?kg^?1?min^?1)?=?6.9 (CI: 5.7–8.1), and heart rate (bpm)?=?37.0 (CI: 33.3–40.7)] and ISWT [VO₂ (mL?kg^?1?min^?1)?=?6.1 (CI: 4.9–7.3), and heart rate (bpm)?=?36.2 (CI: 32.1–40.3)]. We found similar cardiovascular and metabolic responses to both tests in the ObG but not in the CG. Strong correlations were demonstrated between 6MWT and ISWT variables: VO₂ ( r?=?0.70); dyspnoea (r?=?0.80); and leg fatigue (r?=?0.70).

Conclusions: 6MWT and ISWT may both hold interchangeable clinical value when contrasted with CPX in obese women and may be a viable alternative in the clinical setting when resources and staffing are limited.

• Implications for Rehabilitation

• Obesity is a worldwide epidemic, with high prevalence in women, and it is associated to impaired cardiorespiratory fitness and functional capacity as well as high mortality risk.

• Assessing oxygen uptake by means of cardiopulmonary exercise testing is the gold standard method for evaluating and stratifying cardiorespiratory fitness, however it is not ever applied due to costs and staffing.

• Walking field tests may be a cost-effective approach that provides valuable information regarding the functional capacity in agreement to metabolic and cardiovascular responses of cardiopulmonary exercise testing.

     

Normalized muscle strength, aerobic capacity, and walking performance in chronic stroke: a population-based study on the potential for endurance and resistance training

Severinsen K, Jakobsen JK, Overgaard K, Andersen H. Normalized muscle strength, aerobic capacity, and walking performance in chronic stroke: a population-based study on the potential for endurance and resistance training.

Objectives

To assess muscle strength, aerobic capacity, and walking performance compared with normative values in chronic hemiparetic stroke patients and, thereby, to investigate the potential for endurance and resistance training. Second, to study the relations between muscle strength, aerobic capacity, and walking performance using normalized test values.

Design

Population-based, cross-sectional study.

Setting

University hospital, outpatient clinic.

Participants

Patients (N=48) aged 50 to 80 years with reduced muscle strength and walking capacity due to an ischemic stroke 6 to 36 months prior to recruitment.

Interventions

None.

Main Outcome Measures

Peak oxygen consumption (Vo₂peak) and isometric knee extensor muscle strength at the paretic knee were expressed as absolute and normalized values using normative data. The six-minute walk test (6MWT) and the habitual ten-meter walk test (10MWT) were secondary parameters.

Results

Peak Vo₂ was 77% (95% confidence interval [CI], 71–84) of the expected value, and the strength of the paretic knee was 71% (95% CI, 64–78), whereas walking speed (10MWT) was 59% (95% CI, 52–66) and walking distance (6MWT) was 59% (95% CI, 52–67). The normalized Vo₂peak correlated to the normalized 6MWT (r=.58; P<.001) and normalized 10MWT (r=.53; P<.001). Normalized strength of the paretic knee correlated to normalized 6MWT (r=.40; P<.01) and normalized 10MWT (r=.31; P<.05).

Conclusions

Lower extremity muscle strength and aerobic capacity are related to walking performance, which suggests a potential for endurance and resistance training in rehabilitation of walking performance in chronic hemiparesis after stroke. Correction for the influence of age, weight, and height providing normalized values improves the interpretation of severity of impairments and enables comparisons between patients.     

Estimation de la consommation pic d��oxyg��ne par la perception de l��effort chez des patients ob��ses et diab��tiques de type 2

Objectives

The main objectives of this study were: 1) to assess the validity of predicting peak oxygen uptake (.VO₂peak) from ratings of perceived exertion (RPE) during a sub-maximal graded exercise test (GXT), in obese patients with diabetes, and 2) to compare the accuracy of predictions obtained from RPE ?? 15 and RPE ?? 17. Materials and methods: Seventeen obese women with type 2 diabetes performed GXT to volitional exhaustion, in which oxygen uptake (.VO₂) and RPE were measured. Individual linear regressions between.VO₂ and RPE, that were collected during the first stages of GXT (RPE ?? 15 and RPE ?? 17), were extrapolated to RPE = 20 in order to predict.VO₂peak. Results: Actual (12.7 ± 3.6 ml.min^?1.kg^?1) and predicted.VO₂peak from RPE ?? 15 and RPE ?? 17 (13.1 ± 3.7 and 13.3 ± 3.8 ml.min^?1.kg^?1, respectively) were not significantly different. The actual.V O₂peak were significantly correlated to the predicted.VO₂peak from RPE ?? 15 and RPE ?? 17 (R = 0.89 and R = 0.92, respectively). The 95% limits of agreement analysis were ?0.4 ± 3.4 and ?0.6 ± 3.0 ml.min^?1.kg^?1 for the predictions from RPE ?? 15 and RPE ?? 17, respectively.

Conclusion

Results suggested that the RPE ?? 15 provide accurate.V O₂peak prediction in obese women with type 2 diabetes. However, the accurate of predictions was improved when the.VO₂peak was predicted from RPE ?? 17. Consequently, RPE may be used to predict.VO₂peak and to decrease the risk of cardio-vascular complications during GXT.     

Do functional walk tests reflect cardiorespiratory fitness in sub-acute stroke?

Background and purpose  

The Six-Minute Walk Test (6MWT) has been employed as a measure of functional capacity, but its relationship to cardiorespiratory fitness in stroke is not well established. Gait speed measured over short distances is commonly used as an index of walking competency following stroke. We evaluated the relationship between the 6MWT, aerobic fitness (VO₂peak) and walking competency in sub-acute stroke.     

Body composition,maximal aerobic performance and inflammatory biomarkers in endurance-trained athletes

This study was designed to examine the relationships between body composition, cardiorespiratory fitness and simultaneously measured inflammatory parameters in endurance-trained athletes. In 20 well-trained rowers (19·0 ± 2·9 years; 185·6 ± 4·8 cm; 85·7 ± 10·8 kg; 17·1 ± 5·1% body fat; maximal oxygen consumption [VO₂max]: 63·9 ± 8·5 ml min⁻¹ kg⁻¹), body composition was measured by dual-energy X-ray absorptiometry and cardiorespiratory fitness by direct VO₂max test. Twelve inflammatory factors [interleukin (IL)-2, IL-4, IL-6, IL-8, IL-10, vascular endothelial growth factor, interferon-gamma (IFN-γ), tumour necrosis factor-alpha, IL-1α, IL-1β, monocyte chemoattractant protein-1 (MCP-1), epidermal growth factor (EGF)] were analysed from serum samples. Serum IFN-γ was related (P<0·05) to fat-free mass (FFM) (r = −0·56) and muscle mass (r = −0·50). The stepwise regression analysis showed that IFN-γ explained 27·5%, and IFN-γ and IL-6 together explained 39·8% of the variability of FFM, while IFN-γ explained 21·1%, and IFN-γ together with EGF explained 36·6% of the variability of muscle mass in male rowers. Serum IL-8 (r = −0·65) and VEGF (r = −0·48) correlated (P<0·05) with VO₂max kg⁻¹. Serum IL-8 explained 38·5% of the variability of VO₂max kg⁻¹. Significant correlations were also found among several inflammatory parameters, indicating that various inflammatory cytokines act on the body as an ensemble. In conclusion, this cross-sectional study in endurance-trained male rowers showed that FFM and muscle mass were negatively correlated with serum IFN-γ level, whereas cardiorespiratory fitness was negatively related to serum IL-8 level.     

The associations between peak O2 consumption and leptin in 10‐ to 12‐year‐old boys

The aim of this study was to assess the associations of circulating levels of leptin with the peak O₂ consumption (VO_2peak) in 10 ‐ to 12‐year‐old boys of different BMI selected by Cole et al. (BMJ, 320,2000,1–6): total group (n = 248), normal (n = 190), overweight (n = 34) and obese (n = 24). We hypothesized that there is a close relationship in overweight and obese subgroups of boys with relative VO_{2peak kg}^?1(ml min^?1 kg^?1) and leptin. Most of the subjects were Tanner stage 2. Peak O₂ consumption was measured directly using an increasing incremental protocol until volitional exhaustion on an electronically braked cycle ergometer. The expired gas was sampled continuously breadth‐by‐breadth mode for the measurement of oxygen consumption (MetaMax, Germany). Blood samples were obtained after an overnight fast from an antecubital vein for leptin measurements. Peak O₂ consumption (l min^?1) was higher or lower (ml min^?1 kg^?1) in overweight and obese groups, compared with normal BMI group. Leptin was higher in overweight and obese groups, compared with normal BMI group. Peak O₂ consumption (l min^?1) correlated significantly with leptin only in total group (n = 248, r   =   0·196). Contrary, relative VO_2peak kg^?1 correlated significantly and negatively with leptin. The relationship was highest on the total group (r   =  ?0·674). We can conclude that leptin first of all correlated negatively with relative peak O₂ consumption. Absolute VO_2peak correlated with leptin only in total group.     

Determinants of shuttle run performance in the prediction of peak VO2 in wheelchair users

Purpose. The purpose of this study was to determine the impact of ergonomic and environmental variations on indoor shuttle run (SR) performance in wheelchair sportsmen.

Methods. Eleven experienced male wheelchair sportsmen performed three 25-m SRs in random order with varying turning capacity (TC) and mechanical resistance (MR): condition NN where participants used their sports wheelchair on a tartan surface, condition RN with increased MR, and condition RD with limited TC. Metabolic data were continuously recorded using a portable K4b² system.

Results. Friedman ANOVA with Wilcoxon a posteriori testing indicated similar VO_2peak values in all three tests. SR performance, however, was significantly different across the three test conditions (NN: 536.18 ± 119.09 s; RN: 488.82 ± 119.84 s; RD: 404.91 ± 88.41 s). SR performance contributed for 28% of the explained variance of the measured VO_2peak. The addition of TC or MR or both increased the explained variance to 32, 38 and 41%, respectively.

Conclusions. These findings demonstrate a significant impact of variations in floor surface and wheelchair-user interface on SR performance. The findings also suggest that strong reservations have to be made regarding the validity of a SR test, as predictor of VO_2peak in a wheelchair user population.     

Function of remote non-infarcted myocardium after STEMI: analysis with cardiovascular magnetic resonance

To evaluate remote myocardial function after ST-elevation myocardial infarction (STEMI) and the impact of infarct size (IS) using cardiovascular magnetic resonance (CMR). 161 patients and 15 controls underwent CMR at 1st week and 6th month after STEMI. Using the 17-segments model, segments were categorized into infarcted, adjacent and remote myocardium. Relative systolic wall thickening (SWT, %) was assessed using the centerline method. IS (% of left ventricular mass) was determined in late enhancement imaging. Overall, in remote myocardium, SWT was comparable (83 ± 32) to controls (77 ± 25, P = .5) and did not increase significantly (P = .2) at the 6th month (88 ± 35, P = .3 vs. control). When IS was categorized into tertiles (<13.6%, (n = 49), 13.7–28.2%, (n = 60), >28.2%, (n = 52)), SWT in the remote area at the 1st week was not different from controls, regardless of infarct size (p between .2 and .8 for all tertiles). At 6 months, SWT was larger compared to controls only in small infarctions (98 ± 34 vs. 77 ± 25, P = .03). In medium and large infarctions there was no difference in SWT of the remote area compared to controls (87 ± 33 and 79 ± 34, P = .3 and P = .09) and there was no significant increase at 6 months (P between .2 and .9). In remote myocardium there was no difference in contractility compared to controls after STEMI. After 6 month a slight hypercontractility can only be observed in small infarctions. In medium and large infarctions no difference of SWT in remote myocardium compared to controls can be observed.