Navegando por Palavras-chave "limits of agreement"

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    Peak VO2 correction for fat-free mass estimated by anthropometry and DEXA
    (Lippincott Williams & Wilkins, 2001-11-01) Neder, José Alberto [UNIFESP]; Lerario, Maria Cristina [UNIFESP]; Lazaretti-Castro, Marise [UNIFESP]; Sachs, Anita [UNIFESP]; Nery, Luiz Eduardo [UNIFESP]; Univ Glasgow; Universidade Federal de São Paulo (UNIFESP)
    Purpose: Anthopometric (ANTHRO) and dual-energy x-ray absorptiometric (DEXA) estimates of total body and leg fat-free masses (FFM) were obtained in 77 randomly selected sedentary men and women, aged 20-80: intermethod limits of agreement and their clinical significance, as inferred from the differences on peak (V)over dotO(2) corrected for FFMANTHRO and FFMDEXA, were determined. Methods: Limits of agreement were calculated as mean bias +/- 95% confidence intervals: peak (V)over dotO(2) at maximum cycle ergometry was related to FFM(ANTHRO)and FFMDEXA by using both standard (y.x(-1)) and power function ratios (allometry). Results: Data distribution of the ANTHRO-DEXA differences presented significant heteroscedasticity in both sexes, i.e., differences were proportional to the mean (P<0.05). After logarithmic transformation, the mean bias 95% limits of agreement were expressed as ratios (ANTHRO-DEXA(-1) x/ error ratio): these corresponded to 0.95 x/divided by 1.11 or 0.99 x/divided by 1.15 for total body FFM and 0.90 x/divided by 1.10 or 1.02 x/divided by 1.07 for leg FFM in men and women, respectively. in addition, we found different allometric exponents for FFMANTHRO and FFMDEXA: the intermethod differences, therefore, increased after power function expression (P<0.05). Conclusion: Discrepancies between ANTHRO and DEXA measurements of FFM depend on the magnitude of the estimate: differences are typically within 10 to 15%. Importantly, FFM-corrected peak (V)over dotO(2) values can vary according to the method chosen for body composition assessment, especially when allometry is used for peak (V)over dotO(2) correction. These results demonstrate that ANTHRO-DEXA differences in FFM estimation do have relevant practical consequences for the analysis of maximum aerobic capacity in nontrained humans.
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    A simplified strategy for the estimation of the exercise ventilatory thresholds
    (Lippincott Williams & Wilkins, 2006-05-01) Neder, Jose Alberto [UNIFESP]; Stein, R.; Universidade Federal de São Paulo (UNIFESP); Univ Fed Rio Grande Sul
    Purpose: To analyze the limits of agreement between exercise ventilatory threshold values (VT1 and VT2) estimated from a combination of pulmonary gas exchange and ventilatory variables (cardiopulmonary exercise testing) and those derived from an alternative approach based oil the ventilatory response only (VE. ventilometry). Methods: Forty-two nontrained subjects (24 males, aged 18-48, peak VO2 = 33.1 +/- 8.6 mL(.)min(-1.)kg(-1)) performed a maximum incremental cardiopulmonary exercise testing on all electromagnetically braked cycle ergometer. the participants breathed through a Pilot tube (Cardio(2) System (TM), MGC) and a fixed-resistance ventilometer (Micromed, Brazil), which were connected in series. HR values at the estimated VT (VTHR1 and VTHR2) were obtained by the conventional method (ventilatory equivalents. end-expiratory pressures for O-2 and CO2 and the V-slope procedure) and an experimental approach (VE vs time, VE/time vs time. and breathing frequency vs time). Results: There were no significant between-method differences on VTHR1, VTHR2, VTVE1, VTVE2, and peak VE (P > 0.05). After certification of data normality, a Bland-Altman analysis revealed that the mean bias 95% confidence interval of the between-method differences were lower for VTHR2 than VTHR1 (2 +/- 9 and 0 +/- 17 bpm, respectively). VTHR2 according to ventilometry differed more than 10 bpm from the standard procedure in 3 out of 42 subjects (9%). Between-method differences were independent of the level of fitness, as estimated from peak VO2 (P > 0.05). Conclusions: A simplified approach, based oil the ventilatory response as a function of time, call provide acceptable estimates of the exercise ventilatory thresholds-especially VT2-during ramp-incremental cycle ergometry. This new strategy might prove to be useful for exercise training prescription in nontrained adults.