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Lower body positive pressure (LBPP), or 'anti-gravity' treadmills ® have become increasingly popular among elite distance runners. However, to date, few studies have assessed the effect of body weight support (BWS) on the metabolic cost of running among elite runners. This study evaluated how BWS influenced the relationship between velocity and metabolic cost among 6 elite male distance runners. Participants ran three- 16 minute tests consisting of 4 stages of 4 minutes at 8, 7, 6 and 5 min⋅mile-1 pace (3.35, 3.84, 4.47 and 5.36 m⋅s-1), while maintaining an aerobic effort (Respiratory Exchange Ratio ≤1.00). One test was run on a regular treadmill, one on an anti-gravity treadmill with 40% BWS and one with 20% BWS being provided. Expired gas data were collected and regression equations used to determine and compare slopes. Significant decreases in oxygen uptake (...O2) were found with each increase in BWS (p < 0.001). At 20% BWS, the average decrease in net VO2 was greater than proportional (34%), while at 40% BWS, the average net reduction in VO2 was close to proportional (38%). Across velocities, the slope of the relationship between VO2 and velocity (...O2/Δv) was steeper with less support. The slopes at both the 20% and 40% BWS conditions were similar, especially when compared to the regular treadmill. Variability in VO2 between athletes was much greater on the LBPP treadmill and was greater with increased levels of BWS. In this study we evaluated the effect of body weight support on ...O2 among elite distance runners. We have shown that oxygen uptake decreased with support, but not in direct proportion to that support. Further, because of the high variability in oxygen uptake between athletes on the LBPP treadmill, prediction equations may not be reliable and other indicators (heart rate, perceived exertion or directly measured oxygen uptake) should be used to guide training intensity when training on the LBPP treadmill. [ABSTRACT FROM AUTHOR]

Background: Since anthropometric variables are critical to the creation of pulmonary nomograms for FVC, FEV1, and other volumes and capacities, it is logical that anthropometric variables also influence the values of the maximal respiratory pressures (MRPs). Since nomograms are race-specific, it is important that tribe-specific tables of normal maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) be developed. To date normal tables for MRPs do not exist for Navajo children., Objective: Therefore the purpose of this study was to derive MRP normative reference values for Navajo children in the age range of 6-14 years., Methods-Participants and Measurements: A cross-sectional study was undertaken with a representative sample of 534 healthy children, ages 6-14 years, attending Navajo Nation elementary schools in Arizona. MIP and MEP were measured., Results: Test results from 275 girls and 259 boys met American Thoracic Society quality control standards and showed that MRPs all increased with height. Mean MIP in cm H2 O was 77 for boys and 67 for girls with lower limits of 44 and 40, respectively. Mean MEP in cm H2 O was 75 for boys and 66 for girls with the lower limits of 42 and 38, respectively., Conclusion: Since the data were collected from the population of interest, the resulting MIP and MEP reference equations should be used when testing Navajo children ages 6-14 years., (Copyright © 2013 Wiley Periodicals, Inc.)

Spirometry is the most important tool in diagnosing pulmonary disease and is the most frequently performed pulmonary function test. Since respiratory disease is the single greatest cause for morbidity and mortality on the Navajo Nation, the purpose of this study was to create new age and race-specific pulmonary nomograms for Navajo children. Five hundred fifty-eight healthy children, ages 6-14 years, attending Navajo Nation elementary schools in Arizona, were asked to perform spirometry to develop population-specific and tribe-specific nomograms for forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), and FEV1 Ratio (FEV1/FVC). Spirometry tests from 284 girls and 274 boys met American Thoracic Society quality control standards. Lung function values, except for FEV1/FVC, all increased with height. The lower limit of the normal range for FEV1/FVC was 80%. The spirometry reference equations from the healthy boys and girls were developed. Height and the natural log of height were significant predictors of FEV1, FVC, and FEF(25-75%) in the gender-specific models. The resulting population-specific spirometry reference equations should be used when testing Navajo children ages 6-14 years. However, the use of the NHANES III spirometry reference equations for Caucasian children may not result in significant misclassification in clinical settings providing that a maximal effort is given by the Navajo child being tested.

Background: Although several reports have shown an adverse cardiovascular and metabolic risk profile associated with childhood obesity, few reports have examined the effects of childhood obesity on pulmonary function., Objective: The purpose of this study was to examine the influence of obesity on pulmonary function in Navajo and Hopi children., Methods: Subjects included 256 (110 males, 146 females) Hopi children 6-12 years of age and 557 (274 males, 283 females) Navajo children 6-12 years of age (N = 813). The body mass index was used to classify subjects as normal weight, overweight, or obese on the basis of international reference values. Forced vital capacity (FVC), forced expired volume in one second (FEV1), FEV1% (FEV1 to FVC ratio; FEV1/FVC), and forced expiratory flow between 25%-75% of vital capacity (FEF25-75) were determined according to the American Thoracic Society recommendations., Results: Approximately 26% of Navajo and Hopi children were defined as overweight additional 16% (14.6% of boys and 17.7% of girls) were defined as obese. In general, the patterns showed an increase in pulmonary function between normal weight and overweight children and a decrease in pulmonary function of obese children. Significant differences among groups existed for FEV1% and FEF25-75 in boys and FVC and FEV1 in girls., Conclusions: The results indicate the pulmonary consequences of obesity in children and provide further evidence of the adverse consequences of pediatric obesity among Native Americans.