Cross-validation of Peak Oxygen Consumption Prediction Models From OMNI Perceived Exertion.

This study cross-validated statistical models for prediction of peak oxygen consumption using ratings of perceived exertion from the Adult OMNI Cycle Scale of Perceived Exertion. 74 participants (men: n=36; women: n=38) completed a graded cycle exercise test. Ratings of perceived exertion for the overall body, legs, and chest/breathing were recorded each test stage and entered into previously developed 3-stage peak oxygen consumption prediction models. There were no significant differences (p>0.05) between measured and predicted peak oxygen consumption from ratings of perceived exertion for the overall body, legs, and chest/breathing within men (mean±standard deviation: 3.16±0.52 vs. 2.92±0.33 vs. 2.90±0.29 vs. 2.90±0.26 L·min(-1)) and women (2.17±0.29 vs. 2.02±0.22 vs. 2.03±0.19 vs. 2.01±0.19 L·min(-1)) participants. Previously developed statistical models for prediction of peak oxygen consumption based on subpeak OMNI ratings of perceived exertion responses were similar to measured peak oxygen consumption in a separate group of participants. These findings provide practical implications for the use of the original statistical models in standard health-fitness settings.

Validity of a wheelchair perceived exertion scale (wheel scale) for arm ergometry exercise in people with spina bifida.

This study assessed the concurrent and construct validity of the Borg 6-20 Scale and WHEEL Scale during arm ergometry exercise stress testing in (n = 24) adolescents and adults with spina bifida. Significant, moderate, positive correlations were observed between power output and relative heart rate and power output to relative VO2peak. Further, a moderate, significant correlation between physiologic criterion variables and the rating of perceived exertion derived from the Borg Scale and the WHEEL Scale was found. Concurrent validity was supported by the following findings: (1) relative heart rate was significantly correlated with the Borg (Kendall's τ = .41) and WHEEL Scales (τ = .44), and relative VO2 was significantly correlated with the Borg (τ = .46) and WHEEL Scales (τ = .47); (2) content validity was supported by the finding that the Borg and WHEEL Scales shared significant variance (τ = .70), demonstrating internal consistency. The WHEEL Scale shows strong potential for use in this cohort subsequent to further testing and validation.

CT appearances of pleural tumours.

Computed tomography (CT) is the imaging technique of choice for characterizing pleural masses with respect to their location, composition, and extent. CT also provides important information regarding invasion of the chest wall and surrounding structures. A spectrum of tumours can affect the pleura of which metastatic adenocarcinoma is the commonest cause of malignant pleural disease, while malignant mesothelioma is the most common primary pleural tumour. Certain CT features help differentiate benign from malignant processes. This pictorial review highlights the salient CT appearances of a range of tumours that may affect the pleura.

Complex hybridization dynamics between golden-winged and blue-winged warblers (Vermivora chrysoptera and Vermivora pinus) revealed by AFLP, microsatellite, intron and mtDNA markers.

Blue-winged (Vermivora pinus) and golden-winged warblers (Vermivora chrysoptera) have an extensive mosaic hybrid zone in eastern North America. Over the past century, the general trajectory has been a rapid replacement of chrysoptera by pinus in a broad, northwardly moving area of contact. Previous mtDNA-based studies on these species' hybridization dynamics have yielded variable results: asymmetric and rapid introgression from pinus into chrysoptera in some areas and bidirectional maternal gene flow in others. To further explore the hybridization genetics of this otherwise well-studied complex, we surveyed variation in three nuclear DNA marker types--microsatellites, introns, and a panel of amplified fragment length polymorphisms (AFLPs)--with the goal of generating a multilocus assay of hybrid introgression. All markers were first tested on birds from phenotypically and mitochondrially pure parental-type populations from outside the hybrid zone. Searches for private alleles and assignment test approaches found no combination of microsatellite or intron markers that could separate the parental populations, but seven AFLP characters exhibited significant frequency differences among them. We then used the AFLP markers to examine the extent and pattern of introgression in a population where pinus-phenotype individuals have recently invaded a region that previously supported only a chrysoptera-phenotype population. Despite the low frequency of phenotypic hybrids at this location, the AFLP data suggest that almost a third of the phenotypically pure chrysoptera have introgressed genotypes, indicating the presence of substantial cryptic hybridization in the history of this species. The evidence for extensive cryptic introgression, combined with the lack of differentiation at other nuclear loci, cautions against hybrid assessments based on single markers or on phenotypic traits that are likely to be determined by a small number of loci. Considered in concert, these results from four classes of molecular markers indicate that pinus and chrysoptera are surprisingly weakly differentiated and that far fewer genetically 'pure' populations of chrysoptera may exist than previously assumed, two findings with broad implications for the conservation of this rapidly declining taxon.

Effect of a maximal treadmill test on percent body fat using leg-to-leg bioelectrical impedance analysis in children.

AIM: The purpose of this investigation was to determine the effect of a maximal treadmill exercise test on percent body fat (%BF) in children using leg-to-leg bioelectrical impedance analysis (LBIA) (Tanita Model #TBF-300A). METHODS: Fifty-four children (24 females; 30 males) between 7-10 years of age participated in this study. LBIA measures of %BF were obtained immediately before and within 5 min after completing a maximal oxygen consumption test on a motorized treadmill. RESULTS: No pre- to post-test differences in %BF were observed in either group (mean difference: females 1.6%, males 1.5%). Impedance values significantly decreased postexercise (P < 0.05) in the female subjects. No significant differences were observed for fat mass, fat free mass, total body water or body weight postexercise when compared to pre-exercise values in either group. Correlations (P = 0.0001) of 0.997 were observed between pre- and postexercise measures of %BF. CONCLUSIONS: A maximal treadmill exercise test conducted prior to LBIA has no impact on %BF in children. Therefore, normal daily activities performed prior to LBIA assessment may have a limited impact on LBIA body composition measurement in children. As such, compliance with stringent pretesting exercise guidelines may not be essential when using LBIA to assess %BF in children.

HRCT diagnosis of diffuse parenchymal lung disease: inter-observer variation.

BACKGROUND: This study was designed to measure inter-observer variation between thoracic radiologists in the diagnosis of diffuse parenchymal lung disease (DPLD) using high resolution computed tomography (HRCT) and to identify areas of difficulty where expertise, in the form of national panels, would be of particular value. METHODS: HRCT images of 131 patients with DPLD (from a tertiary referral hospital (n = 66) and regional teaching centres (n = 65)) were reviewed by 11 thoracic radiologists. Inter-observer variation for the first choice diagnosis was quantified using the unadjusted kappa coefficient of agreement. Observers stated differential diagnoses and assigned a percentage likelihood to each. A weighted kappa was calculated for the likelihood of each of the six most frequently diagnosed disease entities. RESULTS: Observer agreement on the first choice diagnosis was moderate for the entire cohort (kappa = 0.48) and was higher for cases from regional centres (kappa = 0.60) than for cases from the tertiary referral centre (kappa = 0.34). 62% of cases from regional teaching centres were diagnosed with high confidence and good observer agreement (kappa = 0.77). Non-specific interstitial pneumonia (NSIP) was in the differential diagnosis in most disagreements (55%). Weighted kappa values quantifying the likelihood of specific diseases were moderate to good (mean 0.57, range 0.49-0.70). CONCLUSION: There is good agreement between thoracic radiologists for the HRCT diagnosis of DPLD encountered in regional teaching centres. However, cases diagnosed with low confidence, particularly where NSIP is considered as a differential diagnosis, may benefit from the expertise of a reference panel.

Pulmonary complications following bone marrow transplantation.

Pulmonary complications account for significant morbidity and mortality in patients following bone marrow transplants (BMT). They are distinct from other immunosuppressed patients in that there is a predictable course of immunosuppresion and therefore of likely pulmonary complications. This is important when interpreting abnormal radiology as the predictable time course will enable narrowing the differential diagnoses to certain pulmonary complications that characteristically occur at a particular time following BMT. Early recognition and correct treatment of the pulmonary complications should minimize the significant mortality and morbidity. This review aims to discuss the role of radiology in the diagnosis and management of pulmonary complications following BMT.

The solitary pulmonary nodule.

The solitary pulmonary nodule will be found increasingly by the use of newer imaging techniques, including computed tomography (CT) screening. The aim must be to have an approach that avoids unnecessary surgery or biopsy with their attendant risks. Plain films characterisation, CT assessment, including densitometry and enhancement, and growth patterns are discussed and evaluated. The use of Bayes theorem to guide these assessment strategies is also described.

OMNI scale perceived exertion at ventilatory breakpoint in children: response normalized.

PURPOSE: The Children's OMNI Scale of Perceived Exertion was used to identify a response normalized rating of perceived exertion (RPE)-Overall, RPE-Legs, and RPE-Chest that corresponds to the ventilatory breakpoint (Vpt) in 8- to 12-yr-old female and male children. METHODS: Subjects were a priori stratified into two fitness groups on the basis of peak oxygen uptake (VO2 peak): average (A) (41.0-49.0 mL x kg(-1) x min(-1); N = 24) and above average (AA) (50.0-58.0 mL x kg(-1) x min(-1); N = 24). Vpt was determined by a progressive cycle ergometer protocol to VO2 peak. RESULTS: A gender effect was not observed for any descriptive or dependent variable. Mean VO2peak for the A group was 1.72 L x min(-1) and for the AA group 2.04 L x min(-1). Vpt corresponded to 64.0% VO2 peak for A and 74.0% VO2peak for AA. RPE-Overall (mean A and AA, 6.1), RPE-Legs (mean A and AA, 7.2), and RPE-Chest (mean A and AA, 4.5) did not differ between the fitness groups. CONCLUSION: Findings indicated that undifferentiated and differentiated RPE-Vpt were similar between female and male children who varied in VO2peak and Vpt. A comparatively stable RPE-Vpt for 8- to 12-yr-old children that vary in VO2peak and Vpt indicates a group normalized perceptual response.

Standardized scaling procedures for rating perceived exertion during resistance exercise.

The purpose of this project was to determine the validity of standardized Borg scale instructions and scale anchoring procedures to measure active muscle rating of perceived exertion and overall rating of perceived exertion during resistance exercise. Anchoring procedures were determined for each of 7 exercises before the completion of 2 counterbalanced experimental trials. In one trial, subjects lifted 90% of 1 repetition maximum (1RM) 5 times. In the other, subjects lifted 30% of 1RM 15 times. Adjusted R2 and SEMs were used to determine linearity of Borg 15-category scale responses with respect to repetitions at equal work increments for both the group and the sum of the individuals. Both group and individual responses had high adjusted R2 and low SEM values. These results suggest that the current scaling instructions used with the Borg 15-category scale are valid for use during resistance exercise.

Intermodal comparison of energy expenditure at exercise intensities corresponding to the perceptual preference range.

PURPOSE: This study compared the rate of energy expenditure among six popular exercise machines at intensities corresponding to ratings of perceived exertion (RPE) for fairly light (RPE-11), somewhat hard (RPE-13), and hard (RPE-15) in 9 healthy men and 10 healthy women. METHODS: A maximal exercise test on each exercise machine was used to anchor the Borg 15-point category scale. Subjects performed three submaximal exercise tests at selected RPEs on a treadmill, stair-stepper, cycle ergometer, rowing ergometer, cross-country ski simulator, and rider. The submaximal tests on each exercise device were performed in random order and were 6 min in duration with 15-min rest between trials. Oxygen uptake, heart rate, and blood lactate concentration were measured during the final 2 min of each exercise intensity. RESULTS: Energy expenditure at each RPE was highest on the treadmill and ski simulator in men, and on the treadmill, ski simulator, and rowing ergometer in women. Energy expenditure in men and women at all RPEs was lowest on the rider and cycle ergometer. Energy expenditure at a given RPE was greater in men than women on all exercise machines, but men and women used a similar percentage of their machine specific peak oxygen uptake at each RPE on all machines. Heart rate was generally similar among the machines and between both men and women at each RPE. CONCLUSIONS: Our results indicated that there are large differences in energy expenditure between exercise machines and between men and women at intensities perceived to be fairly light, somewhat hard, and hard. Consequently, subjects can expend more calories at the same RPE during treadmill and ski simulator exercise, for example, than during exercise with other devices. This may have important implications for the health benefits of different exercises and in promoting long term exercise adherence.

High levels of extra-pair paternity in an isolated, low-density, island population of tree swallows (Tachycineta bicolor).

Molecular genetic studies have suggested that apparently nonbreeding males ('floaters') may account for a significant proportion of extra-pair paternity (EPP) in avian populations. Attempts to determine the influence of breeding density on EPP are therefore confounded by the presence of a subpopulation of floaters whose numbers are difficult to estimate. To study EPP in a tree swallow (Tachycineta bicolor) population with few floaters, we chose a nestbox grid on an island with an excess of available breeding sites and very few floaters. We obtained DNA samples from 13 complete families and performed DNA profiling on them using four microsatellite loci. For comparison, we also obtained a sample of 58 extra-pair young (EPY) from a mainland population typed at five microsatellite loci. Paternity assignments among resident males in both populations were made using the microsatellite profiles and a likelihood-based statistical method. Of the 67 island nestlings typed, we found 37 (55%) nestlings from 11 (85%) different nests that were EPY. The proportion of nestlings that were EPY and the proportion of broods containing EPY did not differ significantly between island and mainland populations studied previously. There was no significant difference between island and mainland populations in the proportion of extra-pair paternities assigned among neighbouring resident males. Male breeding density does not appear to affect the ability of female tree swallows to obtain extra-pair fertilizations, at least over the range of densities studied so far. The rate of EPP has remained remarkably consistent over many years, studies and populations implying an important role of active female choice in determining EPP.

Disrupting evolutionary processes: the effect of habitat fragmentation on collared lizards in the Missouri Ozarks.

Humans affect biodiversity at the genetic, species, community, and ecosystem levels. This impact on genetic diversity is critical, because genetic diversity is the raw material of evolutionary change, including adaptation and speciation. Two forces affecting genetic variation are genetic drift (which decreases genetic variation within but increases genetic differentiation among local populations) and gene flow (which increases variation within but decreases differentiation among local populations). Humans activities often augment drift and diminish gene flow for many species, which reduces genetic variation in local populations and prevents the spread of adaptive complexes outside their population of origin, thereby disrupting adaptive processes both locally and globally within a species. These impacts are illustrated with collared lizards (Crotaphytus collaris) in the Missouri Ozarks. Forest fire suppression has reduced habitat and disrupted gene flow in this lizard, thereby altering the balance toward drift and away from gene flow. This balance can be restored by managed landscape burns. Some have argued that, although human-induced fragmentation disrupts adaptation, it will also ultimately produce new species through founder effects. However, population genetic theory and experiments predict that most fragmentation events caused by human activities will facilitate not speciation, but local extinction. Founder events have played an important role in the macroevolution of certain groups, but only when ecological opportunities are expanding rather than contracting. The general impact of human activities on genetic diversity disrupts or diminishes the capacity for adaptation, speciation, and macroevolutionary change. This impact will ultimately diminish biodiversity at all levels.

Physiological comparisons among three maximal treadmill exercise protocols in trained and untrained individuals.

The present investigation was undertaken to examine whether maximal oxygen uptake (VO2max) and anaerobic threshold (AT) measured during incremental treadmill exercise would be affected by the exercise protocol in trained and untrained individuals. Fifteen untrained men, 10 untrained women, and 12 trained individuals participated in this study. The Astrand, Bruce, and Costill/Fox protocols were selected for comparison. Each subject was tested using all three protocols and the three tests were conducted in a randomized counterbalanced order. During each test, oxygen uptake was measured every 30 s and the test was terminated according to the standard criteria. The VO2max was determined by averaging the two consecutive highest measurements, whereas AT was determined using ventilatory parameters following the V-slope technique. The Astrand, Bruce, and Costill/Fox protocols produced test durations of 9.8 (SEM 0.5), 12.4 (SEM 0.4), and 4.9 (SEM 0.3) min, respectively, in the untrained men, 9.0 (SEM 0.8), 11.0 (SEM 0.6), and 5.3 (SEM 0.6) min, respectively, in the untrained women, and 14.5 (SEM 0.5), 17.0 (SEM 0.5) and 10.4 (SEM 0.4) min, respectively, in the trained men. In the untrained men and women, no differences in VO2max were observed among the three different protocols, but AT was lower when using the Bruce compared to the Astrand protocol. In the trained men, VO2max and AT were lower when using the Bruce protocol than either the Astrand or Costill/Fox protocols. In conclusion, VO2max measured during treadmill exercise is not affected by the protocol of the test and using a running protocol of short duration (i.e. about 5 min) could be a time-efficient way of assessing VO2max in healthy untrained subjects. In trained subjects, however, a protocol consisting of running with small increments in gradient is effective in eliciting a higher VO2max. The lower AT associated with the Bruce protocol seen in both untrained and trained groups suggests this aerobic parameter is protocol dependent and this protocol dependency is not affected by training status.

Immune defense and host sociality: a comparative study of swallows and martins.

Sociality is associated with increased risks of parasitism, predation, and social competition, which may interact because social stress can reduce immunity, and parasitized individuals are more likely to fall prey to a predator. A mechanism allowing evolution of sociality in spite of high costs of parasitism is increased investment in antiparasite defenses. Here we show that the impact of parasites on host reproductive success was positively associated with the degree of sociality in the bird family Hirundinidae. However, the cost of parasitism in highly colonial species was countered by high levels of T- and B-cell immune responses. Investment in immune function among colonial species was particularly strong in nestlings, and among social species, this investment was associated with a relatively prolonged period of development, thereby leading to extended exposure to parasites. Thus, highly social species such as certain species of swallows and martins may cope with strong natural selection arising from parasites by heavy investment in immune function at the cost of a long exposure to nest parasites.

Peak oxygen consumption and skeletal muscle bioenergetics in African-American and Caucasian men.

OBJECTIVE: To compare peak oxygen consumption (VO2peak) and skeletal muscle oxidative metabolism between nine African-American and nine Caucasian men. METHODS: Subjects performed arm ergometry to exhaustion. On a separate occasion 31phosphorous-nuclear magnetic resonance spectroscopy (31P-NMRS) was used to determine the concentrations of phosphorous (Pi), phosphocreatine (PCr), and the intracellular pH of the flexor carpi radialis before and during 4 min of steady-state, wrist flexion exercise performed at 28% (15 W) of each subject's peak voluntary contraction. RESULTS: The Pi/PCr ratio was used as an indirect measure of skeletal muscle oxidative metabolism. VO2peak was lower in the African-Americans compared with the Caucasians (means +/- SD, 19.4 +/- 3.4 vs 23.3 +/- 4.0 mL x kg(-1) x min(-1)) (P < 0.05). No significant between group difference was noted in the Pi/PCr ratio at rest (0.10 +/- 0.02 both groups). However, resting pH was lower in the African-Americans (6.99 +/- 0.04 vs 7.03 +/- 0.05) (P < 0.05). Exercise caused an increase in the Pi/PCr ratio in the African-Americans (1.06 +/- 0.11), which was higher than the increase observed in the Caucasians (0.50 +/- 0.14) (P < 0.05). pH levels decreased to a lower level during exercise in the African-Americans (6.89 +/- 0.04) than in the Caucasians (6.98 +/- 0.05) (P < 0.05). CONCLUSIONS: This select group of African-American men achieved a lower VO2peak than the Caucasian men. Variations in skeletal muscle oxidative metabolic components may explain this difference.

Gender comparison of RPE at absolute and relative physiological criteria.

PURPOSE: The effect of gender on ratings of perceived exertion for the overall body (RPE-O), chest (RPE-C), legs (RPE-L), and arms (RPE-A (ski)) was determined. METHODS: Comparisons were made at, a) absolute oxygen uptake (VO2, L x min(-1); mL x kg(-1) x min(-1)) and heart rate (HR, b x min(-1)) and b) relative VO2 (%VO2max/peak) and HR (% HRmax/peak) reference criteria. Nine male and 10 female subjects were compared using a perceptual estimation paradigm for treadmill (weight bearing), simulated ski (partial weight bearing), and cycle (nonweight bearing) exercise. RPE was determined by the Borg 15-category scale. RESULTS: For each exercise mode, RPE-O, RPE-L, RPE-A (ski), and RPE-C were higher (P < 0.05) in the female than male cohort when compared at submaximal absolute VO2 criteria. RPE did not differ between female and male cohorts when compared at mode specific relative VO2 criteria. Differences in RPE-O, RPE-L, RPE-A (ski), and RPE-C were not found between female and male subjects when comparisons were made at both absolute and relative HR. Responses were consistent for the three exercise modes. CONCLUSION: RPE did not differ between gender when comparisons were made at relativized VO2 and HR reference criteria at exercise intensities between 70 and 90% of mode specific maximal/peak values.

Complex social organization reflects genetic structure and relatedness in the cooperatively breeding bell miner, Manorina melanophrys.

The cooperatively breeding bell miner, Manorina melanophrys, differs from most other cooperative breeding species in the complexity of its social system, where discrete social organization occurs on at least three levels. Microsatellite markers were used to investigate the degree of genetic structure underlying the social organization of M. melanophrys by comparing colonies, coteries and nest contingents. The genetic data confirmed behavioural observations of M. melanophrys living in male kin-based groups between which females disperse short distances to breed. Estimates of FST revealed restricted gene flow between eight colonies located within 30 km that was significantly associated with geographical distance when the two most distant colonies were included. Within a high density colony significant differences were found between coteries; analysis of the degree of relatedness between coterie members showed that this is due to related individuals associating preferentially with each other. Similarly, the contingent of individuals attending a nest were generally close relatives of the young they were aiding, supporting models invoking kin selection as the selective agency mediating helping.

Children's OMNI scale of perceived exertion: mixed gender and race validation.

PURPOSE: The newly developed Children's OMNI Scale of Perceived Exertion (category range: 0 to 10) was validated using separate cohorts of female and male, African American and white subjects. Each of the four cohorts contained 20 clinically normal, nonobese children, 8-12 yr of age. METHODS: A cross-sectional, perceptual estimation paradigm using a single multi-stage cycle ergometer test protocol was used. Oxygen uptake (VO2; mL x min(-1)), heart rate (HR; beats x min(-1)) and ratings of perceived exertion for the overall body (RPE-Overall), legs (RPE-Legs), and chest (RPE-Chest) were determined at the end of each continuously administered 3-min power output (PO) (i.e., 25, 50, 75, and 100 W) test stage. RESULTS: The range of responses over the four POs for all cohorts was VO2: 290.8 to 1204.0 mL x min(-1); HR: 89.2 to 164.4 beats x min(-1); and RPE-Overall, RPE-Legs, and RPE-Chest: 0.85 to 9.1. First-order correlation and linear regression analyses were performed for each cohort separately and the total sample using a repeated measures paradigm over the four POs. For all correlation/regression paradigms RPE-Overall, RPE-Legs, and RPE-Chest distributed as a positive linear function of both VO2 and HR; r = 0.85 to 0.94; P < 0.01. Differences between RPE-Overall, RPE-Legs, and RPE-Chest were examined with ANOVA for the repeated measures paradigm. RPE-Legs was higher (P < 0.01) than RPE-Chest and RPE-Overall at 25, 50, 75, and 100 W. RPE-Chest did not differ from RPE-Overall at 25 and 50 W but was lower (P < 0.01) than RPE-Overall at 75 and 100 W. CONCLUSION: The psycho-physiological responses provide validity evidence for use of the Children's OMNI Scale over a wide range of dynamic exercise intensities.