Physical and Fitness Characteristics of Elite Professional Rugby Union Players

This study explored the physical and fitness characteristics of elite professional rugby union players and examined the relationships between these characteristics within forwards and backs. Thirty-nine elite professional rugby union players from the New Zealand Super Rugby Championship participated in this study. Body composition was measured using dual-energy X-ray absorptiometry alongside anthropometrics. Fitness characteristics included various strength, power, speed, and aerobic fitness measures. Forwards were significantly (p ≤ 0.01) taller and heavier than backs, and possessed greater lean mass, fat mass, fat percentage, bone mass, and skinfolds. Forwards demonstrated greater strength and absolute power measures than backs (p = 0.02), but were slower and possessed less aerobic fitness (p ≤ 0.01). Skinfolds demonstrated very large correlations with relative power (r = −0.84) and speed (r = 0.75) measures within forwards, while backs demonstrated large correlations between skinfolds and aerobic fitness (r = −0.54). Fat mass and fat percentage demonstrated very large correlations with speed (r = 0.71) and aerobic fitness (r = −0.70) measures within forwards. Skinfolds, fat mass, and fat percentage relate strongly to key fitness characteristics required for elite professional rugby union performance. Individual and positional monitoring is important due to the clear differences between positions.

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Dual-Energy X-Ray Absorptiometry Measurements of Body Composition: Effects of Depth and Tissue Thickness, Including Comparisons with Direct Analysis

Clinical Science ◽

10.1042/cs0880319 ◽

1995 ◽

Vol 88 (3) ◽

pp. 319-324 ◽

Cited By ~ 51

Author(s):

Susan A. Jebb ◽

Gail R. Goldberg ◽

Graham Jennings ◽

Marinos Elia

Keyword(s):

Body Composition ◽

Fat Mass ◽

Research Work ◽

Experimental System ◽

Direct Analysis ◽

Dual Energy ◽

Tissue Thickness ◽

X Ray ◽

Few Data

1. There are few data regarding the accuracy of Hologic QDR-1000W dual-energy X-ray absorptiometry for the measurement of body composition. In two studies, one in an in vitro experimental system using oil and water mixtures and the other in samples of pork meat, the effect of depth and tissue thickness on the measured composition was assessed. In the latter study the measured fat mass was compared with that measured by direct analysis. 2. All data indicated a trend in the measured fat mass with depth, such that more fat was measured at extremes of depth (<10 cm and >25 cm) than at intermediate depths. 3. In samples of meat weighing approximately 55 kg, dual X-ray absorptiometry significantly underestimated the absolute fat mass compared with direct analysis (mean 20.4 ± 1.65%) by 5–8% or 1–4 kg of fat. 4. These findings are of direct relevance to both clinical and research work using this technique to measure body composition, in particular in circumstances in which changes in body composition and/or tissue thickness are anticipated.

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Validation of the Integrative Body Composition Method for Assessing Fat Mass with Dual-energy X-ray Absorptiometry

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000488012.43355.9a ◽

2016 ◽

Vol 48 ◽

pp. 1001-1002

Author(s):

Thomas S. Lyons ◽

Battogtokh Zagdsuren ◽

John C. Jackson ◽

James M. Green

Keyword(s):

Body Composition ◽

Fat Mass ◽

Dual Energy ◽

X Ray ◽

Composition Method

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Comparison of Dual-Energy X-Ray Absorptiometry (DXA) versus a Multi-frequency Bioelectrical Impedance (InBody 770) Device for Body Composition Assessment after a 4-Week Hypoenergetic Diet

Journal of Functional Morphology and Kinesiology ◽

10.3390/jfmk4020023 ◽

2019 ◽

Vol 4 (2) ◽

pp. 23 ◽

Cited By ~ 4

Author(s):

Antonio ◽

Kenyon ◽

Ellerbroek ◽

Carson ◽

Burgess ◽

...

Keyword(s):

Body Composition ◽

Energy Intake ◽

Body Fat ◽

Fat Mass ◽

Bioelectrical Impedance ◽

Dual Energy ◽

Fat Free Mass ◽

Percent Body Fat ◽

Men And Women ◽

X Ray

The purpose of this investigation was to compare two different methods of assessing body composition (i.e., a multi-frequency bioelectrical impedance analysis (MF-BIA) and dual-energy x-ray absorptiometry (DXA)) over a four-week treatment period in exercise-trained men and women. Subjects were instructed to reduce their energy intake while maintaining the same exercise regimen for a period of four weeks. Pre and post assessments for body composition (i.e., fat-free mass, fat mass, percent body fat) were determined via the MF-BIA and DXA. On average, subjects reduced their energy intake by ~18 percent. The MF-BIA underestimated fat mass and percentage body fat and overestimated fat-free mass in comparison to the DXA. However, when assessing the change in fat mass, fat-free mass or percent body fat, there were no statistically significant differences between the MF-BIA vs. DXA. Overall, the change in percent body fat using the DXA vs. the MF-BIA was −1.3 ± 0.9 and −1.4 ± 1.8, respectively. Our data suggest that when tracking body composition over a period of four weeks, the MF-BIA may be a viable alternative to the DXA in exercise-trained men and women.

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Body composition techniques and the four-compartment model in children

Journal of Applied Physiology ◽

10.1152/jappl.2000.89.2.613 ◽

2000 ◽

Vol 89 (2) ◽

pp. 613-620 ◽

Cited By ~ 146

Author(s):

David A. Fields ◽

Michael I. Goran

Keyword(s):

Body Composition ◽

Fat Mass ◽

Total Body Water ◽

Compartment Model ◽

Dual Energy ◽

Air Displacement Plethysmography ◽

X Ray ◽

Bod Pod ◽

Hydrostatic Weighing ◽

Total Body

The purpose of this study was to compare the accuracy, precision, and bias of fat mass (FM) as assessed by dual-energy X-ray absorptiometry (DXA), hydrostatic weighing (HW), air-displacement plethysmography (PM) using the BOD POD body composition system and total body water (TBW) against the four-compartment (4C) model in 25 children (11.4 ± 1.4 yr). The regression between FM by the 4C model and by DXA deviated significantly from the line of identity (FM by 4C model = 0.84 × FM by DXA + 0.95 kg; R 2 = 0.95), as did the regression between FM by 4C model and by TBW (FM by 4C model = 0.85 × FM by TBW − 0.89 kg; R 2 = 0.98). The regression between FM by the 4C model and by HW did not significantly deviate from the line of identity (FM by 4C model = 1.09 × FM by HW + 0.94 kg; R 2 = 0.95) and neither did the regression between FM by 4C (using density assessed by PM) and by PM (FM by 4C model = 1.03 × FM by PM + 0.88; R 2 = 0.97). DXA, HW, and TBW all showed a bias in the estimate of FM, but there was no bias for PM. In conclusion, PM was the only technique that could accurately, precisely, and without bias estimate FM in 9- to 14-yr-old children.

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Identification of and Associations among Low, Middle, and High Body Composition Trajectories from Age 5- to 17-Years

Children ◽

10.3390/children7100192 ◽

2020 ◽

Vol 7 (10) ◽

pp. 192

Author(s):

Teresa A. Marshall ◽

Alexandra M. Curtis ◽

Joseph E. Cavanaugh ◽

John J. Warren ◽

Steven M. Levy

Keyword(s):

Body Composition ◽

Body Fat ◽

Fat Mass ◽

Dual Energy ◽

Fat Free Mass ◽

Clinical Settings ◽

Fat Mass Index ◽

X Ray ◽

Body Composition Measure ◽

Dxa Scans

Our objective was to identify sex-specific age 5- to 17-year body composition (body mass index (BMI), % body fat, fat mass index, fat-free mass index) trajectories, compare trajectories assigned using age 5 (AGE5) data to those assigned using all available (ALL) data, and compare BMI assignments to other body composition assignments. Cluster analysis was used to identify low, medium, and high trajectories from body composition measures obtained from dual energy x-ray absorptiometry (DXA) scans at 5, 9, 11, 13, 15, and 17 years in a birth cohort followed longitudinally (n = 469). Moderate agreement was observed for comparisons between AGE5 data and ALL data cluster assignments for each body composition measure. Agreement between cluster assignments for BMI and other body composition measures was stronger using ALL data than using AGE5 data. Our results suggest that BMI, % body fat, fat mass index, and fat free mass index trajectories are established during early childhood, and that BMI is a reasonable predictor of body composition appropriate to track obesity in public health and clinical settings.

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Validation of foot-to-foot bioelectrical impedance analysis with dual-energy X-ray absorptiometry in the assessment of body composition in young children: the EarlyBird cohort

British Journal Of Nutrition ◽

10.1017/bjn20061960 ◽

2006 ◽

Vol 96 (6) ◽

pp. 1163-1168 ◽

Cited By ~ 39

Author(s):

Joanne Hosking ◽

Brad S. Metcalf ◽

Alison N. Jeffery ◽

Linda D. Voss ◽

Terence J. Wilkin

Keyword(s):

Body Composition ◽

Young Children ◽

Fat Mass ◽

Bioelectrical Impedance Analysis ◽

Large Scale ◽

Bioelectrical Impedance ◽

Impedance Analysis ◽

Dual Energy ◽

Fat Free Mass ◽

X Ray

Foot-to-foot bioelectrical impedance analysis (BIA) is simple and non-invasive, making it particularly suitable for use in children. There is insufficient evidence of the validity of foot-to-foot BIA compared with dual-energy X-ray absorptiometry (DEXA) as the criterion method in healthy young children. Our objective was to assess the validity of foot-to-foot BIA against DEXA in a large cohort of healthy young children. Body composition was measured by foot-to-foot BIA and DEXA in 203 children (mean age 8·9 (sd0·3) years). Bland–Altman and simple linear regression analyses were used to determine agreement between methods. BIA overestimated fat-free mass by a mean of 2·4 % in boys and 5·7 % in girls, while fat mass was underestimated by 6·5 % in boys and 10·3 % in girls. The percentage fat recorded by BIA was, accordingly, also lower than by DEXA (boys 4·8 %; girls 12·8 %). In boys, however, there were correlations between the size of the difference between methods and the size of the measure under consideration such that in smaller boys fat-free mass was underestimated (r − 0·57;P < 0·001) while fat mass and percentage fat were overestimated (r0·74 for fat mass;r0·69 for percentage fat; bothP < 0·001) with the reverse in bigger boys. Mean differences between techniques were greater in the girls than in the boys but in boys only, the direction of the differences was dependent upon the size of the child. Therefore, BIA may be useful for large-scale studies but is not interchangeable with DEXA and should be interpreted with caution in individuals.

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Measuring body condition of lizards: a comparison between non-invasive dual-energy X-ray absorptiometry, chemical fat extraction and calculated indices

Frontiers in Zoology ◽

10.1186/s12983-020-00382-w ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Guy Sion ◽

Maggie J. Watson ◽

Amos Bouskila

Keyword(s):

Body Mass ◽

Body Condition ◽

Fat Mass ◽

Dual Energy ◽

The Body ◽

Ecological Studies ◽

Fat Percentage ◽

X Ray ◽

Non Invasive ◽

Fat Extraction

Abstract Background Condition indices (CIs) are used in ecological studies as a way of measuring an individual animal’s health and fitness. Noninvasive CIs are estimations of a relative score of fat content or rely on a ratio of body mass compared to some measure of size, usually a linear dimension such as tarsus or snout-vent length. CIs are generally validated invasively by lethal fat extraction as in a seasonal sample of individuals in a population. Many alternatives to lethal fat extraction are costly or time consuming. As an alternative, dual-energy X-ray absorptiometry (DXA) allows for non-destructive analysis of body composition and enables multiple measurements during an animal’s life time. DXA has never been used for ecological studies in a small, free-ranging lizard before, therefore we calibrated this method against a chemical extraction of fat from a sample of 6 geckos (Israeli fan toed gecko Ptyodactylus guttatus) ranging in body mass between 4.2–11.5 g. We then used this calibrated DXA measurements to determine the best linear measurement calculated CI for this species. Results We found that fat mass measured with DXA was significantly correlated with the mass of chemically extracted fat for specimens more than 4.8 g (N = 5, R2 = 0.995, P < 0.001). Fat percentage regressed with body mass significantly predicted the DXA fat percentage (N = 29, R2adj. = 0.862, p < 0.001). Live wet mass was significantly correlated with predicted fat mass (N = 30, R2 = 0.984, P < 0.001) for specimens more than 4.8 g. Among the five calculated non-invasive CIs that we tested, the best was mass/SVL. Conclusions We recommend that in situations where DXA cannot be used, that the most accurate of the body condition estimators for this species is mass/SVL (snout-vent length) for both sexes.

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Comparison of a GE Lunar DPX-IQ and a Norland XR-26 dual energy X-ray absorptiometry scanner for body composition measurements in pigs – <i>in vivo</i>

Archives Animal Breeding ◽

10.5194/aab-53-162-2010 ◽

2010 ◽

Vol 53 (2) ◽

pp. 162-175 ◽

Cited By ~ 5

Author(s):

D. Lösel ◽

P. Kremer ◽

E. Albrecht ◽

A. M. Scholz

Keyword(s):

Body Composition ◽

Bone Mineral ◽

Performance Testing ◽

Dual Energy ◽

The Body ◽

Fat Percentage ◽

Mineral Density ◽

X Ray ◽

And Performance

Abstract. In the context of future growth and performance testing, this study compares corresponding body composition results measured by two dual energy X-ray absorptiometry systems. To test the capability of each device to detect differences among experimental groups widely varying in body composition, 77 pigs from 6 purebred/crossbred groups were used for the experiment. Each pig was scanned consecutively on a Norland XR-26 and on a GE Lunar DPX-IQ. Coefficients of determination were: R²=0.92 for bone mineral content (BMC), R²=0.90 for bone mineral density (BMD), R²=0.94 for lean mass (LEAN), R²=0.92 for fat mass (FAT), R²=0.88 for lean percentage (%LEAN) and fat percentage (%FAT). However, Norland yielded larger values for %FAT and smaller values for %LEAN, BMC, and BMD than Lunar (P<0.001) with the extent of deviation depending on the specific trait and on the breeding group. The deviation in BMC was greater than the deviation in BMD, suggesting different bone detecting algorithms. Both systems revealed similar differences among the breeding groups, and ranked them in the same order based on numerical values. Differences in calibration, bone detection, and software algorithms, however, require a prior crosscalibration to make the body composition data from both systems directly comparable. Finally, they can be used across research centres for the determination of relative and absolute body composition differences among animal groups and individuals.

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Validity of the 4-compartment model using dual energy X-ray absorptiometry-derived body volume in overweight individuals

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2017-0804 ◽

2018 ◽

Vol 43 (7) ◽

pp. 742-746 ◽

Cited By ~ 10

Author(s):

Malia N.M. Blue ◽

Katie R. Hirsch ◽

Eric T. Trexler ◽

Abbie E. Smith-Ryan

Keyword(s):

Body Composition ◽

Total Error ◽

Bioelectrical Impedance ◽

Compartment Model ◽

Dual Energy ◽

Body Volume ◽

Fat Percentage ◽

X Ray ◽

Total Body ◽

Mean Differences

The purpose of the present study was to assess the validity of dual-energy X-ray absorptiometry (DXA) to estimate body volume (BV) for use in a 4-compartment (4C) body composition model in an overweight/obese population. Body composition of 61 overweight/obese adults (age: 37.3 ± 10.0 years; height: 170.2 ± 9.5 cm; body mass: 97.1 ± 17.4 kg) was measured by 2 methods: a criterion 4C model and a DXA-derived BV 4C model. For both models, bioelectrical impedance spectroscopy was used to estimate total body water; total body bone mineral content was measured by a full-body DXA scan. For the criterion 4C model, BV was derived from air displacement plethysmography; for the DXA-4C model, BV was derived from previously published coefficients. Total error (TE) and standard error of the estimate (SEE) values for BV (TE = 1.11 L; SEE = 0.01 L) and body fat percentage (%fat) (TE = 2.92%; SEE = 0.32%) represented good to very good agreement between models. The DXA-derived measures of body composition (BV: 96.6 ± 18.1 L; %fat: 39.5% ± 8.1%; fat mass: 38.5 ± 11.9 kg), were significantly greater (p < 0.001) than 4C criterion measures (BV: 95.7 ± 17.6 L; %fat: 37.0% ± 7.6%; FM: 36.0 ± 10.8 kg) with the exception of lean mass, which was significantly lower (p < 0.001; DXA-4C: 58.2 ± 11.2 kg; criterion 4C: 60.7 ± 12.0 kg). Although small statistically significant mean differences were observed, TE and SEE results support the use of the DXA-4C method, which requires less time and equipment, for valid estimates of body composition in overweight/obese individuals.

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Measuring body condition of lizards: a comparison between non-invasive dual-energy X-ray absorptiometry, chemical fat extraction and calculated indices

10.21203/rs.3.rs-47832/v1 ◽

2020 ◽

Author(s):

Guy Sion ◽

Maggie J. Watson ◽

Amos Bouskila

Keyword(s):

Body Mass ◽

Body Condition ◽

Fat Mass ◽

Dual Energy ◽

The Body ◽

Ecological Studies ◽

Fat Percentage ◽

X Ray ◽

Non Invasive ◽

Fat Extraction

Abstract Background Condition indices (CIs) are used in ecological studies as a way of measuring an individual animal’s health and fitness. Noninvasive CIs are estimations of a relative score of fat content or rely on a ratio of body mass compared to some measure of size, usually a linear dimension such as tarsus or snout-vent length. CIs are generally measured invasively by lethal fat extraction as in a seasonal sample of individuals in a population. Many alternatives to lethal fat extraction are costly or time consuming. As an alternative, dual-energy X-ray absorptiometry (DXA) allows for non-destructive analysis of body composition and enables multiple measurements during an animal's life time. DXA has never been used for ecological studies in a small, free-ranging lizard before, therefore we calibrated this method against a chemical extraction of fat from a sample of 6 geckos (Israeli fan toed gecko Ptyodactylus guttatus) ranging in body mass between 4.2–11.5 g. Results We found that fat mass measured with DXA was significantly correlated with the mass of chemically extracted fat for specimens more than 4.8 g (N = 5, R2 = 0.995, P < 0.001). Fat percentage regressed with body mass significantly predicted the DXA fat percentage (N = 30, R2adj.=0.875, P < 0.001). Live wet mass was significantly correlated with calculated fat mass (N = 30, R2 = 0.984, P < 0.001) for specimens more than 4.8 g. Among the other calculated non-invasive CIs that we tested, the best was mass/SVL (provide N, correlation coeff and p value). Conclusions We recommend that in situations where DXA cannot be used, that the most accurate of the body condition estimators for both males and females in this species is mass/SVL (snout-vent length) for both sexes.

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