Body fat assessment in international elite soccer referees

Soccer referees are a specific group in the sports population that are receiving increasing attention from sports scientists. A lower fat mass percentage (FM%) is a useful parameter to monitor fitness status and aerobic performance, while being able to evaluate it with a simple and quick field-based method can allow a regular assessment. The aim of this study was to provide a specific profile for referees based on morphological and body composition features while comparing the accuracy of different skinfold-based equations in estimating FM% in a cohort of soccer referees. Forty-three elite international soccer referees (age 38.8 ± 3.6 years), who participated in the 2018 Russian World Cup, underwent body composition assessments with skinfold thickness and dual-energy X-ray absorptiometry (DXA). Six equations used to derive FM% from skinfold thickness were compared with DXA measurements. The percentage of body fat estimated using DXA was 18.2 ± 4.1%, whereas skinfold-based FM% assessed from the six formulas ranged between 11.0% ± 1.7% to 15.6% ± 2.4%. Among the six equations considered, the Faulkner's formula showed the highest correlation with FM% estimated by DXA (r = 0.77; R2 = 0.59 p < 0.001). Additionally, a new skinfold-based equation was developed: FM% = 8.386 + (0.478 × iliac crest skinfold) + (0.395 × abdominal skinfold, r = 0.78; R2 = 0.61; standard error of the estimate (SEE) = 2.62 %; p < 0.001). Due to these findings, national and international federations will now be able to perform regular body composition assessments using skinfold measurements. (c) 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)

Optimizing Field Body Fat Percentage Assessment in Professional Soccer Players

Body composition is a determinant of performance in soccer. To estimate the body fat percentage (%BF), dual energy X-ray absorptiometry (DXA) is effective though this method is expensive and not readily accessible. This study examines the validity of widely used field methods based on anthropometric data and bioelectrical impedance analysis (BIA). Participants were 21 male Spanish First Division soccer players aged between 22 and 35 years. In each participant, body fat mass was determined by BIA and using 18 anthropometric equations including skinfold (SKF) measurements. DXA was used as reference. Correlation with DXA measurements was excellent for all equations and separate SKF measurements yet only moderate for BIA. However, only the equation recently developed for use in soccer players based on iliac crest and triceps SKFs showed no significant or standardized differences with DXA-derived %BF and these measurements also had the lowest bias. Our findings suggest that when DXA is not available, the best field method for %BF assessment in footballers is the equation based on iliac crest and triceps SKF. As another good option, we propose the sum of triceps, subscapular, supraspinal, and abdominal SKFs, as this combination also showed good correlation with DXA

Suprailiac or abdominal skinfold thickness measured with a skinfold caliper as a predictor of body density in Japanese adults

金沢大学人間社会研究域人間科学系Measurement of subcutaneous fat thickness with a skinfold caliper is a simple and inexpensive technique for assessment of body composition, but is influenced by the skin site or the obesity level. The resulting measurement errors may influence the prediction accuracy of body density. We therefore aimed to clarify the characteristics of measurement errors with a skinfold caliper and to determine useful measurement sites for the prediction of body density in Japanese adults of wide-ranging age and obesity levels. The present study included 126 Japanese male and 77 female subjects ranging from 21 to 81 years old. They were divided into a "non-obese group" and an "obese group", based on the Japanese criteria of obesity (BMI ≥ 25 kg/m2). Subcutaneous fat thickness was measured at 14 sites with a skinfold caliper and ultrasound. Percent body fat was measured by dual-energy x-ray absorptiometry, and body density was calculated using Brozek\u27s formula. Sex and obesity level differences in the measurement error of skinfolds (ultrasound minus skinfold caliper measurements) were examined by 2 × 2 ANOVA (sex and obesity groups) for each site. The relationship between body density and the systematic error was examined. We developed an accurate prediction equation for body density with smaller measurement and systematic errors. Although measurement errors in skinfold thickness tended to increase with increasing obesity levels, the influence was smaller for the abdominal and suprailiac skinfolds compared with other sites. Measurement of suprailiac or abdominal skinfold thickness is useful to accurately estimate body density in Japanese adults. © 2007 Tohoku University Medical Press

Proposição de equações para a estimativa da gordura corporal em futebolistas

Orientador : Prof. Dr. Raul OsieckiDissertaçao (mestrado) - Universidade Federal do Paraná, Setor de Ciencias Biológicas, Programa de Pós-Graduaçao em Educaçao Física. Defesa: Curitiba, 24/03/2011Inclui referênciasÁrea de concentraçao: Exercício e esporteResumo: O presente estudo teve como objetivo propor equações para predizer o componente de gordura em futebolistas, utilizando medidas antropométricas, tendo como indicador de referência informações associadas aos procedimentos de Absortometria de Raios-X de Dupla Energia (DXA). Participaram do estudo 31 futebolistas profissionais do gênero masculino vinculados a equipes da cidade de Curitiba e apresentavam em média idade 21,48±3,38 anos, massa corporal 79,05±9,49 kg, estatura 181,97±8,11cm e gordura corporal 13,68±4,22 %. Os atletas foram submetidos a avaliação das medidas antropométricas de peso corporal, estatura, circunferências, diâmetros ósseos, espessura de dobras cutâneas e exame de DXA como referência. Para o desenvolvimento das equações para a estimativa da gordura corporal foi realizada a técnica de regressão múltipla (stepwise, forward e backward). A variável dependente foi considerada o percentual de gordura corporal obtido pelo método DXA, e as variáveis independentes foram as combinações e somatórios das variáveis antropométricas que atingiram mais alta correlação com a variável dependente, não menores que 0,70. Além disso, foi verificada a validade de 40 modelos matemáticos já existentes na literatura, utilizando-se dos critérios sugeridos na literatura (LOHMAN, 1992): determinação de correlação múltipla (R), teste &quot;t" pareado, erro constante (EC), erro total (ET), erro padrão de estimativa (EPE). Para o desenvolvimento dos modelos matemáticos, dentre todas as medidas antropométricas coletadas, somente as dobras cutâneas de peito, axilar média, abdômen e coxa foram utilizadas como variáveis independentes por apresentarem correlação superior a 0,70 com a variável dependente (DXA). Todos os 12 modelos matemáticos desenvolvidos no presente estudo, principalmente os modelos lineares, parecem possuir a capacidade de predizer a gordura corporal em futebolistas, porém antes de tal afirmação estas equações precisam ser validadas. Em relação a validação das 40 equações matemáticas já existentes na literatura, apesar de todas terem alcançado correlações fortes ou moderadas com o DXA, somente as equações Durnin & Rahman (1967): 1,161-0,0632 og(BI+TR+SE+SI); Forsyth & Sinning (1973): 10647-0,00162(SE)-0,00144(AB)-0,00077(TR)+0,000071(AX); Durnin & Womersley (1974): 1,1620-0,0630 Log(TR+BI+SI+SE); 1,1631-0,0630 Log(TR+SE+SI+BI); 1,1360-0,0700 Log(SE) e 1,1575-0,0617 Log(TR+SE+SI) e Eston et al (2005): 4,05+0,52(CX)+0,32(SI) atenderam todos os critérios de validação e foram validadas pelo método DXA em relação a população estudada, apresentando valores baixos de EC (entre -0,80 e 0,89); ET (<3,5%) e valores aceitáveis de EPE (<3,5%).Abstract: This study aimed to propose equations to predict body fat component specifically for use in soccer players using anthropometric measurements, with the benchmark information related to procedures of Dual-energy X-ray Absorptiometry (DXA). This study involved 31 male professional footballers who worked in clubs in the city of Curitiba and had average age of 21,48 ± 3,38 years, body mass 79,05 ± 9,49 kg, height 181,97 ± 8,11 and body fat 13,68 ± 4,22%. The athletes were subjected to ana ysis of anthropometric measurements of weight, height, body circumferences, breadths, and skinfolds and DXA test as reference. To develop the equations for estimating body fat was performed multiple regression techniques. The dependent variable was considered the percentage of body fat obtained by DXA method, and the independent variables were the summations and combinations of anthropometric variables that reached the highest correlation with the dependent variable, not less than 0,70. In addition, we verified the validity of 40 mathematical models from the literature, using the criteria suggested by Lohman (1992): determination of multiple correlation (R), t-test paired, constant error (EC), total error (ET), standard error of estimate (EPE). For the development of mathematical models, of all collected anthropometric measurements, only the skinfold chest, midaxillary, abdomen and thigh were used as independent variables because they have more han 0,70 correlation with the dependent variable (DXA). All 12 mathematical models developed in this study, mainly linear models, seem to possess the ability to predict body fat in soccer, but before such a claim these equations need to be validated. Regarding the validation of 40 mathematical equations from the literature, despite all the equations have achieved moderate or strong correlations with DXA, only the equations Durnin & Rahman (1967): 1,161-0,0632 Log(BI+TR+SE+SI); Forsyth & Sinning (1973): 1,10647-0,00162(SE)-0,00144(AB)-0,00077(TR)+0,000071(AX); Durnin & Womersley (1974): 1,1620-0,0630 Log(TR+BI+SI+SE); 1,1631-0,0630 Log(TR+SE+SI+BI); 1,1360-0,0700 Log(SE); 1,1575-0,0617 Log(TR+SE+SI) and Eston et al (2005): 4,05+0,52(CX)+0,32(SI) met all criteria for validation and method were validated by DXA in relation to population, with low values of EC (between -0,80 and 0,89), TE (<3,5%) and acceptable values of EPE (<3,5%)

Modelação do sucesso : o rendimento do andebolista português

Doutoramento em Motricidade Humana na especialidade de Ciências do DesportoO presente trabalho teve por objectivo analizar variáveis morfológicas, fisiológicas, psicológicas, técnico-tácticas e biossociais como predictoras de sucesso/rendimento em atletas de andebol do sexo masculino (n = 230, idades, 23.54 ± 5.24 anos). Efectuaram-se trabalhos complementares que suportam as opções metodológicas adoptadas nos cinco estudos principais. Estes cinco estudos tiveram como objectivos estudar o poder discriminante das variáveis morfológicas (Estudo I – Capítulo III), fisiológicas (Estudo II – Capítulo IV), psicológicas (Estudo III – Capítulo V) e biossociais (Estudo IV – Capítulo VI) face a atletas de andebol de níveis diferenciados e, quando oportuno, a atletas de andebol de diferentes posições de jogo. O Estudo V (Capítulo VII) visou a construção dum modelo estatístico que permite predizer o sucesso de atletas do andebol. Os principais resultados revelam que no andebol, a participação individual parece ser optimizada quando estão presentes (individualmente) um conjunto de características morfológicas (Capítulo III), fisiológicas (Capítulo IV), psicológicas (Capítulo V) e biossociais (Capítulo VI), sendo evidente a relação entre cada uma destas famílias de variáveis com o nível competitivo e com posição de jogo dos atletas. Em complemento, o conhecimento produzido e aglutinado no Estudo V (Capítulo VII), possibilitou a construção de dois modelos de regressão em que a probabilidade de sucesso dos atletas de andebol pode ser determinada através de uma abordagem científica interdisciplinar: (i) modelo de atleta de andebol (G2 (7) = 123.179, P <0.001; ROC c = 0.948, P <0,001) e (ii) modelo do atleta de campo de andebol (G2 (7) = 105.117, P <0.001; ROC c = 0.970, P <0.001). Em conclusão, esperamos que os modelos apresentados possam ser utilizados para seleccionar praticantes de andebol com elevado potencial de rendimento, de forma económicamente vantajosa e metodológicamente simples.This study aimed to analyze morphological, physiological, psychological, technical-tactical and biosocial variables as predictors of success / performance of male handball athletes (n = 230, ages, 23:54 ± 5:24 years). There have been written some complementary studies that support the methodological choices adopted in the five major studies. These five studies had as objective to study the discriminating power of morphological (Study I - Part III), physiological (Study II - Chapter IV), psychological (Study III - Chapter V) and biosocial (Study IV - Chapter VI) variables when comparing handball athletes of different levels and, when appropriate, when comparing handball athletes that play in different positions. Study V (Chapter VII) aimed to develop a statistical model that can predict the success of handball players. The main results show that in handball, individual participation seems to be optimal when there are present (individually) a set of morphological characteristics (Chapter III), physiological (Chapter IV), psychological (Chapter V) and biosocial (Chapter VI), being evident the relationship between of each family of variables and the competitive level and the playing position of the handball athletes. In addition, the knowledge produced and gathered in Study V (Chapter VII) maked possible the construction of two regression models where the probability of success of handball athletes can be determined through an scientific multidisciplinary approach: (i) model of the handball athlete (G2 (7) = 123 179, P <0.001; ROC c = 0.948, P <0.001) and (ii) model of the field handball athlete (G2 (7) = 105 117, P <0.001; ROC c = 0.970, P <0.001). In conclusion, we expect that these models can be used to select handball practitioners with high potential level of performance, in an economically advantageous way and though a simple methodology

Exercise Evaluation and Prescription

This is a reprint of articles from the Special Issue published online in the open access journal Journal of Functional Morphology and Kinesiology (ISSN 2411-5142) available at https://www.mdpi.com/journal/jfmk/special_issues/Exercise_Evaluatio

Development of a sport specific anthropometric calibration model\ud to estimate whole body density of professional football players

There are currently no calibration models that allow whole body density in professional\ud footballers to be estimated. As such, there is a need to develop practical calibration\ud models in order to make sound body composition judgements. The aim of this thesis is\ud threefold. Firstly, to examine the measurement reliability of a range of anthropometric\ud measures, residual lung volume, air displacement plethysmography and hydrostatic\ud weighing. Secondly, to establish reliability and precision of body composition \ud measures used within existing calibration models which estimate whole body density\ud from the criterion of hydrostatic\ud weighing. Thirdly, to develop and cross-validate new calibration\ud models for professional footballers.\ud Further details are given in the full abstract above