A cross-sectional study assessing the contributions of body fat mass and fat-free mass to body mass index scores in male youth rugby players

Background. In some sports such as rugby, a large body size is an advantage, and the desire to gain weight can bring young players to become overweight or obese. The aim of this study was to evaluate the prevalence of overweight and obesity and the contribution of body fat mass index (BFMI) and fat-free mass index (FFMI) to body mass index (BMI) changes among young male rugby players (15-a-side rugby). Methods. The criteria of the International Obesity Task Force were used to define overweight and obesity from BMI. The method of skinfold thickness was used to assess percentage of body fat (%BF), BFMI, and FFMI. Excess body fat was defined by using BFMI and %BF above the 75th percentile. Data were grouped according to the age categories of the French Rugby Federation (U11, under 11 years; U13, under 13 years; U15, under 15 years) and to BMI status (NW normal-weight versus OW/OB overweight/obese). Results. Overall, 32.8% of the young players were overweight, and 13.8% were obese. However, 53% of young players classified as obese and overweight by BMI had an excess body fat by using BFMI above the 75th percentile. FFMI increased significantly between U11 and U13 in both groups, without significant change in BMI and BFMI. Both groups had similar significant gains in BMI and FFMI between U13 and U15, while BFMI only increased significantly in OW/OB (+ 18.5%). The strong correlations between BMI and %BF were systematically lower than those between BMI and BFMI. FFMI was strongly or moderately associated with BFMI. Conclusions. Chart analysis of BFMI and FFMI could be used to distinguish changes in body composition across age categories in young male rugby players classified as normal-weight, overweight, and obese by BMI

Conviviality and Parallax in David Olusoga’s Black and British: A Forgotten History

Through examining the BBC television series, Black and British: A Forgotten History, written and presented by the historian David Olusoga, and in extending Paul Gilroy’s assertion that the everyday, banality of living with difference is now an ordinary part of British life, this article considers how Olusoga’s historicization of the black British experience reflects a convivial rendering of UK multiculture. In particular, when used alongside Žižek’s notion of parallax, it is argued that understandings of convivial culture can be supported by a historical importance that deliberately ‘shocks’ and, subsequently dislodges, popular interpretations of the UK’s ‘white past’. Notably, it is parallax which puts antagonism, strangeness and ambivalence at the heart of contemporary depictions of convivial Britain, with the UK’s cultural differences located in the ‘gaps’ and tensions which characterize both its past and present. These differences should not be feared but, as a characteristic part of our convivial culture, should be supplemented with historical analyses that highlight but, also, undermine, the significance of cultural differences in the present. Consequently, it is suggested that if the spontaneity of conviviality is to encourage openness, then, understandings of multiculturalism need to go beyond reification in order to challenge our understandings of the past. Here, examples of ‘alterity’ are neither ‘new’ nor ‘contemporary’ but, instead, constitute a fundamental part of the nation’s history: of the ‘gap’ made visible in transiting past and present

Surpoids chez le jeune joueur de rugby : indicateurs diagnostiques

Our thesis work consists first to estimating the prevalence of overweight in young french rugby players from the BMI, according to IOTF criteria. Since the body mass index does not allow any indication of body composition, the contribution of body fat mass and fat-free mass to BMI in different age categories during the puberty period was assessed by using the body fat mass (BFMI) and fat-free mass (FFMI) indexes proposed by VanItallie (1990). The multidimensional Hattori’s body composition chart (1991) makes it possible to assess excess body fat, and to characterize the morphotype of young players, distinguishing normal-weight players from overweight or obese players. The second objective was to analyze the contributions body fat mass and fat-free mass to excess body size, in overweight and obese young rugby players during the puberty period, and ultimately to reconsider the prevalence of overweight in this population. The third objective was to compare the anthropometric characteristics of a weight-grading model with the age-grading model, taking into account BMI status and body composition. Finally, the last objective was to offer coaches/sports staff a diagnostic device based on simple anthropometric indicators (measurement of circumferences), in order to detect overweight and to predict other atypicalities requiring appropriate care.Body composition was assessed by the skinfold method in 738 young players aged 9 to 14 years registered in clubs (Ligue du Sud de rugby), distributed according to their chronological age category: U11, U13, U15.According to the IOTF criteria, the prevalence of overweight is estimated at nearly 47%. However, 53% of young players classified as obese and overweight by BMI had an excess body fat by using BFMI above the 75th percentile. Moreover, the average contribution of fat-free mass to excess bodysize was high (44.3 %). Thus, the average overestimation of the prevalence of overweight is estimated at nearly 20 %. Although overweight/obese players had higher BFMI (range: + 2.9–3.7 kg.m−2) than normal-weight in the present study, they also had higher FFMI (range: + 2.4–2.7 kg.m−2). It is important to mention that the majority of obese rugby players (from 66 to 100%) were in the highest tertile for BFMI and FFMI. So, chart analysis of BFMI and FFMI according to the 25–75th percentiledistribution may be helpful to determine the contribution of body fat mass and fat-free mass to BMIand to avoid misclassification. The weight-grading strategy appears effective in terms of limitingmismatches in these variables among schoolboy rugby players and the identity of the category has been in part preserved. However, atypicalities remained (10 %), especially concerning extreme morphotypes. Morphotypes of young rugby players can be identified from predictive anthropometricequations of BFMI and FFMI by the circumference method, in particular in order to classify playerswithin their home group.In conclusion, Hattori’s body composition chart facilitates better identification of overweight young players and those with low muscle mass, as well as the detection of atypical morphotypes requiring appropriate management. Simple circumference measurements are likely to predict these different morphotypes, and could thus be carried out routinely by coaches/sports staff a prophylactic and performance-enhancing strategy.Notre travail de thèse consiste en premier lieu à estimer la prévalence du surpoids chez le jeune joueur de rugby français à partir de l’IMC, selon les critères IOTF. L’indice de masse corporelle ne permettant pas d’avoir d’indication sur la composition corporelle, la contribution des tissus maigre et gras dans les changements de l’IMC dans différentes catégories d’âge au cours de la période pubertaire, est évaluée à l’aide des indices de masse grasse (IMG) et de masse maigre (IMM) proposés par VanItallie (1990). Le modèle graphique descriptif multidimensionnel développé par Hattori (1991) permet d’évaluer l’excès de masse grasse, et de caractériser le morphotype des jeunes joueurs, en distinguant les joueurs de poids normal des joueurs en surpoids ou obèses. Le deuxième objectif est d’analyser la contribution des tissus maigre et gras dans l’excès de corpulence, chez des jeunes joueurs de rugby en surpoids et obèses au cours de la période pubertaire, et de reconsidérer, in fine, la prévalence du surpoids de cette même population. Le troisième objectif est de comparer la méthode de la catégorisation par le poids avec celle de la catégorisation par l’âge, en prenant en compte le niveau de corpulence et la composition corporelle. Enfin, le dernier objectif est de proposer à l’encadrement sportif un dispositif diagnostique basé sur des indicateurs anthropométriques simples (mesure des circonférences), susceptible de dépister une surcharge pondérale avérée, et de prédire d’autres atypicités nécessitant une attention toute particulière. La composition corporelle est évaluée par la méthode des plis cutanés chez 738 jeunes joueurs de 9 à 14 ans inscrits en club (Ligue du Sud de rugby), répartis selon leur catégorie d’âge chronologique : U11, U13, U15. Selon les critères IOTF, la prévalence du surpoids est estimée à près de 47 %. Cependant, 53% des jeunes joueurs classés comme obèses et en surpoids selon l'IMC présentent un excès de graisse corporelle en utilisant un IMG supérieur au 75ème percentile. De plus, la contribution moyenne du tissu maigre dans l’excès de corpulence est importante (44,3 %). Ainsi, la surestimation moyenne de la prévalence du surpoids est estimée à près de 20 %. Bien que les joueurs en surpoids/obèses aient un IMG plus élevé (étendue : + 2,9–3,7 kg.m−2) que ceux de poids normal dans la présente étude, ils avaient également un IMM plus élevé (étendue : + 2,4–2,7 kg.m−2). Il est important de mentionner que la majorité des joueurs de rugby obèses (66 à 100 %) étaient dans le tertile le plus élevé pour l’IMG et l’IMM. Ainsi, l'analyse graphique de l’IMG et l’IMM selon les 25ème et 75ème percentile de la distribution peut être utile pour déterminer la contribution des masses grasse et maigre à l'IMC et pour éviter une mauvaise classification. La stratégie de catégorisation par le poids semble être efficace pour limiter la dispersion des variables de composition corporelle entre les jeunes joueurs de rugby, tout en préservant en partie l’identité de la catégorie d’âge. Cependant, des atypicités morphologiques subsistent, notamment des morphotypes extrêmes (10 %). Les morphotypes des jeunes joueurs de rugby peuvent être identifiés à partir d’équations anthropométriques prédictives d’IMG et d’IMM par la méthode des circonférences, notamment afin de « classer » les joueurs à l’intérieur de leur groupe d’appartenance.En conclusion, la représentation graphique d’Hattori facilite l’identification des jeunes joueurs en surpoids et de faible masse musculaire, ainsi que la détection de morphotypes atypiques nécessitant une prise en charge adaptée. De simples mesures de circonférences sont susceptibles de prédire ces différents morphotypes, et pourraient être ainsi réalisées en routine par l’encadrement sportif dans une stratégie prophylactique et d’amélioration des performances