Abstract
ObjectivesConcerns regarding marked differences in the weights and body composition of young rugby players competing within the same age groups have led to the suggestion of alternative models for grouping young players. The aims of this study were (1) to compare variance in the body size and body composition of schoolboy rugby players (9 to 14 years), across weight- and age-grading models, and (2) to identify morphotypes for the weight model using Hattori’s body composition chart.Materials and MethodsSkinfold thickness measurements were used to assess body fat mass (BF), fat-free mass (FFM), body fat mass index (BFMI), and fat-free mass index (FFMI). Standardized measure of height and weight were taken for all participants. Data were grouped according to the age categories of the French Rugby Federation (U11: Under 11 years, U13: Under 13 years, and U15: Under 15 years), and to the weight categories (W30–44.9; W45–59.9; and W60–79.9) carried out from 25th and 75th weight percentile in each age category. Body mass index status (NW normal-weight versus OW/OB overweight/obese) was considered. Extreme morphotypes are characterized from BFMI and FFMI in the weight-grading model on Hattori’s body composition chart.ResultsThe dispersion of anthropometric characteristics decreased significantly for the weight model, except for height in all groups and BFMI for U13. Among NW, 3, 1.8, and 0% upgraded; 18.2, 68.7, and 45.5% downgraded; among OW, 50, 21.5, and 12.5%; and among OB, 91.3, 83.3, and 74.6% upgraded, respectively, in U11, U13, U15. FFMI/BFMI were correlated in U11 (r = 0.80, p < 0.001), U13 (r = 0.66, p < 0.001), and U15 (r = 0.77, p < 0.001). There was no significant correlation in W45–59.9 and low correlations in W30–44.9 (r = 0.25, p < 0.001) and W60–79.9 (r = 0.29, p < 0.001). Significant grading difference between the centroids (p < 0.05) and the distribution deviates from centroids of BFMI and FFMI (p < 0.0001) were noted between the two models. Thirteen players were located in adipo-slender, twenty-three in adipo-solid, twenty-two in lean-slender, and two located in the lean-solid morphotype in weight model.ConclusionA weight-grading model should be considered to limit mismatches in anthropometric variables. However, variations of body composition also persisted for this model. Hattori’s body composition chart allowed more detailed examination of morphological atypicalities among schoolboy rugby players.
Highlights
In the last decades, the evolution of rugby union has moved toward a significant increase in the physical size among the players
When compared with age groups, the weight-graded strategy resulted in a significant reduction (p < 0.001) in the coefficients of variance for weight, body mass index (BMI), body fat mass index (BFMI), and fat-free mass index (FFMI), but not height (p = 0.21)
Mean values for weight (+4.0 kg/+8.4%, p < 0.001, d = 0.42), height (+1.7 cm/+1.1%, p < 0.05, d = 0.19), BMI (+1.6 kg m−2/+7.9%, p < 0.001, d = 0.51), BFMI (+1.0 kg m−2/+21.3%, p < 0.001, d = 0.48), and FFMI (+0.5 kg m−2/+3.2%, p < 0.001, d = 0.31) were significantly higher in W45–59.9 than in Under 13 years (U13)
Summary
The evolution of rugby union has moved toward a significant increase in the physical size among the players. The trend toward “heavier and taller” players is observed in adolescent rugby players (Sedeaud et al, 2013) This secular change can be explained by a number of factors, including more extensive and competitive advancements in player identification and selection and greater investment in conditioning techniques and resources for junior players, and secular increases in height and weight among the general youth population during the last decades (Bartkowiak et al, 2020). In sports such as rugby, young players can focus on the desire to gain weight during growth, especially as muscle mass, to improve strength, power, and speed performance (Carl et al, 2017). Major differences have been observed in body weight and body composition (Gavarry et al, 2018), maturity (Nutton et al, 2012), and physical qualities of strength and power (McCunn et al, 2017; Perroni et al, 2018) between young players in the same age category during puberty
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