Preseason Body Composition Adaptations in Elite White and Polynesian Rugby Union Athletes

Abstract

During preseason training, rugby union (RU) athletes endeavor to enhance physical performance characteristics that are aligned with on-field success. Specific physique traits are associated with performance; therefore body composition assessment is routinely undertaken in elite environments. This study aimed to quantify preseason physique changes in elite RU athletes with unique morphology and divergent ethnicity. Twenty-two White and Polynesian professional RU athletes received dual-energy X-ray absorptiometry assessments at the beginning and conclusion of an 11-week preseason. Interactions between on-field playing position and ethnicity in body composition adaptations were explored, and the least significant change model was used to evaluate variations at the individual level. There were no combined interaction effects with the variables position and ethnicity and any body composition measure. After accounting for baseline body composition, Whites gained more lean mass during the preseason than Polynesians (2,425 ± 1,303 g vs. 1,115 ± 1,169 g; F = 5.4, p = .03). Significant main effects of time were found for whole body and all regional measures with fat mass decreasing (F = 31.1-52.0, p < .01), and lean mass increasing (F = 12.0-40.4, p < .01). Seventeen athletes (nine White and eight Polynesian) had a reduction in fat mass, and eight athletes (six White and two Polynesian) increased lean mass. This study describes significant and meaningful physique changes in elite RU athletes during a preseason period. Given the individualized approach applied to athletes in regard to nutrition and conditioning interventions, a similar approach to that used in this study is recommended to assess physique changes in this population.

Physical and Fitness Characteristics of Elite Professional Rugby Union Players

“…These findings support previous studies which demonstrated forwards as having different body composition [ 11 , 12 , 13 , 15 , 16 ] and anthropometric characteristics than backs, including greater strength and absolute power measures, but slower sprint performance and less aerobic fitness [ 6 , 7 , 10 , 33 ]. The characteristic differences between forwards and backs can be attributed to specific positional demands, in which being larger and stronger can assist forwards with winning line outs, scrumming with more force [ 34 ], gaining and retaining possession of the ball at break downs [ 6 ], and absorbing more collisions through tackles and ball carries [ 4 ].…”

“…Players all possess varying levels of physical characteristics, such as anthropometric (height, body mass, skinfold) and body composition (lean mass, fat mass, bone mass) in order to achieve adequate levels of the desired aforementioned fitness qualities and to meet specific positional demands of the sport [ 7 , 8 , 9 ]. Numerous studies have shown that these fitness [ 5 , 7 , 10 ] and physical characteristics [ 11 , 12 , 13 , 14 , 15 , 16 ] vary greatly depending on the player’s position within the team. In general, forwards have a greater body mass and strength emphasis in order to scrummage with more force, tolerate more collisions and gain and retain possession of the ball [ 11 ].…”

“…Although a range of studies have reported the physical [ 11 , 12 , 13 , 14 , 15 , 16 ] and fitness [ 5 , 7 , 10 ] characteristics of professional RU players and have suggested that body composition with optimal amounts of lean mass and fat mass are important for specific fitness qualities, there is limited literature directly examining the relationships between physical and fitness characteristics within professional RU forwards and backs. Furthermore, physical characteristics in the form of body composition have traditionally been collected using skinfold measurements, which are a practical measure due to their reliability, ease of use, low cost, and portability [ 13 , 19 ].…”

“…Furthermore, physical characteristics in the form of body composition have traditionally been collected using skinfold measurements, which are a practical measure due to their reliability, ease of use, low cost, and portability [ 13 , 19 ]. However, a method that has gained popularity for body composition analysis within professional athletes [ 20 , 21 ] and specifically within professional rugby players [ 11 , 12 , 13 , 14 , 15 , 16 , 19 , 22 , 23 ] is the use of dual-energy X-ray absorptiometry (DXA).…”

Same-Day Vs Consecutive-Day Precision Error of Dual-Energy X-Ray Absorptiometry for Interpreting Body Composition Change in Resistance-Trained Athletes

“…week period [24]. Furthermore, these findings are similar to those reported for bone mineral density, in that same-day precision underestimated true variability, which could potentially result in an incorrect interpretation of longitudinal change [25].…”