Regional placement of bone mineral mass, fat mass, and lean soft tissue mass in young adult rugby union players

Match-Play Demands and Anthropometric Characteristics of National and International Women's Fifteen-a-side Rugby Union: A Systematic Scoping Review

ABSTRACT

Curtis, C, Mitchell, S, and Russell, M. Match-play demands and anthropometric characteristics of national and international women's, fifteen-a-side rugby union: a systematic scoping review. J Strength Cond Res 37(10): e569-e580, 2023-An increased professionalization within women's 15-a-side rugby union (R15s) has prompted greater sports science support and a need to better understand demands of the sport. Online database (PubMed, MEDLINE, and SPORTDiscus) searches were performed according to the PRISMA Scoping Review protocol. Studies were eligible if match-play demands or anthropometric characteristics of women's R15s players were investigated. After calibration exercises, the lead and senior authors independently quality assessed each study. A total of 1,068 studies were identified; 15 of which met the study criteria. The mean total match-play distance covered was 5,378 ± 626 m (forwards: 5,188 ± 667 m and backs: 5,604 ± 609 m), with first half values exceeding second half (2,922 ± 87 m vs. 2,876 ± 115 m). The mean relative distance (RD) (72.0 m·min -1 ) was greater than their male counterparts (64.2 m·min -1 -68.2 m·min -1 ). Backs were exposed to more severe collisions compared with forwards (6 ± 1 vs. 5 ± 4). Work:rest ratios ranged between 1.0:0.7-1.0:0.9. Regarding anthropometric characteristics, the mean lean and fat mass was reported as 51.9 ± 5.2 kg and 18.6 ± 4.6 kg, respectively. The mean body fat percentage was 24.7 ± 5.4%. The mean bone mineral density and bone mineral content was 1.27 ± 0.04 g·cm -2 and 3.07 ± 0.2 kg, respectively. This scoping review summarizes the current evidence base and key findings relating to the match-play demands and anthropometric characteristics that can be used in practice to inform player welfare and sport science support to women's R15s players at a national and international standard. Numerous gaps in our understanding of how best to develop and optimize performance, physical demands, and anthropometric characteristics of women's R15s players remain.

Season-Long Changes in the Body Composition Profiles of Competitive Female Rugby Union Players Assessed via Dual Energy X-Ray Absorptiometry

Background: Reference data for the body composition values of female athletes are limited to very few sports, with female Rugby Union players having mostly been omitted from such analyses.Methods: Using dual energy X-ray absorptiometry (DXA) scans, this study assessed the body composition profiles (body mass, bone mineral content; BMC, fat mass; FM, lean mass; LM, bone mineral density; BMD) of 15 competitive female Rugby Union players before and after the 2018/19 competitive season. Total competitive match-play minutes were also recorded for each player.Results: Body mass (73.7 ± 9.6 kg vs 74.9 ± 10.2 kg, p ≤ 0.05, d = 0.13) and BMC (3.2 ± 0.4 kg vs 3.3 ± 0.4 kg, p ≤ 0.05, d = 0.15) increased pre- to post-season for all players. Conversely, FM (21.0 ± 8.8 kg), LM (50.7 ± 3.9 kg), and BMD (1.31 ± 0.06 g·cm^-2) were similar between time-points (all p > .05). Accounting for position, body mass (r_partial(12) = 0.196), FM (r_partial(12) = -0.013), LM (r_partial(12) = 0.351), BMD (r_partial(12) = 0.168) and BMC (r_partial(12) = -0.204) showed no correlation (all p > .05) against match-play minutes.Conclusion: The demands of the competitive season influenced specific body composition indices (i.e., body mass, BMC) in female Rugby Union players; a finding which was unrelated to the number of minutes played in matches. While the causes of such differences remain unclear, practitioners should be cognizant of the body composition changes occurring throughout a female Rugby Union competitive season and, where necessary, consider modifying variables associated with adaptation and recovery accordingly.

Body Mass and Body Composition Changes over 7 Years in a Male Professional Rugby Union Team

The purpose of this study was to investigate longitudinal body mass and body composition changes in one professional rugby union team (n=123), (i) according to position [forwards (n=58) versus backs (n=65)], analysis of players with 6 consecutive seasons of DXA scans (n=21) and, (iii) to examine differences by playing status [academy and international], over 7 years. Players [mean age: 26.8 y, body mass index: 28.9+kg.m²] received DXA scans at fourtime points within each year. A modest (but non-significant) increase in mean total mass (0.8 kg) for professional players was reflected by increased lean mass and reduced body fat mass. At all-time points, forwards had a significantly greater total mass, lean mass and body fat percentage compared to backs (p<0.05). Academy players demonstrated increased total and lean mass and decreased body fat percentage over the first 3 years of senior rugby, although this was not significant. Senior and academy international players had greater lean mass and lower body fat percentage (p<0.05) than non-international counterparts. Despite modest increases in total mass; reflected by increased lean mass and reduced fat mass, no significant changes in body mass or body composition, irrespective of playing position were apparent over 7 years.

Body composition differences by age and playing standard in male rugby union and rugby league: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to determine differences in body compositionn between playing standard and age in male rugby union and rugby league athletes. The MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines for design, implementation, and reporting were followed. Studies were required to be in male rugby union or league and have body composition as the primary or secondary outcome. Data was required to be presented separately for positional groups and body composition presented as whole-body. A systematic search was performed in PubMed, Cochrane Library, MEDLINE, SPORTDiscus, and CINHAHL via EBSCOhost. 57 studies were included for meta-analysis. Results highlighted significantly higher fat-free mass in senior elite than senior sub-elite or junior elite athletes for all RU and RL forwards. Small and non-significant differences were found in fat mass between rugby union playing standards and age categories. Rugby league senior elite forwards had less fat mass than junior elite forwards. Practitioners should prioritise training and nutritional strategies that maximise fat-free mass development, especially in junior elite cohorts.

Is an Energy Surplus Required to Maximize Skeletal Muscle Hypertrophy Associated With Resistance Training

Resistance training is commonly prescribed to enhance strength/power qualities and is achieved via improved neuromuscular recruitment, fiber type transition, and/ or skeletal muscle hypertrophy. The rate and amount of muscle hypertrophy associated with resistance training is influenced by a wide array of variables including the training program, plus training experience, gender, genetic predisposition, and nutritional status of the individual. Various dietary interventions have been proposed to influence muscle hypertrophy, including manipulation of protein intake, specific supplement prescription, and creation of an energy surplus. While recent research has provided significant insight into optimization of dietary protein intake and application of evidence based supplements, the specific energy surplus required to facilitate muscle hypertrophy is unknown. However, there is clear evidence of an anabolic stimulus possible from an energy surplus, even independent of resistance training. Common textbook recommendations are often based solely on the assumed energy stored within the tissue being assimilated. Unfortunately, such guidance likely fails to account for other energetically expensive processes associated with muscle hypertrophy, the acute metabolic adjustments that occur in response to an energy surplus, or individual nuances like training experience and energy status of the individual. Given the ambiguous nature of these calculations, it is not surprising to see broad ranging guidance on energy needs. These estimates have never been validated in a resistance training population to confirm the "sweet spot" for an energy surplus that facilitates optimal rates of muscle gain relative to fat mass. This review not only addresses the influence of an energy surplus on resistance training outcomes, but also explores other pertinent issues, including "how much should energy intake be increased," "where should this extra energy come from," and "when should this extra energy be consumed." Several gaps in the literature are identified, with the hope this will stimulate further research interest in this area. Having a broader appreciation of these issues will assist practitioners in the establishment of dietary strategies that facilitate resistance training adaptations while also addressing other important nutrition related issues such as optimization of fuelling and recovery goals. Practical issues like the management of satiety when attempting to increase energy intake are also addressed.

Morphological and Isokinetic Strength Differences: Bilateral and Ipsilateral Variation by Different Sport Activity

BACKGROUND

The purpose of this study was to investigate the morphological and isokinetic strength asymmetry and magnitude in young athletes.

METHODS

One hundred and thirty nine male subjects (soccer, floorball, non-athletes) were measured for proportion of muscle mass between upper extremities (BADΔ) and lower extremities (BLDΔ). Moreover, the peak muscle torque of knee extensors (PTE) and flexors (PTF), ipsilateral (H:Q) and bilateral strength ratio (Q:Q, H:H) were measured.

RESULTS

We found significant differences in observed parameters with respect to different sport activities (F = 13.02, p = 0.00, η p 2 = 0.80). Higher values of BADΔ were observed in the non-active (0.19 ± 0.11 kg) group compared with soccer players (0.10 ± 0.11 kg). We found a lower value of BLDΔ in floorball players (0.32 ± 0.11 kg) compared with soccer players (0.58 ± 0.27 kg) and non-active boys (0.63 ± 0.28 kg). Results revealed significantly higher PTE in soccer players compared with non-active boys and floorball players and higher Q:Q ratio in soccer players (10.99 ± 7.75%) compared with non-active boys (7.47 ± 5.92%).

CONCLUSIONS

This study revealed that there are morphological and strength asymmetries in the observed groups, which may have potential maladaptive effects (e.g. uncompensated overload of extremity) in athletes affected by specific load.

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

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.

Dual-energy X-ray absorptiometry measured regional body composition least significant change: effect of region of interest and gender in athletes

Dual-energy X-ray absorptiometry (DXA) is widely used to evaluate body composition in athletes. Knowledge of measurement precision is essential for monitoring body composition changes over time. This study begins characterizing DXA body composition precision in 60 (30 males and 30 females) Division 1 athletes focusing on gender, regional, and tissue type differences. Two total body scans with repositioning between were performed on the same day. Least significant change (LSC) for the root-mean-square deviation (LSCRMSD) and the percent coefficient of variation (LSC%CV) for total, lean, and fat mass was calculated for 6 regions of interest. The effect of gender, region, tissue type, and mass on the standard deviation (SD) and percent coefficient of variation (%CV) between the 2 scans was evaluated using repeated measures regression analysis. Statistically significant effects of gender, region, tissue type, and mass on SD and %CV were noted. To generalize, a nonlinear positive relationship between LSCRMSD and mass and a nonlinear negative relationship between LSC%CV and mass were observed. In conclusion, DXA body composition LSC varies among genders, regions, tissues, and mass. As such, when evaluating serial body composition in athletes, especially if assessing regional change, knowledge of precision in individuals of similar body size and gender to the population of interest is needed.

Bone mineral density and body composition of South African cricketers

Mechanical loading associated with weight-bearing physical activity has been positively associated with bone mineral density in athletes participating in various sports. The aim of this study was to compare the body composition and bone mineral density of South African male cricketers to controls. Whole body (WB), femoral neck (FN), proximal femur (PF) and lumbar spine (LS) BMD, as well as whole body fat mass (WBFM) and lean mass (WBLM) were measured, using dual-energy X-ray absorptiometry (DXA), on 34 high-performance (senior provincial and national level) cricketers and 23 physically active controls between the ages of 16 and 34 years. Cricketers were significantly younger, taller, and had greater WBLM and WBBMC compared to the controls. LS, PF and FN BMD were higher in the cricketers and controls before and after adjusting for age and height. WBBMD was significantly lower in the spin bowlers compared to the batsmen and fast bowlers, after adjusting for age and height; however, there were no differences at the BMD sites between the groups. Bone mineral density at the lumbar spine and hip sites was significantly greater in the cricketers compared to the controls, suggesting that the mechanical loading associated with cricket is beneficial for bone mineral density.