Differences in visceral adipose tissue and biochemical cardiometabolic risk markers in elite rugby union athletes of Caucasian and Polynesian descent

Polynesian individuals are leaner with greater musculature than Caucasians of an equivalent size, and this genetically different morphology provides a physique that is often compatible with success in a number of sports, including rugby union. Evidence indicates that Polynesians have greater stores of absolute and relative abdominal fat mass and this is known to confer cardiometabolic risk. The aims of this study were to (1) explore the relationship between ethnicity, visceral adipose tissue (VAT), and cardiometabolic disease risk markers in elite Caucasian and Polynesian rugby union athletes, and (2) assess the impact of a pre-season training programme on these markers. Twenty-two professional rugby union athletes of Caucasian (n = 11) and Polynesian (n = 11) descent underwent physique assessment via surface anthropometry, dual-energy X-ray absorptiometry, and magnetic resonance imaging before and after an 11-week pre-season. A fasted blood test was undertaken at both time points. Compared to Caucasians, at baseline Polynesians displayed significantly higher VAT (771 ± 609 cm3 vs 424 ± 235 cm3; p = 0.043), triglycerides (1.0 ± 0.9 mmol/L vs 0.6 ± 0.2 mmol/L; p = 0.050), and low-density lipoprotein cholesterol (3.1 ± 0.9 mmol/L vs 2.3 ± 0.7 mmol/L; p = 0.019). Similar changes were observed in both groups over the pre-season period in VAT and blood biochemical markers. Polynesian rugby union athletes were more likely than Caucasians to exhibit risk factors associated with cardiometabolic disease, such as elevated VAT and unfavourable lipid profiles. Further longitudinal research is required to identify and explain the short- and long-term risk of cardiometabolic disease in athletes of Polynesian descent

Longitudinal changes in body composition assessed using DXA and surface anthropometry show good agreement in elite Rugby Union athletes

Rugby union athletes have divergent body composition based on the demands of their on-field playing position and ethnicity. With an established association between physique traits and positional requirements, body composition assessment is routinely undertaken. Surface anthropometry and dual-energy X-ray absorptiometry (DXA) are the most common assessment techniques utilised, often undertaken synchronously. This study aims to investigate the association between DXA and surface anthropometry when assessing longitudinal changes in fat free mass (FFM) and fat mass (FM) in rugby union athletes. Thirty-nine elite male rugby union athletes (age 25.7 ± 3.1 years; stature 187.6 ± 7.7 cm; mass 104.1 ± 12.2 kg) underwent assessment via DXA and surface anthropometry multiple times over three consecutive international seasons. Changes in the lean mass index (LMI), an empirical measure to assess proportional variation in FFM, showed large agreement with changes in DXA FFM (r=0.54, SEE=1.5%,

Abdominal adiposity distribution in elite rugby union athletes using magnetic resonance imaging

Purpose: This study aimed to assess visceral adipose tissue (VAT), an established marker for cardiometabolic complications, in elite rugby union athletes, with specific consideration given to ethnicity. The ability of dual-energy X-ray absorptiometry (DXA) to estimate VAT in athletic populations compared to the criterion magnetic resonance imaging (MRI) was also explored. Methods: Thirty elite male rugby union athletes (age 23.9 ± 4.0 years; stature 186.7 ± 7.0\ua0cm; mass 101.9 ± 11.2\ua0kg) underwent assessment via DXA for body composition, and MRI for abdominal adiposity, at the start of the pre-season training period. Participants were ascribed a specific ethnicity when three or more of their grandparents were of either Caucasian or Polynesian descent. Results: MRI VAT did not differ between ethnicities (Caucasian 92.7 ± 26.7\ua0cm; Polynesian 86 ± 27.3\ua0cm; p = 0.52); however, there was a trend for forwards (96.7 ± 25.0\ua0cm) to have higher VAT than backs (81.7 ± 27.3\ua0cm; p = 0.13) which provides an area of interest for researchers. Thirty-seven percent of athletes (eight forwards, three backs) were found to have VAT > 100\ua0cm, a threshold for increased cardiometabolic risk within the general population. Bland–Altman analysis indicated that DXA VAT underestimated MRI VAT by ~ 25\ua0cm, with relatively wide limits of agreement (− 24.0 to 75.6\ua0cm). Conclusions: Given the size of rugby union athletes, and the association between elevated VAT and cardiometabolic complications in “supersized” athletes from other sports, further investigation into VAT and other markers of cardiometabolic disease in rugby union populations is warranted. Further, DXA was found to underestimate VAT compared to the criterion MRI in this athletic population

Single and combined effects of beetroot juice and caffeine supplementation on cycling time trial performance

Both caffeine and beetroot juice have ergogenic effects on endurance cycling performance. We investigated whether there is an additive effect of these supplements on the performance of a cycling time trial (TT) simulating the 2012 London Olympic Games course. Twelve male and 12 female competitive cyclists each completed 4 experimental trials in a double-blind Latin square design. Trials were undertaken with a caffeinated gum (CAFF) (3 mg·kg−1 body mass (BM), 40 min prior to the TT), concentrated beetroot juice supplementation (BJ) (8.4 mmol of nitrate (NO3–), 2 h prior to the TT), caffeine plus beetroot juice (CAFF+BJ), or a control (CONT). Subjects completed the TT (females: 29.35 km; males: 43.83 km) on a laboratory cycle ergometer under conditions of best practice nutrition: following a carbohydrate-rich pre-event meal, with the ingestion of a carbohydrate–electrolyte drink and regular oral carbohydrate contact during the TT. Compared with CONT, power output was significantly enhanced after CAFF+BJ and CAFF (3.0% and 3.9%, respectively, p < 0.01). There was no effect of BJ supplementation when used alone (–0.4%, p = 0.6 compared with CONT) or when combined with caffeine (–0.9%, p = 0.4 compared with CAFF). We conclude that caffeine (3 mg·kg−1 BM) administered in the form of a caffeinated gum increased cycling TT performance lasting ∼50–60 min by ∼3%–4% in both males and females. Beetroot juice supplementation was not ergogenic under the conditions of this study