ABSTRACT
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 (rpartial(12) = 0.196), FM (rpartial(12) = -0.013), LM (rpartial(12) = 0.351), BMD (rpartial(12) = 0.168) and BMC (rpartial(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.
Subject(s)
Football , Rugby , Absorptiometry, Photon , Body Composition , Bone Density , Female , Humans , SeasonsABSTRACT
BACKGROUND: Caffeine has been shown to enhance strength, power and endurance, characteristics that underpin performance in rugby. Caffeinated gum has attracted interest as a novel vehicle for delivering caffeine, because absorption of caffeine from gum is quick. Rapid absorption of caffeine may be useful during rugby matches when there is limited time for supplementation such as at half-time or when substitutes enter play. The purpose of this study was to determine whether a low dose of caffeine in gum improves performance in a battery of rugby-specific tests. METHODS: In a double-blind, randomized, placebo-controlled, crossover design, 17 male university-standard rugby players (mass: 85.6 ± 6.3 kg; height: 179.4 ± 6.2 cm; age: 20.4 ± 1.2 years) chewed caffeinated gum (200 mg caffeine) or a placebo gum on two occasions separated by a week. After a standardized warm-up, gum was chewed for 5 min. Subsequently, participants performed three countermovement jumps, followed by an Illinois agility test, 6 × 30 m repeated sprints, and the Yo-Yo IR-2 test; each test was separated by short rest periods. RESULTS: Caffeinated gum enhanced countermovement jump by 3.6% (caffeine: 43.7 ± 7.6 cm vs. placebo: 42.2 ± 6.2 cm; d = 0.22, 95% CI [0.006, 0.432]; p = 0.044). There was a greater resistance to fatigue during the 6 × 30 m repeated sprint test (fatigue index caffeine: 102.2 ± 0.9% vs. placebo: 103.3 ± 1.2%; d = 1.03, 95% CI [0.430, 1.613]; p = 0.001), and performance on the Yo-Yo IR2 was improved by 14.5% (caffeine: 426 ± 105 m, placebo: 372 ± 91 m; d = 0.55, 95% CI [0.130, 0.957]; p = 0.010). Caffeine gum had no significant effect on the Illinois agility test (caffeine 16.22 ± 1.08 s vs. placebo 15.88 ± 1.09 s; d = - 0.31, 95% CI [- 0.855, 0.240]; p = 0.271). CONCLUSIONS: In university-standard rugby players, a low dose of caffeine (200 mg) supplied in chewing gum enhanced performance on the Yo-Yo IR-2 test and the countermovement jump test and reduced fatigue index during repeated sprints. These improvements in a battery of rugby-specific tests may transfer to enhanced performance in rugby matches.