This study primarily aimed to quantify and compare iron status in professional female athletes and nonathletes. Furthermore, this study also aimed to identify differences in iron status according to sporting discipline and explore the relationship between ferritin concentration and weekly training volume in professional athletes. A total of 152 participants were included in this study, including 85 athletes who were members of senior teams (handball, n = 24; volleyball, n = 36; soccer, n = 19; and judo, n = 6) involved at the highest level of competition and 67 nonathletes. A significantly greater proportion (p = .05) of athletes (27%) demonstrated iron-deficient erythropoiesis (IDE) compared with nonathletes (13%). There were nonsignificant differences (p > .05) in the prevalence of iron deficiency (ID; 49% vs. 46%) and iron deficiency anemia (IDA; 2% vs. 4%) between athletes and nonathletes. Similarly, the prevalence of ID, IDE, and IDA was not significantly different between sports (p > .05). Furthermore, training volume was negatively correlated with ferritin concentration in athletes (r: −.464, moderate, p < .001). Professional female athletes are at a heightened risk of IDE compared with nonathletes; therefore, they should be periodically screened for ID to reduce the deleterious effects on training and performance. The similar prevalence of ID, IDE, and IDA found across athletes competing in different sports suggests that overlaps exist between handball, volleyball, soccer, and judo athletes regarding risk of disturbance in iron metabolism.
Nenad Ponorac, Mira Popović, Dea Karaba-Jakovljević, Zorislava Bajić, Aaron Scanlan, Emilija Stojanović and Dragan Radovanović
Aaron T. Scanlan, Vincent J. Dalbo, Daniele Conte, Emilija Stojanović, Nenad Stojiljković, Ratko Stanković, Vladimir Antić and Zoran Milanović
Purpose: To examine the effect of caffeine supplementation on dribbling speed in elite female and male basketball players. Methods: A double-blind, counterbalanced, randomized, crossover design was used. Elite basketball players (N = 21; 10 female, 11 male; age 18.3 [3.3] y) completed placebo (3 mg·kg−1 of body mass of dextrose) and caffeine (3 mg·kg−1 of body mass) trials 1 wk apart during the in-season phase. During each trial, players completed 20-m linear sprints with and without dribbling a basketball. Performance times were recorded at 5-, 10-, and 20-m splits. Dribbling speed was measured using traditional (total performance time) and novel (dribble deficit) methods. Dribble deficit isolates the added time taken to complete a task when dribbling compared with a nondribbling version of the same task. Comparisons between placebo and caffeine conditions were conducted at group and individual levels. Results: Nonsignificant (P > .05), trivial to small (effect size = 0.04–0.42) differences in dribbling speed were observed between conditions. The majority (20 out of 21) of players were classified as nonresponders to caffeine, with 1 player identified as a negative responder using dribble-deficit measures. Conclusions: Results indicate that caffeine offers no ergogenic benefit to dribbling speed in elite basketball players. The negative response to caffeine in 1 player indicates that caffeine supplementation may be detrimental to dribbling speed in specific cases and emphasizes the need for individualized analyses in nutrition-based sport-science research.