International Association of Athletics Federations Consensus Statement 2019: Nutrition for Athletics.

The International Association of Athletics Federations recognizes the importance of nutritional practices in optimizing an Athlete's well-being and performance. Although Athletics encompasses a diverse range of track-and-field events with different performance determinants, there are common goals around nutritional support for adaptation to training, optimal performance for key events, and reducing the risk of injury and illness. Periodized guidelines can be provided for the appropriate type, amount, and timing of intake of food and fluids to promote optimal health and performance across different scenarios of training and competition. Some Athletes are at risk of relative energy deficiency in sport arising from a mismatch between energy intake and exercise energy expenditure. Competition nutrition strategies may involve pre-event, within-event, and between-event eating to address requirements for carbohydrate and fluid replacement. Although a "food first" policy should underpin an Athlete's nutrition plan, there may be occasions for the judicious use of medical supplements to address nutrient deficiencies or sports foods that help the athlete to meet nutritional goals when it is impractical to eat food. Evidence-based supplements include caffeine, bicarbonate, beta-alanine, nitrate, and creatine; however, their value is specific to the characteristics of the event. Special considerations are needed for travel, challenging environments (e.g., heat and altitude); special populations (e.g., females, young and masters athletes); and restricted dietary choice (e.g., vegetarian). Ideally, each Athlete should develop a personalized, periodized, and practical nutrition plan via collaboration with their coach and accredited sports nutrition experts, to optimize their performance.

Four weeks of IV iron supplementation reduces perceived fatigue and mood disturbance in distance runners.

PURPOSE: To determine the effect of intravenous iron supplementation on performance, fatigue and overall mood in runners without clinical iron deficiency. METHODS: Fourteen distance runners with serum ferritin 30-100 µg · L(-1) were randomly assigned to receive three blinded injections of intravenous ferric-carboxymaltose (2 ml, 100 mg, IRON) or normal saline (PLACEBO) over four weeks (weeks 0, 2, 4). Athletes performed a 3,000 m time trial and 10 × 400 m monitored training session on consecutive days at week 0 and again following each injection. Hemoglobin mass (Hbmass) was assessed via carbon monoxide rebreathing at weeks 0 and 6. Fatigue and mood were determined bi-weekly until week 6 via Total Fatigue Score (TFS) and Total Mood Disturbance (TMD) using the Brief Fatigue Inventory and Brunel Mood Scale. Data were analyzed using magnitude-based inferences, based on the unequal variances t-statistic and Cohen's Effect sizes (ES). RESULTS: Serum ferritin increased in IRON only (Week 0: 62.8 ± 21.9, Week 4: 128.1 ± 46.6 µg · L(-1); p = 0.002) and remained elevated two weeks after the final injection (127.0 ± 66.3 µg · L(-1), p = 0.01), without significant changes in Hbmass. Supplementation had a moderate effect on TMD of IRON (ES -0.77) with scores at week 6 lower than PLACEBO (ES -1.58, p = 0.02). Similarly, at week 6, TFS was significantly improved in IRON vs. PLACEBO (ES -1.54, p = 0.05). There were no significant improvements in 3,000 m time in either group (Week 0 vs. Week 4; Iron: 625.6 ± 55.5 s vs. 625.4 ± 52.7 s; PLACEBO: 624.8 ± 47.2 s vs. 639.1 ± 59.7 s); but IRON reduced their average time for the 10 × 400 m training session at week 2 (Week 0: 78.0 ± 6.6 s, Week 2: 77.2 ± 6.3; ES-0.20, p = 0.004). CONCLUSION: During 6 weeks of training, intravenous iron supplementation improved perceived fatigue and mood of trained athletes with no clinical iron deficiency, without concurrent improvements in oxygen transport capacity or performance.

Intravenous iron supplementation in distance runners with low or suboptimal ferritin.

PURPOSE: Iron deficiency is prevalent in distance runners and may impair endurance performance. The current practice of oral supplementation is slow and often not well tolerated. The aim of this study was to assess the efficacy of intravenous (IV) iron supplementation (ferric carboxymaltose) compared with oral supplementation (ferrous sulfate) on iron status, hemoglobin mass (Hbmass), and physiological indices of running performance in distance runners. METHODS: Twenty-seven highly trained distance runners with low (LOW) (ferritin <35 µg·L(-1) and transferrin saturation <20%, or ferritin <15 µg·L(-1)) or suboptimal (SUB) iron status (ferritin <65 µg·L(-1)) were supplemented with either IV iron (Ferinject®) or oral (ORAL) supplements (Ferrogradumet) for 6 wk. Iron status and Hbmass were assessed before supplementation and at 1, 2, 4, 6, and 8 wk in the four groups (IV LOW, IV SUB, ORAL LOW, and ORAL SUB). In addition, athletes completed a treadmill running test for running economy, lactate threshold, and V˙O2max before and after supplementation. RESULTS: Both forms of supplementation substantially increased ferritin levels in all four groups. IV supplementation resulted in higher ferritin in both IV groups compared with both ORAL groups from week 1 onward. Hemoglobin concentration did not change substantially in any group. Hbmass increased in IV LOW (mean = +4.9%, 90% confidence interval [CI] = 1.1%-8.9%) and was accompanied by an increase in V˙O2max (mean = +3.3%, 90% CI = 0.4%-6.3%) and run time to exhaustion (mean = +9.3%, 90% CI = 0.9%-18.3%. CONCLUSIONS: IV supplementation can effectively increase iron stores in iron-deficient runners within 6 wk and, if Hbmass is compromised, may enhance endurance capacity by facilitating erythropoiesis. Hbmass appears a more sensitive tool for measuring changes in whole body hemoglobin than hemoglobin concentration and may be useful in the diagnosis and follow-up for iron deficiency.

Effect of 10 week beta-alanine supplementation on competition and training performance in elite swimmers.

Although some laboratory-based studies show an ergogenic effect with beta-alanine supplementation, there is a lack of field-based research in training and competition settings. Elite/Sub-elite swimmers (n = 23 males and 18 females, age = 21.7 ± 2.8 years; mean ± SD) were supplemented with either beta-alanine (4 weeks loading phase of 4.8 g/day and 3.2 g/day thereafter) or placebo for 10 weeks. Competition performance times were log-transformed, then evaluated before (National Championships) and after (international or national selection meet) supplementation. Swimmers also completed three standardized training sets at baseline, 4 and 10 weeks of supplementation. Capillary blood was analyzed for pH, bicarbonate and lactate concentration in both competition and training. There was an unclear effect (0.4%; ± 0.8%, mean, ± 90% confidence limits) of beta-alanine on competition performance compared to placebo with no meaningful changes in blood chemistry. While there was a transient improvement on training performance after 4 weeks with beta-alanine (-1.3%; ± 1.0%), there was an unclear effect at ten weeks (-0.2%; ± 1.5%) and no meaningful changes in blood chemistry. Beta-alanine supplementation appears to have minimal effect on swimming performance in non-laboratory controlled real-world training and competition settings.

Within-subject variation in hemoglobin mass in elite athletes.

UNLABELLED: Illicit autologous blood transfusion to improve performance in elite sport is currently undetectable, but the stability of longitudinal profiles of an athlete's hemoglobin mass (Hbmass) might be used to detect such practices. PURPOSE: Our aim was to quantify within-subject variation of Hbmass in elite athletes, and the effects of potentially confounding factors such as reduced training or altitude exposure. METHODS: A total of 130 athletes (43 females and 87 males) were measured for Hbmass an average of six times during a period of approximately 1 yr using carbon monoxide rebreathing. Linear mixed models were used to quantify within-subject variation of Hbmass and its associated analytical and biological components for males and females, as well as the effects of reduced training and moderate altitude exposure in certain athletes. RESULTS: The maximum within-subject coefficient of variation (CV) for Hbmass was 3.4% for males and 4.0% for females. The analytical CV was ~2.0% for both males and females, and the long-term biological CV, after allowing for analytical variation, was 2.8% for males and 3.5% for females. On average, self-reported reduced training resulted in a 2.8% decrease in Hbmass and altitude exposure increased Hbmass by 1.5% to 2.9%, depending on the duration and type of exposure. CONCLUSIONS: The within-subject CV for Hbmass of ~4% indicates that athletes may experience changes up to ~20% with a 1-in-1000 probability. Changes of this magnitude for measures taken a few months apart suggest that Hbmass has a limited capacity to detect autologous blood doping. However, changes in Hbmass may be a useful indicator when combined with other measures of blood manipulation.