Total Energy Expenditure, Energy Intake, and Body Composition in Endurance Athletes Across the Training Season: A Systematic Review

Comparison of Energy Expenditure Observed between Scheduled Activities in Collegiate Team-Sport Female Athletes

Energy needs of female team-sport athletes are poorly understood with no evidence highlighting differences present between scheduled activities. The purpose of this study was to examine the difference in energy expenditure between NCAA Division II female basketball (BBALL) and lacrosse (LAX) athletes during different scheduled team activities. Female BBALL (n = 13; 19.8 ± 1.3 yrs; 173.9 ± 13.6 cm; 74.6 ± 9.1kg; 27.1 ± 3.2%fat) and LAX (n = 20; 20.4 ± 1.8yrs; 168.4 ± 6.6cm; 68.8 ± 8.9kg; 27.9 ± 3.1%fat) athletes were outfitted with heart rate and activity monitors during four consecutive days on five different occasions (20 days total) across an entire academic year to assess differences in total daily activity energy expenditure (TDEE), activity energy expenditure (AEE), and physical activity level (PAL). Data were categorized by type of scheduled daily activities: Practice, Game, Conditioning, or Off. Independent of day type, TDEE, AEE, and PAL levels were greater (p < 0.05) in BBALL athletes. For each sport, TDEE, AEE, and PAL were significantly different (p < 0.05) between classified activity days. BBALL and LAX athletes experienced higher values on game days for TDEE, AEE, and PAL, with the lowest values experienced on off days. In conclusion, calculated levels of TDEE, AEE, and PAL in female collegiate BBALL and LAX athletes were determined to be different, irrespective of the scheduled activity.

Impact of training volume and experience on amateur Ironman triathlon performance

PURPOSE

To investigate the association between training volume, sleep time, signs and symptoms of excessive training (overtraining), and  previous triathlon experience with overall and split race times in the Ironman distance triathlon.

METHODS

Ninety-nine triathletes (19 women and 80 men) answered an online survey containing questions about anthropometric characteristics (body mass and height), weekly training volume (hours per day and days per week), previous experience in Ironman distance triathlon race, and signs and symptoms of excessive training. Data of race times of all participants were collected by a single race (the Ironman Brazil 2019 - Florianópolis). All surveys were collected between 28 and 30 days before the race. The athlete was instructed to answer the questions according to what was happening in the week before completing the survey.

RESULTS

Total race time did not differ among those who trained up to 14 h per week (11:28:46±01:54:30 h:min:sec), between 15 and 20 h per week (11:37:31±01:20:26 h:min:sec) or more than 20 h per week (11:30:18±01:31:28 h:min:sec) (p = 0.922). Total race time of the triathletes who presented (12:42:22±01:49:36 h:min:sec) or no (11:23:06±01:29:02 h:min:sec) unintentional body mass loss (p = 0.006), feeling (12:46:17±02:03:13 h:min:sec) or no (11:24:09±01:28:07 h:min:sec) of decreased performance (p = 0.009) or feeling (12:08:58±01:47:12 h:min:sec) or no (11:16:34±01:24:53 h:min:sec) loss of energy (p = 0.011) in the week prior to the race were significantly different. Triathletes who had a previous experience in Ironman races achieved a better performance (11:15:21±01:32:04 h:min:sec) than those without previous experience (12:06:38±01:32:10 h:min:sec) (p = 0.010).

CONCLUSION

In summary, high volumes of training (more than 20 h per week), when performed forty days before a race, may not have a positive impact on performance compared to lower volumes of training (up to 14 h per week). However, athletes who had a previous experience in Ironman race presented better results in swimming splits and overall race time. Moreover, the presence of overtraining symptoms, such as unintentional loss of weight, sensation of fatigue and/or performance decrease impact negatively triathlon performance.

Weight cycling practices in sport: A risk factor for later obesity?

Weight cycling, repeated cycles of weight loss and weight regain over time, is commonplace amongst many population groups. Although the effect of weight cycling on future obesity and cardiometabolic risk is still hotly debated, evidence does indicate that individuals who were normal weight prior to weight cycling are more susceptible to its adverse consequences than those who were overweight or with obesity. Athletes, and particularly those who compete in the so-called weight-sensitive sports, are prone to dieting and weight cycling practice owing to the competitive advantage to be gained from manipulating their body weight. However, in comparison with the general population, athletes tend to be leaner and weight loss phases more rapid and superimposed on a background of a high level of physical activity. In this context, it can be questioned whether weight cycling in this subpopulation will indeed increase risk for future obesity. It is perhaps surprising that despite recognition that athletes commonly partake in weight cycling during their career, studies are scarce and firm conclusions regarding the effect of this practice on future cardiometabolic risk remain to be drawn. In this review, we examine weight cycling prevalence and strategies in athletes and the current evidence relating to its short- and long-term consequences. In addition, a conceptual framework relating the dynamics of weight loss and recovery to athlete characteristics will be discussed, highlighting the need for well-controlled, prospective studies in this specific subpopulation.

[Musculoskeletal laboratory diagnostics in competitive sport]

Hintergrund

Die labordiagnostische Untersuchung stellt eine wichtige Möglichkeit zur Beurteilung und Optimierung der Leistungs- und Regenerationsfähigkeit professioneller Athleten dar. Ferner ist sie für die Prävention, Diagnostik und Rehabilitation von Verletzungen und Überbelastungen von Bedeutung.

Fragestellung

Ziel dieser Arbeit ist die Darstellung muskuloskelettaler laborchemischer Parameter, die relevante Erkenntnisse für die medizinische Betreuung von Leistungssportlern liefern.

Material und Methoden

Literaturrecherche und narratives Review.

Ergebnisse

Die Bestimmung des Vitamin-D-, Calcium- und Knochenstoffwechsels stellt die laborchemische Basisdiagnostik im Rahmen der Beurteilung des Skelettstatus mit zusätzlichem präventivem Nutzen bezüglich muskuloskelettaler Verletzungen dar. Ferner können muskuläre Serummarker, z. B. Laktatdehydrogenase (LDH), Kreatinkinase (CK), Myoglobin und Aspartat-Aminotransferase (ASAT), helfen, eine metabolische Adaptation an das physische Training festzustellen und Aussagen über die muskuläre Arbeitslast und mögliche Schädigungen zu gewinnen. Die Energieverfügbarkeit kann durch eine entsprechende Bilanzierung sowie die laborchemische Bestimmung der Makro- und Mikronährstoffe eingeschätzt und optimiert werden.

Schlussfolgerungen

Die labordiagnostische Untersuchung besitzt in der Betreuung von Athleten eine sportartenübergreifende klinische Relevanz. Sie dient der Erreichung einer höchstmöglichen Leistungsfähigkeit sowie optimalen Prävention von Knochen- und Muskelverletzungen, wobei sämtliche Mangelzustände (z. B. Vitamin D) ausgeglichen werden sollten. Durch eine Periodisierung der laborchemischen Untersuchungen, mit zumindest zwei Labordiagnostiken im Jahr, und Aufstellung individueller Variabilitäts- und Referenzbereiche kann ferner eine bessere Beurteilbarkeit erreicht werden.

Energy Intake Deficiency Promotes Bone Resorption and Energy Metabolism Suppression in Japanese Male Endurance Runners: A Pilot Study

It has been reported that male athletes face increased risk for low energy availability and resulting health consequences similar to female athletes. The present study aimed to reveal the energy status of Japanese male runners and to examine the association between energy deficiency and physiological characteristics such as energy metabolism, bone health, and hormonal status. Six male collegiate long-distance runners during a training season participated in this study. Energy intake (EI) was assessed using 3-day dietary records with food pictures. Exercise energy expenditure (EEE) was determined by the HR-VO₂ method. Body composition and bone status were measured by dual-energy X-ray absorptiometry. Energy availability (EA) was calculated by subtraction of EEE from EI and normalized by fat-free mass (FFM). Energy balance (EB) was calculated EI minus estimated total energy expenditure (TEE). Resting energy expenditure (REE) was measured by indirect calorimetry using the Douglas bag technique, and blood sampling was conducted to assess hormonal status. The mean EA of the subjects was 18.9 ± 6.8 kcal/kg FFM/day, and severe negative EB (range: -1444 ~ -722 kcal/d) was observed. REE of four runners was suppressed, and moreover, bone resorption was promoted in all subjects. The data in our study suggested that energy deficiency could promote bone resorption and energy metabolism suppression in Japanese male endurance runners. Additional short- and long-term studies are needed to clarify the health risks caused by energy deficiency in male athletes and explore strategies to prevent health problems related to energy deficiency in long-distance runners.

Performance and Health Decrements Associated With Relative Energy Deficiency in Sport for Division I Women Athletes During a Collegiate Cross-Country Season: A Case Series

The purpose of this case series was to evaluate the presence of low Energy Availability (EA) and its impact on components of Relative Energy Deficiency in Sport (RED-S) in a population of female collegiate runners. Seven female NCAA Division I athletes (age: 22.3 ± 1.5 yrs; height: 169.7 ± 5.7 cm; weight: 58.3 ± 4.1 kg) were tracked from August until February, covering the beginning (Pre XC), end (Post XC) of their competitive cross country season, and beginning of the following track season (Pre Track). The athletes were assessed for female athlete triad (Triad) risk, energy availability, body composition, resting metabolic rate (RMR), nutritional intake, and blood markers (including vitamin D, ferritin, and triiodothyronine (T3)). From Pre XC to Post XC there were no significant differences in body mass, fat free mass or body fat percentage. At Pre XC, mean EA was 31.6 ± 13.3 kcal/kg FFM∙d^-1. From Post XC to Pre Track, there was a significant increase in body mass (59.1 ± 5.1 to 60.6 ± 5.7 kg, p<0.001,d=0.27). From Post XC to Pre Track, there was a significant increase in RMR (1466 ± 123.6 to 1614.6 ± 89.1 kcal·d^-1, p<0.001,d=2.6). For 25(OH) vitamin D, there was a significant reduction from Pre XC to Post XC (44.1 ± 10.6 vs 39.5 ± 12.2 ng·mL^-1, p=0.047,d=-0.4), and a significant increase from Post XC to Pre Track (39.5 ± 12.2 vs. 48.1 ± 10.4 ng·mL^-1, p=0.014,d=0.75). For ferritin, there was a trend towards a decrease from Pre XC to Post XC (24.2 ± 13.2 vs. 15.7 ± 8.8 ng·mL^-1, p=0.07, d=-0.75), as well as a trend toward an increase from Post XC to Pre Track (15.7 ± 8.8 vs. 34.1 ± 18.0 ng·mL^-1, p=0.08, d=1.3). No differences in T3 were observed across time points. Average Triad risk score was 2.3 ± 1.4. Notably, 5 of 7 athletes met criteria for moderate risk. Despite many athletes meeting criteria for low EA and having elevated Triad risk assessment scores, most were able to maintain body mass and RMR. One athlete suffered severe performance decline and a reduced RMR. Surprisingly, she was the only athlete above the recommended value for ferritin. Following increased nutritional intake and reduced training volume, her performance and RMR recovered. Changes in body mass and body composition were not indicative of the presence of other concerns associated with RED-S. This exploratory work serves as a guide for future, larger studies for tracking athletes, using RMR and nutritional biomarkers to assess RED-S.

A systematic comparison of commonly used stoichiometric equations to estimate fat oxidation during exercise in athletes

BACKGROUND

Over the last half-century, different stoichiometric equations for calculating the energy cost of exercise based upon the combustion of mixtures of carbohydrates, fats, and proteins have been proposed and modified. With the means of indirect calorimetry, while measuring oxygen uptake, carbon dioxide production, and urinary urea nitrogen excretion, the contribution of specific substrates to overall energy production can be estimated. However, even with their long history of application, no previous studies have evaluated whether the use of different stoichiometric equations provides similar or distinct maximal fat oxidation rate (MFO) responses and information regarding MFO location (FAT<inf>max</inf>) in male athletes.

METHODS

Twenty healthy male athletes performed graded exercise testing (GXT) cycle ergometry using breath by breath gas analysis to assess fat oxidation and maximal oxygen uptake. Analysis of variance followed by within-equation effects, within-equation factors, and post hoc pairwise comparisons were used to examine within-equation differences.

RESULTS

Compared stoichiometric equations demonstrated significant differences in the mean and maximal fat oxidation rates, varying up to nearly 7%. FAT<inf>max</inf> differences, however, were not noticed.

CONCLUSIONS

Our findings suggest that for within-study designs, the equation used appears to be less important, but when inter-study comparisons are planned, caution is in order due to the presence of inter-equation differences.

Protein Requirements of Pre-Menopausal Female Athletes: Systematic Literature Review

This systematic literature review aimed to determine the protein requirements of pre-menopausal (e.g., 18-45 years) female athletes and identify if the menstrual cycle phase and/or hormonal contraceptive use influence protein requirements. Four databases were searched for original research containing pre-menopausal female athletes that ingested protein alongside exercise. The Academy of Nutrition and Dietetics Quality Criteria Checklist was used to determine study quality. Fourteen studies, which included 204 recreationally active or competitive females, met the eligibility criteria for inclusion in this review, and all were assessed as positive quality. The estimated average requirement (EAR) for protein intake of pre-menopausal recreational and/or competitive female athletes is similar for those undertaking aerobic endurance (1.28-1.63 g/kg/day), resistance (1.49 g/kg/day) and intermittent exercise (1.41 g/kg/day) of ~60-90 min duration. The optimal acute protein intake and influence of menstrual cycle phase or hormonal contraceptive use on protein requirements could not be determined. However, pre- and post-exercise protein intakes of 0.32-0.38 g/kg have demonstrated beneficial physiological responses in recreational and competitive female athletes completing resistance and intermittent exercise. The protein requirements outlined in this review can be used for planning and assessing protein intakes of recreational and competitive pre-menopausal female athletes.

Diet Quality, Carotenoid Status, and Body Composition in NCAA Division I Athletes

Objectives: In this paper, we examined diet quality and associations between changes in skin carotenoids and body composition among selected NCAA Division I athletes. Methods: Athletes from women's (rowing, swimming, gymnastics) and men's (swimming, wrestling) teams at a large Midwest university (N = 129) completed one online food frequency questionnaire and 2 in-person visits, once in-season and once out-of-season, to assess skin carotenoids and body composition. Diet quality was assessed via Healthy Eating Index-2015 (HEI). Carotenoids were measured via resonance Raman spectroscopy and body composition via dual-energy x-ray absorptiometry. ANOVA and Pearson correlations were used to test differences between teams and determine association between changes from in-season to out-of-season. Results: Mean HEI score for all athletes was 71.0. Women's rowing reported the highest diet quality (73.5), men's wrestling lowest (56.5). Skin carotenoids decreased for all teams, except men's wrestling, from in-season to out-of-season. Body fat percentage increased for women and decreased for men. There was a moderate inverse association between changes in skin carotenoids and body fat percentage (r = -.334, p = .001). Conclusions: Suboptimal diet quality coupled with decreases in skin carotenoids and increases in body fat percentage from in-season to out-of-season may justify dietitian-led interventions year-round to improve dietary patterns in collegiate athletes.

Effectiveness of Education Interventions Designed to Improve Nutrition Knowledge in Athletes: A Systematic Review

BACKGROUND

A range of nutrition education strategies are used to assist athletes to improve nutrition knowledge. Evaluation of nutrition education interventions guides the delivery of efficacious nutrition education for athletes.

AIM

Our aim was to systematically review sport/general nutrition education interventions delivered to athletes, and to evaluate their effectiveness.

METHODS

A search was conducted using terms related to nutrition knowledge, athletes, education, and intervention. Included studies had to be conducted in athletes (all calibres), use a scored nutrition knowledge assessment tool, and measure knowledge before and after a nutrition education intervention. Peer-reviewed and unpublished theses were included.

RESULTS

Thirty-two manuscripts (randomised controlled trial, n = 13; single-arm pre/post design, n = 19) met the inclusion criteria. Participants (n = 2180; mean age 17.4 ± 1.7 years) were mostly female (66.1%), university-level (56.3%) athletes based in the US (75%). Comparison of different education methods was limited since the majority of interventions (n = 28/36, 77.8%) used face-to-face education. Most intervention conditions (n = 19) had a total contact time of < 300 min (5 h). The majority of interventions (n = 30, 85.7%) reported significant knowledge improvement, with a mean increase of 16.1 ± 0.7% (mean effect size 1.72; range 0.4-17.1). Only 15.6% of studies used well-validated knowledge assessment tools (more than three types of validity or reliability testing).

CONCLUSIONS

Most interventions reported a significant improvement in nutrition knowledge. Unfortunately, the wide range of knowledge assessment tools with limited validation, and the predominant use of face-to-face interventions, prohibits identification of the most effective modality and dose for nutrition education in athletes.

Loss of iRhom2 accelerates fat gain and insulin resistance in diet-induced obesity despite reduced adipose tissue inflammation

BACKGROUND

Low-grade inflammation and metabolic dysregulation are common comorbidities of obesity, both of which are associated with alterations in iRhom2-regulated pro-inflammatory cytokine and epidermal growth factor receptor (EGFR) ligand signaling.

OBJECTIVE

Our objective was to determine the role of iRhom2 in the regulation of low-grade inflammation and metabolic dysregulation in a murine model of diet-induced obesity.

METHODS

Wild type (WT) and iRhom2-deficient mice were fed normal chow (NC) or a high-fat diet (HFD) starting at 5 weeks of age for up to 33 weeks. Body composition, glucose and insulin tolerance, feeding behavior, and indirect calorimetry were measured at defined time points. Adipose tissue cytokine expression and inflammatory lesions known as crown-like structures (CLS) were analyzed at the end-point of the study.

RESULTS

iRhom2-deficient mice show accelerated fat gain on a HFD, accompanied by insulin resistance. Indirect calorimetry did not demonstrate changes in energy expenditure or food intake, but locomotor activity was significantly reduced in HFD iRhom2-deficient mice. Interestingly, CLS, macrophage infiltration, and tumor necrosis factor (TNF) production were decreased in adipose tissue from HFD iRhom2-deficient mice, but circulating cytokines were unchanged. In inguinal and perigonadal fat, the EGFR ligand amphiregulin was markedly induced in HFD controls but completely prevented in iRhom2-deficient mice, suggesting a potentially dominant role of EGFR-dependent mechanisms over TNF in the modulation of insulin sensitivity.

CONCLUSIONS

This study elucidates a novel role for iRhom2 as an immuno-metabolic regulator that affects adipose tissue inflammation independent of insulin resistance.

Metabolite Shifts Induced by Marathon Race Competition Differ between Athletes Based on Level of Fitness and Performance: A Substudy of the Enzy-MagIC Study

This study compared metabolite shifts induced by training for, participation in, and recovery from a marathon race competition among athletes divided into three groups based on fitness (relative maximum oxygen uptake (VO₂max)) and performance levels (net running time). Plasma samples from 76 male runners participating in the Munich Marathon were analyzed for metabolite shifts using a targeted metabolomics panel. For the entire cohort of runners, pronounced increases were measured immediately after the race for plasma concentrations of acylcarnitines (AC), the ratio (palmitoylcarnitine + stearoylcarnitine)/free carnitine that is used as a proxy for the activity of the mitochondrial enzyme carnitine palmitoyltransferase, and arginine-related metabolites, with decreases in most amino acids (AA) and phospholipids. Plasma levels of AA and phospholipids were strongly increased 24 and 72 h post-race. Post-race plasma concentrations of AC and arginine-related metabolites were higher in the low compared to top performers, indicating an accumulation of fatty acids and a reliance on protein catabolism to provide energy after the marathon event. This study showed that marathon race competition is associated with an extensive and prolonged perturbation in plasma metabolite concentrations with a strong AC signature that is greater in the slower, less aerobically fit runners. Furthermore, changes in the arginine-related metabolites were observed.

Nutrition for Female Soccer Players-Recommendations

Soccer is one of the most popular sports in the world. As its number of players is increasing, the number of female players is also on the rise. However, there are limited data about how the diets of female soccer players should be designed. Thus, the aim of our work is to deliver concise nutritional recommendations for women practicing this sport. Based on a literature review, we emphasize that individual adjustment of the energy value of the diet is the key factor for the physical performance of female soccer players. Appropriate macronutrient intake makes it possible to achieve the proper energy value of the diet (5-10 g/kg body mass/day carbohydrates; 1.2-1.7 g/kg body mass/day proteins; <30% fats from energy). The micronutrients should be consumed in amounts corresponding to individual values recommended in national standards. Soccer players should pay special attention to the proper consumption of such micronutrients, as well as vitamins such as iron, calcium, and vitamin D. The right amount of fluid intake, consistent with the player's needs, is crucial in maximizing exercise performance. The diet of a female practicing soccer is usually characterized with low energy values, which increases the risk of various health consequences related to low energy availability. Monitoring the diets of female soccer players is, therefore, necessary.

Comparative Meta-Analysis of the Effect of Concentrated, Hydrolyzed, and Isolated Whey Protein Supplementation on Body Composition of Physical Activity Practitioners

Whey protein (WP) is a dairy food supplement and, due to its effects on fat-free mass (FFM) gain and fat mass (FM) loss, it has been widely consumed by resistance training practitioners. This review analyzed the impact of WP supplementation in its concentrated (WPC), hydrolyzed (WPH) and isolated (WPI) forms, comparing it exclusively to isocaloric placebos. Random effect meta-analyses were performed from the final and initial body composition values of 246 healthy athletes undergoing 64.5 ± 15.3 days of training in eight randomized clinical trials (RCT) collected systematically from five scientific databases. The weighted mean difference (WMD) was statistically significant for FM loss (WMD = −0.96, 95% CI = −1.37, −0.55, p < 0.001) and, in the analysis of subgroups, this effect was maintained for the WPC (WMD = −0.63, 95% CI = −1.19, −0.06, p = 0.030), with protein content between 51% and 80% (WMD = −1.53; 95% CI = −2.13, −0.93, p < 0.001), and only for regular physical activity practitioners (WMD = −0.95; 95% CI = −1.70, −0.19, p = 0.014). There was no significant effect on FFM in any of the scenarios investigated (p > 0.05). Due to several and important limitations, more detailed analyses are required regarding FFM gain.

Sex Difference in Triathlon Performance

This brief review investigates how sex influences triathlon performance. Performance time for both Olympic distance and Ironman distance triathlons, and physiological considerations are discussed for both elite and non-elite male and female triathletes. The relative participation of female athletes in triathlon has increased over the last three decades, and currently represents 25-40% of the total field. Overall, the sex difference in both Olympic and Ironman distance triathlon performance has narrowed across the years. Sex difference differed with exercise mode and exercise duration. For non-elite Ironman triathletes, the sex difference in swimming time (≈12%) is lower than that which was evidenced for cycling (≈15%) and running (≈18%). For elite triathletes, sex difference in running performance is greater for Olympic triathlon (≈14%) than it is for Ironman distance triathlon (≈7%). Elite Ironman female triathletes have reduced the gap to their male counterparts to less than 10% for the marathon. The sex difference in triathlon performance is likely to be due to physiological (e.g., VO2max) and morphological (e.g., % body fat) factors but hormonal, psychological and societal (e.g., lower participation rate) differences should also be considered. Future studies should address the limited evidence relating sex difference in physiological characteristics such as lactate threshold, exercise economy or peak fat oxidation.

Heterogeneity of endometriosis lesions requires individualisation of diagnosis and treatment and a different approach to research and evidence based medicine

Statistical significance is used to analyse research findings and is together with biased free trials the cornerstone of evidence based medicine. However traditional statistics are based on the assumption that the population investigated is homogeneous without smaller hidden subgroups. The clinical, inflammatory, immunological, biochemical, histochemical and genetic-epigenetic heterogeneity of similar looking endometriosis lesions is a challenge for research and for diagnosis and treatment of endometriosis. The conclusions obtained by statistical testing of the entire group are not necessarily valid for subgroups. The importance is illustrated by the fact that a treatment with a beneficial effect in 80% of women but with exactly the same but opposite effect, worsening the disease in 20%, remains statistically highly significant. Since traditional statistics are unable to detect hidden subgroups, new approaches are mandatory. For diagnosis and treatment it is suggested to visualise individual data and to pay specific attention to the extremes of an analysis. For research it is important to integrate clinical, biochemical and histochemical data with molecular biological pathways and genetic-epigenetic analysis of the lesions.

A Framework for Periodized Nutrition for Athletics

Over the last decade, in support of training periodization, there has been an emergence around the concept of nutritional periodization. Within athletics (track and field), the science and art of periodization is a cornerstone concept with recent commentaries emphasizing the underappreciated complexity associated with predictable performance on demand. Nevertheless, with varying levels of evidence, sport and event specific sequencing of various training units and sessions (long [macrocycle; months], medium [mesocycle; weeks], and short [microcycle; days and within-day duration]) is a routine approach to training periodization. Indeed, implementation of strategic temporal nutrition interventions (macro, meso, and micro) can support and enhance training prescription and adaptation, as well as acute event specific performance. However, a general framework on how, why, and when nutritional periodization could be implemented has not yet been established. It is beyond the scope of this review to highlight every potential nutritional periodization application. Instead, this review will focus on a generalized framework, with specific examples of macro-, meso-, and microperiodization for the macronutrients of carbohydrates, and, by extension, fat. More specifically, the authors establish the evidence and rationale for situations of acute high carbohydrate availability, as well as the evidence for more chronic manipulation of carbohydrates coupled with training. The topic of periodized nutrition has made considerable gains over the last decade but is ripe for further scientific progress and field application.

Effect of 12-Week Swimming Training on Body Composition in Young Women

Background: Systematic physical activity can permanently prevent disadvantageous developments in the human body. This is very important especially for women, for whom the maintenance of a lean body in good shape is sometimes a primary consideration. However, in most cases, this activity is taken randomly and does not produce the desired effects such as reducing body fat. The purpose of the study was to evaluate changes in female body composition induced by 12 weeks of swimming training compared to sedentary controls. Methods: Training sessions occurred three times per week (60 min/session). Height, body mass, and waist/hip circumference and waist/hips ratio (WHR) were measured. Body cell mass (BCM), total body water (TBW), extracellular (ECW) and intracellular water (ICW), fat mass (FM), lean mass (FFM), and muscle mass (MM) were measured using bioelectrical impedance (pre/post). Results: Training elicited decreases in hip circumference and increase in WHR. No changes were recorded in BCM, TBW, ECW, ICW, FM, FFM, and MM. Controls experienced decreases in values of BCM, ICW, and MM and increases in ECW. Conclusion: The applied swimming training did not significantly affect the body composition parameters. Inactivity also triggered a tendency toward unhealthy movement of water from the intracellular to extracellular space.

Long-Distance Triathletes' Intentions to Manipulate Energy and Macronutrient Intake Over a Training Macrocycle

This study explored the information sources long-distance triathletes used to inform their training and nutrition plans, and evaluated these plans over a training macrocycle. Seventy-four long-distance triathletes completed the online survey. Coaches were the most popular training information source (69%), whereas nonprofessional sources (internet 65%, other athletes 53%) were more popular than nutritionists (29%) for nutrition information. Attributes valued most in an information source were: source prior personal experience, individualized advice, breadth of knowledge, and credibility. Sixty-five percent of participants reported previously manipulating dietary intake to improve performance. Forty-three percent reported carbohydrate loading previously, but only 29% planned to carbohydrate load for their upcoming event. Thirty-six percent of participants planned to reduce carbohydrate intake at some point in training, predominantly early (28%) and toward the end (22%) of their macrocycles. Twenty percent of participants planned to maintain energy intake early, and increase (14%) or maintain energy intake (15%) mid-cycle. Triathletes' training plans showed intentions for concurrent increases in volume and intensity, rather than a classical periodized training progression. Limitations of this study include the lack of diet intake and training data, quantitative comparison with dietary guidelines and high/low carbohydrate classification, and an overrepresentation of women in the study cohort. This research showed the popularity of the internet and other athletes to inform triathletes' nutrition plans, and revealed intentions to reduce carbohydrate intakes alongside training load increases, contrary to professional guidelines. Understanding athletes' intentions and sources of nutrition information is crucial to developing effective nutrition education strategies.

Perspective: Towards Personalised Metabolic Coaching in Cancer

Although cancer survivorship has improved over the last decades, numbers of cancer incidence and prevalence are rising. Evidence is growing that lifestyle factors, such as physical activity, a healthy weight management and -diet, play an important role in first- and second line preventive strategies. When implementing a healthy lifestyle, the maintenance of the energy balance should be taken into account. The energy equilibrium is achieved when the energy intake (Ei) for one day is equal to the total daily energy expenditure (TEE). The latter is, among others, made up of the resting energy expenditure, its largest contributor (60-80% of TEE), and can be assessed by indirect calorimetry (i.e. the gold standard). The resting energy expenditure reflects the individual's minimal caloric need in 24h to support basal functions. In cancer patients, energy imbalances, expressed as a positive (Ei > TEE) or negative (Ei & TEE) energy balance, may occur and are characterised by weight gain or -loss respectively. As a corollary, shifts in fatmass and fatfree mass are reported. Adequate nutritional follow-up is necessary in order to meet the energy needs, since both positive and negative energy balances are known to have deteriorating effects on cancer prognosis and mortality. In the clinical setting, predictive formulas (e.g. Harris-Benedict equation) are often used to estimate the caloric need. However, both under- and overfeeding are reported when using equations. Therefore, we advise to use indirect calorimetry in the standard assessment of a patient's energy need in order to provide adequate metabolic coaching and -follow up.

ISSN exercise & sports nutrition review update: research & recommendations

Background

Sports nutrition is a constantly evolving field with hundreds of research papers published annually. In the year 2017 alone, 2082 articles were published under the key words ‘sport nutrition’. Consequently, staying current with the relevant literature is often difficult.

Methods

This paper is an ongoing update of the sports nutrition review article originally published as the lead paper to launch the Journal of the International Society of Sports Nutrition in 2004 and updated in 2010. It presents a well-referenced overview of the current state of the science related to optimization of training and performance enhancement through exercise training and nutrition. Notably, due to the accelerated pace and size at which the literature base in this research area grows, the topics discussed will focus on muscle hypertrophy and performance enhancement. As such, this paper provides an overview of: 1.) How ergogenic aids and dietary supplements are defined in terms of governmental regulation and oversight; 2.) How dietary supplements are legally regulated in the United States; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of nutritional approaches to augment skeletal muscle hypertrophy and the potential ergogenic value of various dietary and supplemental approaches.

Conclusions

This updated review is to provide ISSN members and individuals interested in sports nutrition with information that can be implemented in educational, research or practical settings and serve as a foundational basis for determining the efficacy and safety of many common sport nutrition products and their ingredients.

Anthropometric characteristics of top-class Olympic race walkers

BACKGROUND

Typical training programmes in elite race walkers involve high training volumes at low and moderate intensities, which have been reported to induce functional and structural adaptations at an anthropometric level. Since anthropometrical variables are closely related to movement efficiency and performance in endurance events, the aim of this study was to describe the anthropometric profile of world-class race walkers.

METHODS

Twenty-nine world-class race walkers (21 men and 8 women) participated in this study. Anthropometric characteristics, including height, body mass, eight skinfolds, five girths and four bone breadths were measured. Body composition, somatotype, somatotype dispersion mean, somatotype attitudinal mean and height to weight ratio, as well as skinfolds extremity to trunk ratio were also calculated.

RESULTS

Mean height, body mass and body mass index were 177.1±7.1 cm, 66.4±5.8 kg, and 21.2±1.3 kg·m2 for men and 165.6±4.5 cm, 53.6±3.7 kg, and 19.6±1.6 kg· m2 for women, respectively. Women presented greater body fat content (6.7±0.6 vs. 12.2±0.8%; very large effect), less muscle mass (65.6±4.6 vs. 61.6±2.6 kg; large effect), and were more endomorphic (large effect) than men. Men specialists in 20-km showed greater muscle mass (66.7±4.9 vs. 64.4±4.3 kg; moderate effect), and slightly higher skinfolds, girths, body fat content and were more mesomorphic than 50-km specialists (moderate effect).

CONCLUSIONS

The present study expands the limited knowledge on the anthropometric characteristics and somatotype elements of elite top-class race walkers. The characterisation of the morphology of elite race walkers provides coaches a reference values to control the training development of the race walker, as well as providing reference values to improve talent identification.

Evaluation of Dietary Intakes and Supplement Use in Paralympic Athletes

Dietary intakes and supplement use in Paralympic athletes remains largely unexplored, and specialized recommendations are lacking. The aim of this study was to evaluate nutrient intakes and supplement use in high-performance athletes with physical disabilities using three-day food records and a validated dietary supplement use questionnaire. A secondary aim examined gender differences in nutrient and supplement intakes. Male (n = 18) and female (n = 22) athletes were recruited from nine Paralympic sports through sporting organizations, coaches, and social media. Athletes generally met able-bodied recommendations for macronutrients. Male and female athletes often failed to meet the Recommended Dietary Allowance (RDA) or Adequate Intake (AI) for vitamin D, vitamin E, pantothenic acid, magnesium, and potassium. On average, females did not meet the RDA for iron and calcium, whereas males did not meet the RDA for vitamin A and folate. Commonly consumed supplements were vitamin D, protein powder, sport bars, and sport drinks. Analysis of diet and supplement use within this population shows several micronutrient deficiencies and irregular use of specific supplements. Athlete support and education is required to optimize nutrition in Paralympic athletes.

Validity of the ActiGraph GT3X+ and BodyMedia SenseWear Armband to estimate energy expenditure during physical activity and sport

OBJECTIVES

The purpose of this study was to assess the validity of the ActiGraph GT3X+ (GT3X+) and the BodyMedia SenseWear Armband (SWA) to estimate energy expenditure (EE) during physical activity and field sport movements.

DESIGN

Criterion validity.

METHODS

Twenty-six active adults completed a single 90min session involving alternating intervals of exercise (5min) and recovery (10min). Exercise involved walking (4km/h), jogging (8km/h), running (12km/h) or a sport-simulated circuit (three intervals). Participants wore two triaxial accelerometers (GT3X+ and SWA) and a portable gas analyser (MetaMax 3B), used as the criterion measure.

RESULTS

Total EE was significantly underestimated (p<0.01) by the GT3X+ (mean bias±SD: -374.5±132.84kJ; % difference=-29.3%) and SWA (-244.3±148.0kJ; -18.2%). Overestimations were made by both accelerometers during the walk (GT3X+: 27.4±30.8kJ; SWA: 32.1±15.4kJ) and jog (38.0±30.0kJ; 34.5±31.6kJ). Underestimations were evident during the run (-41.2±25.1kJ; -43.8±33.5kJ) and circuit (C1: GTX+: -127.2±41.6kJ; SWA: -86.1±40.2kJ). Error of estimation increased in magnitude as the intensity of exercise increased (GT3X+: 40.8-143.0kJ; SWA: 35.5-102.0kJ).

CONCLUSIONS

The ActiGraph GT3X+ and BodyMedia SWA do not provide valid EE estimates across a range of exercise modalities and intensities when compared to a criterion measure. Poor accuracy and large precision errors, particularly during high intensity and intermittent movement patterns, suggest these devices have limitations and should be used cautiously in the field.