Energy Expenditure of Elite Male and Female Professional Tennis Players During Habitual Training.

Understanding the daily energy expenditure of athletes during training is important to support recovery, adaptation, and the maintenance of performance. The aim of the current research was to assess the total daily energy expenditure (TDEE) and the acute energy expenditure (EE) of tennis training sessions during habitual training of elite tennis players. Using a cohort study design, 27 (n = 10, male; age; 22.3 ± 3.2 years and n = 17, female; age: 23.8 ± 3.5 years) elite singles tennis players were assessed for TDEE and tennis training EE. Using Actiheart activity monitors during a 2- to 5-day training period, male players were analyzed for 26 days and 33 (1.3 ± 0.5 sessions/day) tennis training sessions, and female players for 43 days and 58 (1.2 ± 0.4 sessions/day) tennis training sessions. Male TDEE (4,708 ± 583 kcal/day) was significantly higher than female (3,639 ± 305 kcal/day). Male absolute and relative tennis training EEs (10.2 ± 2.3 kcal/min and 7.9 ± 1.4 kcal·hr-1·kg-1) were significantly higher than those of females (7.6 ± 1.0 kcal/min and 6.8 ± 0.9 kcal·hr-1·kg-1). The resting metabolic rate was assessed via indirect calorimetry. The physical activity level for both groups was 2.3 AU. The TDEE of male and female players during habitual training now highlights the continual cycle of high energy demands experienced by the elite tennis player. The broad ranges of TDEE and EE reported here suggest individual assessment and nutritional planning be prioritized, with a particular focus on carbohydrate requirements.

Under-Fuelling for the Work Required? Assessment of Dietary Practices and Physical Loading of Adolescent Female Soccer Players during an Intensive International Training and Game Schedule.

Previous studies demonstrate that "under-fuelling" (i.e., reduced carbohydrate (CHO) and energy intake (EI) in relation to recommended guidelines) is prevalent within adult female soccer players, the consequence of which may have acute performance and chronic health implications. However, the dietary practices of adolescent female soccer players, a population who may be particularly at risk for the negative aspects of low energy availability (LEA), are not well documented. Accordingly, we aimed to quantify EI and CHO intake, physical loading and estimated energy availability (EA) in elite national team adolescent female soccer players (n = twenty-three; age, 17.9 ± 0.5 years) during a 10-day training and game schedule comprising two match days on day six (MDa) and nine (MDb). The players self-reported their EI via the remote food photography method, whilst the physical loading and associated exercise energy expenditure were assessed via GPS technology. The relative CHO intake was significantly greater (all p < 0.05) on the day before the first match (MD-1a) (4.1 ± 0.8 g·kg-1), on the day before the second match (MD-1b) (4.3 ± 1.1 g·kg-1), MDa (4.8 ± 1.2 g·kg-1) and MDb (4.8 ± 1.4 g·kg-1) in comparison to most other days (<4 g·kg-1). The mean daily measured EA over the 10-day period was 34 ± 12 kcal·kg FFM-1·day-1 (with six players, i.e., 34%, presenting LEA), though, when adjusting the energy intake for potential under-reporting, these values changed substantially (44 ± 14 kcal·kg FFM-1·day-1, only one player was classed as presenting LEA). Such data suggest that the prevalence of LEA amongst female team sport athletes may be over-estimated. Nonetheless, players are still likely under-fuelling for the work required in relation to the daily CHO recommendations (i.e., >6 g·kg-1) for intensive training and game schedules. These data provide further evidence for the requirement to create and deliver targeted player and stakeholder education and behaviour change interventions (especially for younger athletes) that aim to promote increased daily CHO intake in female soccer players.

An Observational Case Series Measuring the Energy Expenditure of Elite Tennis Players During Competition and Training by Using Doubly Labeled Water.

PURPOSE: An understanding of an athlete's total daily energy expenditure (TEE) is necessary to inform nutritional strategies, particularly where daily training and competitive demands are highly variable. This observational case series assessed the TEE of elite tennis players during high-level competition. METHODS: Senior female singles participants (FS: n = 3; 21 [1] y; ranked  Women's Tennis Association [WTA] top 125-375), an FS junior (n = 1; 16 y; ranked WTA top 350), and a men's doubles player (n = 1; 26 y; ranked Association of Tennis Professionals [ATP] top 5) were assessed for TEE (using the doubly labeled water method) during a 9- to 14-day period, which included training, Wimbledon Championships, WTA/ATP International Tournaments, Junior/Senior International Tennis Federation, and Wimbledon Junior Championships. One female (FS3) did not exercise from day 4 following injury. RESULTS: TEE for men's doubles was 4586 kcal·d-1 (67 kcal·kg-1 fat-free mass [FFM]; daily activity 98 [74] min). Noninjured adult female participants' TEEs were 3396 and 3948 kcal·d-1 (66 and 81 kcal·kg-1 FFM; daily activity durations were 139 [84] min and 150 [66] min, respectively), while TEE for the injured athlete was 2583 kcal·d-1 (45.7 kcal·kg-1; daily nonexercise activity duration was <45 min). The junior player TEE was 3988 kcal·d-1 (78.2 kcal·kg-1 FFM; daily activity of 131 [66] min). CONCLUSION: This observational case series positions tennis as a highly energetically demanding sport with variability evident between individuals (ie, TEE between 60 and 90 kcal·kg-1 FFM). Accordingly, nutritional strategies that promote sufficient energy availability should be emphasized with individual variability suitably assessed prior to prescription.

Variability in energy expenditure is much greater in males than females.

In mammals, trait variation is often reported to be greater among males than females. However, to date, mainly only morphological traits have been studied. Energy expenditure represents the metabolic costs of multiple physical, physiological, and behavioral traits. Energy expenditure could exhibit particularly high greater male variation through a cumulative effect if those traits mostly exhibit greater male variation, or a lack of greater male variation if many of them do not. Sex differences in energy expenditure variation have been little explored. We analyzed a large database on energy expenditure in adult humans (1494 males and 3108 females) to investigate whether humans have evolved sex differences in the degree of interindividual variation in energy expenditure. We found that, even when statistically comparing males and females of the same age, height, and body composition, there is much more variation in total, activity, and basal energy expenditure among males. However, with aging, variation in total energy expenditure decreases, and because this happens more rapidly in males, the magnitude of greater male variation, though still large, is attenuated in older age groups. Considerably greater male variation in both total and activity energy expenditure could be explained by greater male variation in levels of daily activity. The considerably greater male variation in basal energy expenditure is remarkable and may be explained, at least in part, by greater male variation in the size of energy-demanding organs. If energy expenditure is a trait that is of indirect interest to females when choosing a sexual partner, this would suggest that energy expenditure is under sexual selection. However, we present a novel energetics model demonstrating that it is also possible that females have been under stabilizing selection pressure for an intermediate basal energy expenditure to maximize energy available for reproduction.

Total energy expenditure is repeatable in adults but not associated with short-term changes in body composition.

Low total energy expenditure (TEE, MJ/d) has been a hypothesized risk factor for weight gain, but repeatability of TEE, a critical variable in longitudinal studies of energy balance, is understudied. We examine repeated doubly labeled water (DLW) measurements of TEE in 348 adults and 47 children from the IAEA DLW Database (mean ± SD time interval: 1.9 ± 2.9 y) to assess repeatability of TEE, and to examine if TEE adjusted for age, sex, fat-free mass, and fat mass is associated with changes in weight or body composition. Here, we report that repeatability of TEE is high for adults, but not children. Bivariate Bayesian mixed models show no among or within-individual correlation between body composition (fat mass or percentage) and unadjusted TEE in adults. For adults aged 20-60 y (N = 267; time interval: 7.4 ± 12.2 weeks), increases in adjusted TEE are associated with weight gain but not with changes in body composition; results are similar for subjects with intervals >4 weeks (N = 53; 29.1 ± 12.8 weeks). This suggests low TEE is not a risk factor for, and high TEE is not protective against, weight or body fat gain over the time intervals tested.

Energy Expenditure of Female International Standard Soccer Players: A Doubly Labeled Water Investigation.

PURPOSE: The purpose of this study is to quantify total daily energy expenditure (TEE) of international adult female soccer players. METHODS: Twenty-four professional players were studied during a 12-d period where they participated in an international training camp (also inclusive of two competitive games) representing the English national team. The TEE was assessed via the doubly labeled water method during the full 12 d as well as the initial 4-d period before game one. Energy intake was also assessed (via weighed food analysis) during the initial 4-d period to permit estimation of energy availability (EA). RESULTS: Mean TEE did not differ (P = 0.31) between the 12-d (2693 ± 432 kcal·d-1; range, 2105-3507 kcal·d-1; 54 ± 6 kcal·kg-1 fat-free mass [FFM]) versus the 4-d assessment period (2753 ± 359 kcal·d-1; range, 1942-3280 kcal·d-1; 56 ± 8 kcal·kg-1 FFM). Mean 4-d energy intake was 1923 ± 357 kcal·d-1 (range, 1639-2172 kcal·d-1) and mean activity energy expenditure was 1069 ± 278 kcal·d-1 (range, 155-1549 kcal·d-1). When assessed for estimated EA, 88% of players were categorized with low EA status according to the threshold of <30 kcal·kg-1 FFM. Mean daily carbohydrate intake equated to 3.3 ± 0.7 g·kg-1 body mass. CONCLUSIONS: When compared with previously published data from adult male players, we demonstrate that the relative daily energetic requirements of engaging in professional soccer training and match play are comparable between sexes. From a practical perspective, data suggest that practitioners should likely focus education and behavior change strategies on "fuelling" for match play and training to optimize both player health and performance.

Daily energy expenditure through the human life course.

Total daily energy expenditure ("total expenditure") reflects daily energy needs and is a critical variable in human health and physiology, but its trajectory over the life course is poorly studied. We analyzed a large, diverse database of total expenditure measured by the doubly labeled water method for males and females aged 8 days to 95 years. Total expenditure increased with fat-free mass in a power-law manner, with four distinct life stages. Fat-free mass-adjusted expenditure accelerates rapidly in neonates to ~50% above adult values at ~1 year; declines slowly to adult levels by ~20 years; remains stable in adulthood (20 to 60 years), even during pregnancy; then declines in older adults. These changes shed light on human development and aging and should help shape nutrition and health strategies across the life span.

Energy Expenditure of a Male and Female Tennis Player during Association of Tennis Professionals/Women's Tennis Association and Grand Slam Events Measured by Doubly Labeled Water.

METHODS: Doubly labeled water assessed TEE during a 17-d period analyzed by days 1 to 7 (P1) and 7-17 (P2) which included a Women's Tennis Association/Association of Tennis Professionals tournament and culminated at the Wimbledon Championships. Daily training and match loads were assessed using a 10-point Borg scale multiplied by time. Match data were provided by video analysis and player tracking technology. RESULTS: The TEE during P1 for the female player was 3383 kcal·d-1 (63.5 kcal·kg-1) fat-free mass (FFM) with 362 points played over 241 min in three matches covering a distance of 2569 m, with an additional 875 min training. During P2, TEE was 3824 kcal·d-1 (71.7 kcal·kg-1) FFM with 706 points played over 519 min during five matches, covering a distance of 7357 m with an additional 795 min training. The TEE during P1 for the male player was 3712 kcal·d-1 (56.3 kcal·kg-1) FFM with 133 points played over 88 min during one match covering 1125 m, with an additional 795 min training. During P2, TEE was 5520 kcal·d-1 (83.7 kcal·kg-1) FFM with 891 points played over 734 min during five matches, covering 10,043 m, with an additional 350 min training. CONCLUSIONS: This novel data positions elite tennis, played at the highest level, as a highly energetic demanding sport, highlighting that nutritional strategies should ensure sufficient energy availability during competition schedules.

An Assessment of the Validity of the Remote Food Photography Method (Termed Snap-N-Send) in Experienced and Inexperienced Sport Nutritionists.

The remote food photography method, often referred to as "Snap-N-Send" by sport nutritionists, has been reported as a valid method to assess energy intake in athletic populations. However, preliminary studies were not conducted in true free-living conditions, and dietary assessment was performed by one researcher only. The authors, therefore, assessed the validity of Snap-N-Send to assess the energy and macronutrient composition in experienced (EXP, n = 23) and inexperienced (INEXP, n = 25) sport nutritionists. The participants analyzed 2 days of dietary photographs, comprising eight meals. Day 1 consisted of "simple" meals based around easily distinguishable foods (i.e., chicken breast and rice), and Day 2 consisted of "complex" meals, containing "hidden" ingredients (i.e., chicken curry). The estimates of dietary intake were analyzed for validity using one-sample t tests and typical error of estimates (TEE). The INEXP and EXP nutritionists underestimated energy intake for the simple day (mean difference [MD] = -1.5 MJ, TEE = 10.1%; -1.2 MJ, TEE = 9.3%, respectively) and the complex day (MD = -1.2 MJ, TEE = 17.8%; MD = -0.6 MJ, 14.3%, respectively). Carbohydrate intake was underestimated by INEXP (MD = -65.5 g/day, TEE = 10.8% and MD = -28.7 g/day, TEE = 24.4%) and EXP (MD = -53.4 g/day, TEE = 10.1% and -19.9 g/day, TEE = 17.5%) for both the simple and complex days, respectively. Interpractitioner reliability was generally "poor" for energy and macronutrients. The data demonstrate that the remote food photography method/Snap-N-Send underestimates energy intake in simple and complex meals, and these errors are evident in the EXP and INEXP sport nutritionists.

Case Study: Muscle Atrophy, Hypertrophy, and Energy Expenditure of a Premier League Soccer Player During Rehabilitation From Anterior Cruciate Ligament Injury.

Maintaining muscle mass and function during rehabilitation from anterior cruciate ligament injury is complicated by the challenge of accurately prescribing daily energy intakes aligned to energy expenditure. Accordingly, we present a 38-week case study characterizing whole body and regional rates of muscle atrophy and hypertrophy (as inferred by assessments of fat-free mass from dual-energy X-ray absorptiometry) in a professional male soccer player from the English Premier League. In addition, in Week 6, we also quantified energy intake (via the remote food photographic method) and energy expenditure using the doubly labeled water method. Mean daily energy intake (CHO: 1.9-3.2, protein: 1.7-3.3, and fat: 1.4-2.7 g/kg) and energy expenditure were 2,765 ± 474 and 3,178 kcal/day, respectively. In accordance with an apparent energy deficit, total body mass decreased by 1.9 kg during Weeks 1-6 where fat-free mass loss in the injured and noninjured limb was 0.9 and 0.6 kg, respectively, yet, trunk fat-free mass increased by 0.7 kg. In Weeks 7-28, the athlete was advised to increase daily CHO intake (4-6 g/kg) to facilitate an increased daily energy intake. Throughout this period, total body mass increased by 3.6 kg (attributable to a 2.9 and 0.7 kg increase in fat free and fat mass, respectively). Our data suggest it may be advantageous to avoid excessive reductions in energy intake during the initial 6-8 weeks post anterior cruciate ligament surgery so as to limit muscle atrophy.

Assessment of Energy Expenditure of a Professional Goalkeeper From the English Premier League Using the Doubly Labeled Water Method.

Purpose: To better understand the energy and carbohydrate (CHO) requirements of a professional goalkeeper (GK) in elite soccer, the authors quantified physical loading, energy expenditure (EE), and energy intake (EI) during a 2-games-per-week in-season microcycle. Methods: Daily training and match loads were assessed in a professional GK (age 26 y, height 191 cm, body mass 85.6 kg) from the English Premier League using global positioning systems (GPS) and ProZone®, respectively. Assessments of EE (using the doubly labeled water method) and EI (using food diaries supported by the remote food photographic method and 24-h recalls) were also completed. Results: Physical loading was greater on match days than training days as inferred from total distance (4574 [432] vs 1959 [500] m), average speed (48 [5] vs 40 [4] m/min), and distance completed when jogging (993 [194] vs 645 [81] m) and running (138 [16] vs 21 [20] m). Average daily energy and macronutrient intake appear reflective of a self-selected "low-CHO" diet (energy 3160 [381] kcal, CHO 2.6 [0.6], protein 2.4 [0.4], fat 1.9 [0.3] g/kg body mass). Mean daily EE was 2894 kcal. Conclusions: The average daily EE of this professional GK was approximately 600 kcal/d lower than that previously reported in outfield players from the same team. Such data suggest that the nutritional requirements of a GK should be carefully considered depending on the required daily and weekly loading patterns.

Energy expenditure in professional flat jockeys using doubly labelled water during the racing season: Implications for body weight management.

To formulate individualized dietary strategies for jockeys, it is vital that energy requirements are quantified. We measured total energy expenditure (TEE) over two separate weeks in spring and summer using doubly labelled water in a group of male flat jockeys (n = 8, 36.9 ± 5.7 years, 164 ± 8 cm, 54.6 ± 2.5 kg). Total energy intake (TEI) was self-recorded, as were all riding and structured exercise activity. Mean daily TEE was 10.83 (±2.3) and 10.66 (±1.76) MJ, (p = .61) respectively. Self-reported TEI were 6.03 (±1.7) and 5.37 (±1.1) MJ (p = .40), respectively, and were significantly lower than TEE (p = .01). Mean race rides were 17 (±6) and 13 (±3; p = 0.37) and horses ridden at morning exercise were 8 (±6) and 7 (±4; p = .77) respectively. Additional structured exercise was 76.25 (±95.1) and 52.5 (±80.9) min per week (p = .35), respectively. At the individual level, TEE was related to body mass and the level of non-racing physical activity, but not riding. Physical activity levels for TEE were 1.76 (±0.37) and 1.69 (±0.27; p = .59) and appear modest when compared with other athletes, and similar to age-matched non-athletes, suggesting that conventional sport-specific nutritional recommendations do not appear applicable. The large discrepancy between TEE and TEI suggests significant under reporting of dietary intake. These data now provide an appropriate framework from which to formulate jockey nutritional guidelines to promote the ability to achieve the daily weight target and improve athlete welfare.

Energy Intake and Expenditure of Professional Soccer Players of the English Premier League: Evidence of Carbohydrate Periodization.

In an attempt to better identify and inform the energy requirements of elite soccer players, we quantified the energy expenditure (EE) of players from the English Premier League (n = 6) via the doubly labeled water method (DLW) over a 7-day in-season period. Energy intake (EI) was also assessed using food diaries, supported by the remote food photographic method and 24 hr recalls. The 7-day period consisted of 5 training days (TD) and 2 match days (MD). Although mean daily EI (3186 ± 367 kcals) was not different from (p > .05) daily EE (3566 ± 585 kcals), EI was greater (p < .05) on MD (3789 ± 532 kcal; 61.1 ± 11.4 kcal.kg-1 LBM) compared with TD (2956 ± 374 kcal; 45.2 ± 9.3 kcal.kg-1 LBM, respectively). Differences in EI were reflective of greater (p < .05) daily CHO intake on MD (6.4 ± 2.2 g.kg-1) compared with TD (4.2 ± 1.4 g.kg-1). Exogenous CHO intake was also different (p < .01) during training sessions (3.1 ± 4.4 g.h-1) versus matches (32.3 ± 21.9 g.h-1). In contrast, daily protein (205 ± 30 g.kg-1, p = .29) and fat intake (101 ± 20 g, p = .16) did not display any evidence of daily periodization as opposed to g.kg-1, Although players readily achieve current guidelines for daily protein and fat intake, data suggest that CHO intake on the day before and in recovery from match play was not in accordance with guidelines to promote muscle glycogen storage.

Energy intake and expenditure assessed 'in-season' in an elite European rugby union squad.

Rugby union (RU) is a complex high-intensity intermittent collision sport with emphasis placed on players possessing high lean body mass and low body fat. After an 8 to 12-week pre-season focused on physiological adaptations, emphasis shifts towards competitive performance. However, there are no objective data on the physiological demands or energy intake (EI) and energy expenditure (EE) for elite players during this period. Accordingly, in-season training load using global positioning system and session rating of perceived exertion (sRPE), alongside six-day assessments of EE and EI were measured in 44 elite RU players. Mean weekly distance covered was 7827 ± 954 m and 9572 ± 1233 m with a total mean weekly sRPE of 1776 ± 355 and 1523 ± 434 AU for forwards and backs, respectively. Mean weekly EI was 16.6 ± 1.5 and 14.2 ± 1.2 megajoules (MJ) and EE was 15.9 ± 0.5 and 14 ± 0.5 MJ. Mean carbohydrate (CHO) intake was 3.5 ± 0.8 and 3.4 ± 0.7 g.kg(-1) body mass, protein intake was 2.7 ± 0.3 and 2.7 ± 0.5 g.kg(-1) body mass, and fat intake was 1.4 ± 0.2 and 1.4 ± 0.3 g.kg(-1) body mass. All players who completed the food diary self-selected a 'low' CHO 'high' protein diet during the early part of the week, with CHO intake increasing in the days leading up to a match, resulting in the mean EI matching EE. Based on EE and training load data, the EI and composition seems appropriate, although further research is required to evaluate if this diet is optimal for match day performance.

Body composition assessment of English Premier League soccer players: a comparative DXA analysis of first team, U21 and U18 squads.

Professional soccer players from the first team (1st team, n = 27), under twenty-one (U21, n = 21) and under eighteen (U18, n = 35) squads of an English Premier League soccer team were assessed for whole body and regional estimates of body composition using dual-energy X-ray absorptiometry (DXA). Per cent body fat was lower in 1st team (10.0 ± 1.6) compared with both U21 (11.6 ± 2.5, P = 0.02) and U18 (11.4 ± 2.6, P = 0.01) players. However, this difference was not due to variations (P = 0.23) in fat mass between squads (7.8 ± 1.6 v. 8.8 ± 2.1 v. 8.2 ± 2.4 kg, respectively) but rather the presence of more lean mass in 1st team (66.9 ± 7.1 kg, P < 0.01) and U21 (64.6 ± 6.5 kg, P = 0.02) compared with U18 (60.6 ± 6.3 kg) players. Accordingly, fat mass index was not different (P = 0.138) between squads, whereas lean mass index was greater (P < 0.01) in 1st team players (20.0 ± 1.1 kg · m(-2)) compared with U18 players (18.8 ± 1.4 kg · m(-2)). Differences in lean mass were also reflective of higher lean tissue mass in all regions, for example, upper limbs/lower limbs and trunk. Data suggest that training and nutritional interventions for younger players should therefore be targeted to lean mass growth as opposed to body fat loss.

Assessment of energy expenditure in elite jockeys during simulated race riding and a working day: implications for making weight.

Professional jockeys are unique amongst weight-making athletes in that they are required to make weight on a daily basis by often using potentially hazardous methods, such as food deprivation, dehydration, and forced vomiting. To allow the prescription of accurate energy intake (EI), it is essential to understand the energy requirements of jockeys; however, these data are currently not known. Therefore, we measured the energy expenditure (EE) of professional jockeys during a simulated race ride and for a working day (nonracing) that involved typical stable duties. The accuracy of 2 portable lightweight devices, the Polar RS400 commercial heart rate monitor (CHRM) and the Actiheart monitor (AH) were initially assessed during 30 min of exercise compared with respiratory gas analysis (GA) (n = 9). No significant difference was observed (p > 0.05) and 95% limits of agreement analysis (LoA) showed that CHRM was more closely related to GA (bias: -0.015; LoA: -0.049, +0.019 MJ) than AH (bias: -0.007; LoA: -0.073, +0.059 MJ). A laboratory-based 2-mile (3.2-km) racing protocol was created and EE was assessed using CHRM, GA, and AH. We report that a typical race expends 0.18 (SD ±0.03) MJ. Finally, in a separate group of jockeys (n = 8), 24-h EE was assessed using CHRM. The mean (±SD) EE for a typical day was 11.26 (±1.49) MJ. Additionally, we measured EI using 7-day self-reporting food record diaries. Mean EI was 7.24 (±0.92) MJ, largely consumed as 2 main meals. These data provide a platform to implement dietary strategies that create appropriate weight-loss targets and therefore improve the physical and mental well-being of professional jockeys.