An appropriate dietary regime meeting athletes’ individual requirements is a prerequisite of their health, optimal function and physical fitness. Together with genetic advantages and efficient training, a well-designed diet frequently determines their performance and ultimately decides about their success or failure in sport (IOC, 2010; Kreider et al., 2010). A daily food energy intake that is insufficient or exceeds energy expenditure may adversely affect the athlete’s body mass, composition and function, and impair performance.
When more energy is consumed than expanded causing the energy balance to be positive, the surplus energy turns into fat tissue that increases body mass which may impair the athlete’s motor skills and performance. However, excessive energy intake does not mean that the demand for nutritional substances is met. When a diet is rich in energy yet poor in certain minerals, vitamins or protein, qualitative undernourishment may develop.
On the other hand, a negative energy balance caused by less energy being taken in than is expended over a period of time can lead to energetic undernourishment that is frequently accompanied by macro and micronutrient deficiency, particularly when such periods are prolonged. Energetic undernourishment may hinder the growth of the athlete’s body, disturb its function and cause weight loss and general debilitation, thus increasing the athlete’s ability to exercise and increasing the risk of injuries (Arieli and Constantini, 2012; Burke, 2001; Loucks, 2004). It is relevant to note that the natural regulatory mechanism based on appetite and satiety is not a reliable indicator of a person’s nutritional status and of whether or not their nutritional requirements are met (Carlsohn et al., 2011; Loucks, 2004). This implies a need to monitor the athletes’ energy balance to ensure that they are adequately nourished.
To make a dietary plan effective, the athlete’s energy expenditure must be estimated to determine how much energy they actually need. While the number of international studies on the energy expenditure of athletes in different sports and events is increasing (Clemente-Suárez, 2015; Coelho et al., 2010; Milia, 2014; Praz et al., 2014) few research reports on the training energy expenditure and daily energy expenditure of Polish elite athletes are available. To make up for the lack of necessary data, the generally available energy requirement norms are used as a basis for planning athletes’ dietary intakes. The Academy of Nutrition and Dietetics, Dietitians of Canada (2016) and the American College of Sports Medicine (ACSM) (2016) recommend using norms developed for people who are physically very active, i.e. whose physical activity level (PAL) is 1.8-2.3; according to the WHO, the norms for PAL of 2.0-2.4 are appropriate (Carlsohn et al., 2011; FAO/WHO/UNU, 2005). Another option includes nutritional guidelines, recommendations and standards specifically addressing athletes’ needs, many of which take into account the demands of their sport discipline (Celejowa, 2012). However, as all these values, norms and recommendations are relatively broad, calculating precisely the diet’s energy value becomes problematic. For instance, a difference between dietary reference intake for an athlete aged 23 years with body mass of 70 kg may exceed 2000 kcal a day. One reason for undertaking this study was therefore a need to estimate the actual energy expenditure of Polish elite athletes representing various speed-strength sports and to compare these values with energy requirement norms recommended for athletes.
There are several methods for measuring energy expenditure, such as direct calorimetry, indirect calorimetry, the doubly labelled water (DLW) method, heart rate monitoring, a kinematic method and a chronometric-tabular method utilizing physical activity questionnaires, diaries and tables (Ainslie et al., 2003; Lipert and Jegier, 2009; Strath et al., 2013). The methods differ in convenience as well as in the reliability and accuracy of measurements. It is thought that the most reliable of them are indirect calorimetry, DLW and indirect calorimetry (Ainslie, 2003). Even so, inherent weaknesses and high costs of the methods prevent them from being widely used in studies on athletes’ training energy expenditure or daily energy expenditure. For instance, the direct calorimetry method is not feasible outside a laboratory setting, the indirect calorimetry method requires the subject to wear a mask connected with a respiratory gas analyser, and the DLW is unsuitable for measurements that have to be made during short training units. Therefore, this study was also undertaken to estimate and compare energy expenditure values yielded by a kinematic method and a chronometric-tabular method which are considered to be the most convenient for athletes.
The study was carried out on 30 Polish athletes (15 women and 15 men aged 20 to 34 years) representing aerobic-endurance sports (7 women and 7 men) and speed-strength sports (8 women and 8 men). Based on athletes’ sex and sport, four study groups were formed: WAE (n = 7) – female aerobic-endurance athletes (speed skating, cross-country-skiing, steeplechase, mountain biking); WSS (n = 8) – female speed-strength athletes (volleyball, downhill skiing, middle-distance running, sport climbing, lawn tennis, kayaking); MAE (n = 7) – male aerobic-endurance athletes (rowing, walking, cross-country skiing, biathlon, mountain biking); and MSS (men, speed-strength, n = 8) – male speed-strength athletes (kayaking, middle-distance running, fencing, speed skating, handball, volleyball, ice hockey).
The inclusion criterion for the study was athletes representing the national performance level in their respective disciplines. All participants were elite athletes, e.g. multiple champions of Poland and members of the national team. Some of them were among the top performers in international competitions. All measurements were performed during the preparatory period of the annual training cycle.
Design and Procedures
The baseline measurements of the participants’ anthropometric variables included: body height (BH), body mass (BM), body fat mass (%BF), fat-free mass (FFM), and muscle mass (MM). The body composition variables were determined with a body composition analyser BodyComp MF+ made by Akern, Italy. Participants’ body mass was measured using a Tanita TBF-300 digital scale.
The measurements of participants’ daily energy expenditure were made over a period of 7 days under natural conditions. A chronometric-tabular method and a kinematic method were used for this purpose.
Participants were instructed to record all daily activities and their duration on the energy expenditure forms over a seven-day period. Then, using the available energy-cost tables for activities typical of daily living, work and sport, the energy expenditure of each activity was established. The numbers thus obtained were added up to estimate the DEE of individual participants (Celejowa, 2012).
The second method involved the use of triaxial accelerometers (ActiTrainer by ActiGraph, USA) that participants wore on the belts in the hip area (as required by the device’s manual) for the seven days of the study. To make sure that readings were reliable, data concerning participants’ sex, age, body height and body mass were entered into the devices before they were used for the first time.
The statistical significance of differences between values obtained for male and female athletes was tested using the t-Student test, and whenever the data failed to meet its assumptions, the Mann-Whitney U-test was applied (a non-parametric equivalent of the t-Student test). ANOVA was performed on more than two groups of means to find significant differences between them. In the next step, significant differences were subjected to a more detailed analysis using the Tukey’s test. If ANOVA assumptions were not met, a Kruskal-Wallis test and multiple-comparison post-hoc tests being a non-parametric equivalent of ANOVA were used.
All test values and coefficients were assumed to be statistically significant at p < 0.05.
Anthropometric characteristics of the studied athletes and differences between the groups’ means
|DIFFERENCES BETWEEN MEAN VALUES|
|WE - WP||-2.3||-0.1||-1.6||-0.6||1.9||-2.5|
|ME – MP||2.3||-0.2||-7.1||-2.0||1.3||-7.6|
|M – W||-1.2||9.5||11.5||1.3||-8.6*||15.5|
Overall and relative (adjusted for athletes’ body mass) values of DEE by group and measurement method
|DEE||DEE/kg BM||DEE||DEE/kg BM|
|DIFFERENCES BETWEEN MEAN VALUES|
|DEE||DEE/kg BM||DEE||DEE/kg BM|
|M – W||759.7||2.6||687.3||3.7|
|WAE – WSS||-213.1||-2.2||-115.4||-0.8|
|MAE - MSS||-258.7||1.2||12.9||3.3|
|MAE – WE||735.4||4.4||752.4||6.0|
|MSS – WSS||781.0||1.0||624.1||1.9|
|MAE – WSS||522.3||2.2||637.0||5.2|
|MSS - WAE||994.1||3.2||739.5||2.7|
DEE values yielded by the kinematic method were significantly lower than those obtained with the chronometric-tabular method. The difference amounted to around 25%, i.e. 903.9 kcal/24h or 13 kcal/24 per kg of body mass. The kinematic method’s tendency to produce lower values of energy expenditure (by around 20-30%) was observed in all between-group comparisons.
In all cases, the overall values of DEE were significantly higher in men. Depending on the measurement method the difference was 687 kcal/24h (accelerometers) or 759 kcal/24h (questionnaires). The relative values of DEE (adjusted for body mass) were also higher in men, but the difference between mean DEEs obtained with the questionnaire method was not statistically significant. The mean DEE of aerobic-endurance athletes and speed-strength athletes of the same sex was not significantly different, but significant differences were found between the mean DEE of male and female athletes.
Significant differences were also found between the minimum and maximum DEE of athletes in particular groups, which were unrelated to their sex and sport. Depending on the measurement method, the difference between the lowest and the highest DEE of female and male athletes was 612-1111 kcal and 1025-1976 kcal, respectively.
In the next stage of analysis, athletes’ DEE was estimated taking into account body composition to obtain energy expenditure per 1 kilogram of fat-free body mass (DEE/kg FFM) and 1 kg of muscle mass (DEE/kg MM) (Table 3).
DEE values adjusted for athletes’ body composition by group and measurement method
|DEE/kg FFM||DEE/kg MM||DEE/kg FFM||DEE/kg MM|
|DIFFERENCES BETWEEN MEAN VALUES|
|DEE/kg FFM||DEE/kg MM||DEE/kg FFM||DEE/kg MM|
|M – W||-3.2||-6.6||-0.2||-1.0|
|WAE – WSS||-1.2||0.4||0.8||3.1|
|MAE – MSS||2.8||6.6||4.7||9.9|
|MAE – WAE||-1.1||-3.2||2.1||3.1|
|MP – WSS||-5.0||-9.5||-1.8||-3.7|
|MAE – WSS||-2.3||-2.8||3.0||6.2|
|MSS – WAE||-3.9||-9.9||-2.6||-6.8|
Neither athletes’ sex nor sport caused significant differences between their mean relative DEE. However, while in the previous comparisons all DEE values (overall and per kilogram of body mass) were higher for men, their counterparts adjusted for FFM and MM were higher for women. This regularity was observed in all comparisons of the questionnaire data and in most comparisons of results yielded by the kinematic method.
The mean values of athletes’ DEE were subsequently compared with energy requirement norms developed for the Polish population, taking PAL of 1.75-2.4 (Table 4) (Jarosz, 2012), and with norms created specifically for athletes (taking into account participants’ respective sports) (Celejowa, 2012). As can be seen, mean DEE derived for all athletes from the questionnaire data matched energy requirement norms for PAL 2.2 and mean DEE calculated from accelerator readings corresponded to norms for PAL 1.75.
Discrepancies between energy requirement norms and athletes’ DEE obtained with 2 measurement methods (means for all athletes)
|Athletes’ DEE according to 2 measure ment methods||Energy requirement norms1|
|very active persons (from PAL 1.75 to PAL 2.4)||Athletes|
|PAL||PAL||PAL||PAL||Period I2||Period II3|
|Measurement method||Differences between norms and DEE (kcal/24h)|
In most cases (14 athletes), DEE values obtained for individual participants with the kinematic method were below energy requirement norms for PAL 1.75; for 12 athletes (7 women and 5 men) the norms for PAL 1.75 were appropriate, and for 4 athletes the norms for PAL 2.0 were appropriate (Table 5). As far as the questionnaire method is concerned, the individual DEE of most athletes matched the norms for PAL 2.2, in the case of 8 and 6 athletes the norms for PAL 2.0 and PAL 2.4 were the most appropriate, and the DEE of 3 athletes corresponded to norms for PAL 1.75. Only one athlete’s mean DEE matched the norms for athletes.
Number and percentage of athletes in the sample whose DEE obtained with the two measurement methods was the most compatible with particular energy requirement norms
|Norms Measure method||< PAL 1.75||PAL 1.75||PAL 2.0||PAL 2.2||PAL 2.4||SPORT I|
The weekly differences between athletes’ minimum and maximum DEE on training and non-training days were also compared (Table 6). In some athletes, the difference between the highest and lowest values of DEE exceeded 2500 kcal on training days (TD max–min) and 3000 kcal when the maximum DEE on a training day and the minimum DEE on a non-training day (TD– NTD) were compared. Therefore, particular athletes’ DEE can vary significantly over a week.
Mean differences between minimum and maximum values of DEE on training days (TD max-min) and training and non-training days (TD-NTD) by measurement method
|TD||TD - NTD||TD||TD - NTD|
|max - min||max - min|
In this study, energy expenditure of the study participants was evaluated using a kinematic method utilising accelerometer readings and a chronometric-tabular method requiring athletes to self-complete daily physical activity questionnaires. Both methods are considered to be the most convenient in studies with athletes. DEE values obtained with the first method proved to be lower by 20-30% (an equivalent of around 900 kcal/24h) compared with those yielded by the questionnaire method. A similar difference was reported by Rafamantanantso et al. (2002), Koehler et al. (2011), and Brage et al. (2015), in whose studies daily energy expenditure derived from accelerometers readings was lower by around 20%.
The dietary studies indicate that the daily energy requirements of athletes may range between 2500-2600 kcal/24h and 7000-8000 kcal/24h (Celejowa, 2012; Kreider et al., 2010; Schetty, 2005), but ultra-endurance athletes competing in events such as ultramarathons, multi-stage races, etc. may require more than 10000 kcal/24h (Barrero et al., 2014; Bescos et al., 2012).
The highest individual DEE obtained in this study was 5107 kcal (the chronometric-tabular method) and 3659 kcal (accelerometers). An interesting finding was that in both methods the lowest individual DEE was below 2500 kcal, the smallest one (1719 kcal) having been determined for a female athlete from accelerometer readings. These findings are in line with previous studies as athletes practising different sports, particularly women, had DEE below 2500 kcal (Eisenmann and Wickel, 2007; Frączek et al., 2018; Ismail et al., 1997).
One of the main factors determining athlete’s energy expenditure is their sex. In female athletes, a higher percentage of fat tissue and lower oxygen uptake at rest and during exercise slow down their basal and post-exercise metabolism, thus reducing their daily energy expenditure. The results of this study also confirm that women have lower DEE values. All DEE values (both total and relative, i.e. adjusted for athletes’ body mass) proved to be higher in men, although relative DEEs obtained for female and male athletes in aerobic-endurance and speed-strength sports did not significantly differentiate men from women.
DEE values were also calculated with respect to athletes’ body composition to evaluate their energy expenditure per kilogram of fat-free body mass (DEE/kg FFM) and muscle mass (DEE/kg MM). The analysis of relative DEEs did not show male and female athletes to be significantly different from each other.
Another factor that determines athletes’ energy expenditure includes demands of particular sports disciplines; however, in this study the mean DEE of male and female athletes was not found to be significantly different considering this factor alone.
An interesting observation that was made while analysing athletes’ DEE was its different values between athletes of the same sex and of the same sports discipline and different DEEs in the same athletes depending on the day of the week. Depending on the measurement method, differences between the lowest and the highest values of DEE amounted to 612- 1111 kcal/24h (for female athletes) and to 1025-1976 kcal/24h (for male athletes). Differences between the relative DEE in the same groups ranged between 20 and 40%.
Similar differences between the DEE of athletes representing similar sport disciplines were found in a study of Japanese athletes (Motonaga et al., 2006), whose energy expenditure was estimated at an average of 4514 ± 739 kcal. The lowest and the highest DEE of two athletes calculated as four-day averages were 3993 ± 1052 kcal and 5960 ± 1496 kcal, respectively (a difference of 1967 kcal). Interestingly, the athlete with the smallest DEE ran longer training distances (ca. 758 km/month) than the other athlete (680 km/month). The athletes were comparable regarding their anthropometric characteristics.
In this study, participants’ DEE changed between the days of the week depending on training intensity on a given day or a lack of training. The overall DEE of 10 players of the Canadian Interuniversity women’s volleyball team studied by Woodruff and Meloche (2013) was estimated at an average of 3479 ± 603 kcal and their relative DEE at 46 ± 6 kcal/kg of body mass. The mean DEE of some players was different by more than 1000 kcal. In all cases the difference between the lowest and highest DEE exceeded 1000 kcal; in 4 athletes it was 1500 kcal and in 2 as much as 2000 kcal. In this study, the mean weekly DEE of 2 players of the first-league women’s volleyball team was 2537 ± 530 kcal and 2280 ± 454 kcal (accelerometer readings) and 3634 ± 684 kcal and 3125 ± 541 kcal (questionnaires), respectively. The largest differences between their DEE noted on particular days of the study were 1931 and 1703 kcal. It was also interesting to find that athletes had significantly different DEE between training days; in some athletes the difference exceeded 2500 kcal.
It is not unusual for sport dieticians to use dietary norms created for the general population as a reference in calculating food energy intake for athletes. The Academy of Nutrition and Dietetics, Dietitians of Canada (2016) and the American College of Sports Medicine (2016) recommend using dietary norms for people who are physically very active, i.e. whose physical activity is best described by a PAL of 1.8-2.3. According to the WHO, dietary norms for PAL of 2.0-2.4 are appropriate (Carlsohn et al., 2011; FAO/WHO/UNU, 2005). Dietary guidelines, recommendations and norms for athletes proposed in the Polish and international literature, many of which were developed with the demands of particular sports in mind, can also be used for reference (Celejowa, 2012; Kreider et al., 2010; Potgieter et al., 2013). The International Society of Sports Nutrition (ISSN) recommends a daily energy intake of 50-80 kcal/kg of body mass, an equivalent of 2500-8000 kcal/24h for an athlete weighing between 50 and 100 kg (Kreider et al., 2010). This guideline is challenged by the results of this and other studies, according to which the daily energy requirement of athletes in various sports can be lower than the lowest values recommended by the ISSN, i.e. 2500 kcal/24h and/or less than 50 kcal/kg/24h. In this study, participants’ mean DEEs were compared with the Polish energy requirement norms established for the general population (PAL of 1.75-2.4) (Jarosz, 2012) and with the norms recommended for athletes in different sports (Celejowa, 2012). According to the accelerometer readings, the DEE of 14 athletes was below the norms for PAL of 1.75, in 12 athletes it matched the norms for PAL of 1.75, and in the case of 4 athletes the norms for PAL 2.0 were appropriate. In all cases the dietary recommendations developed for athletes were rejected as inappropriate.
The authors of other studies also found athletes’ actual DEE to be different from the established energy requirement norms. Having studied the energy expenditure of 29 young male adults aged 18-27 years, Rush et al. (2008) reported that their PAL varied from 1.7 to as much as 3.2 (2.2 on average). The PAL of basketball players examined by Silve et al. (2013) ranged from 2.2 to 3.7 (2.8 ± 0.4 on average). Ebine et al. (2002) reported that the PAL of professional soccer players in their study was in the range of 1.81 to 2.81 (2.19 ± 0.3 on average). Ismail et al. (1997) estimated the energy expenditure of 84 male athletes and 24 female athletes representing 9 and 4 sport disciplines, respectively, as corresponding to a PAL of 1.72-2.58 (men) and 1.65-2.34 (women). In the study by Carlson et al. (2011), the actual PAL of 40 young athletes (60%) aged 15 years was lower than 2.0 (1.9 on average), i.e. below that established by the WHO for adult athletes.
From the above it follows that using the energy requirement norms developed for athletes and/or individuals who are physically very active to develop dietary plans for athletes may disturb their energy balance. This may happen when the actual energy expenditure of an athlete is substantially at variance with the broadly defined dietary recommendations. The planning of dietary strategies for athletes must therefore be based on monitoring their energy expenditure to ensure that the proposed energy intake matches their real requirements for energy.
- The kinematic method produced lower values of athletes’ daily energy expenditure (DEE) compared with the questionnaire method, which imply the necessity to monitor them for actual energy expenditure.
- Significantly different DEE of the same athlete depending on the day of the week is an argument for monitoring the energy balance of particular athletes.
- The DEE of male and female athletes was not found to be influenced by their sport; this implies that the type of sport is not a strong determinant of energy expenditure.
- Athletes’ sex significantly differentiated between the mean energy expenditure of male and female athletes, which was higher in the former. However, the differences between the athletes’ relative energy expenditure (adjusted for body mass and body composition) were either small or non-significant.
- The actual energy requirement of an athlete can be significantly different from the energy intake norms recommended in the literature. Using the norms as the only reference for developing dietary plans for athletes may result in the miscalculation of calorie intake and energy balance disturbances.
This paper was supported by the University of Physical Education in Krakow, Grant no 35/MIN/INB/2013, NN/602-190/13
Academy of Nutrition and Dietetics. Position of the Academy of Nutrition and Dietetics Dietitians of Canada and the American College of Sports Medicine: Nutrition and Athletic Performance. Can J Diet Pract Res 2016; 77(1): 54
ACMS Nutrition and Athletic Performance. Special communications: Joint Position Statement. Med Sci Sports Exerc 2016; 48(3): 543–568
Ainslie PN Reilly T Westerterp KR. Estimating human energy expenditure. A review of techniques with particular reference to doubly labelled water. Sports Med 2003; 33(9): 683-698
Bescós R Rodríguez FA Iglesias X Benítez A Marina M Padullés JM Torrado P Vázquez J Knechtle B. High energy deficit in an ultraendurance athlete in a 24-hour ultracycling race. Proc Bayl Univ Med Cent 2012; 25(2): 124-128
Brage S Westgate K Franks PW Stegle O Wright A Ekelund U Wareham NJ. Estimation of Free-Living Energy Expenditure by Heart Rate and Movement Sensing: A Doubly-Labelled Water Study. PLoS One 2015; 8; 10(9): 1-19
Carlsohn A Scharhag-Rosenberger F Cassel M Weber J de Guzman Guzman A Mayer F. Physical activity levels to estimate the energy requirement of adolescent athletes. Pediatr Exerc Sci 2011; 23(2): 261-269
Celejowa I. Żywienie w sporcie [Nutrition in Sport] Wyd. Lek. PZWL Warszawa; 2012
Clemente-Suárez VJ. Psychophysiological response and energy balance during a 14-h ultraendurance mountain running event. Appl Physiol Nutr Metab 2015; 40(3): 269-273
Coelho DB Coelho LG Mortimer LA Condessa LA Ferreira-Junior JB Borba DA Oliveira BM Bouzas-Marins JC Soares DD SilamiGarcia E. Energy expenditure estimation during official soccer matches. BRJB 2010; 4(4): 246-255
Eisenmann JC Wickel EE. Estimated energy expenditure and physical activity patterns of adolescent distance runners. Int J Sport Nutr Exerc Metab 2007; 17(2): 178-188
Ebine N Rafamantanantsoa HH Nayuki Y Yamanaka K Tashima K Ono T Saitoh S Jones PJ. Measurement of total energy expenditure by the doubly labelled water method in professional soccer players. J Sports Sci 2002; 20(5): 391-397
- Export Citation
Ebine N, Rafamantanantsoa HH, Nayuki Y, Yamanaka K, Tashima K, Ono T, Saitoh S, Jones PJ. Measurement of total energy expenditure by the doubly labelled water method in professional soccer players.)| false J Sports Sci, 2002; 20(5): 391-397 12043828 10.1080/026404102317366645
FAO/WHO/UNU Expert Consultation. Human energy requirements. Scientific back-ground papers from the Joint FAO/WHO/UNU Expert Consultation. October 17-24 2001. Rome Italy. Food and Nutrition Technical Report Series 35ff; 2005
Frączek B Grzelak A Klimek AT. Energy expenditure of endurance and strength athletes in the light of the Polish energy intake standards. Int J Occup Med Environ Health 2019; 32(1): 1-13
IOC consensus statement on sports nutrition. J Sports Sci 2011; 29(Supl.1): 3-4
Ismail MN Wannudri W Zawiah H. Energy expenditure studies to predict requirements of selected national athletes. Malays J Nutr 1997; 3(1): 71-81
Jarosz M. Normy żywienia dla populacji polskiej – nowelizacja [Human Nutrition Recommendations for Polish Population - an Update]. Instytut Żywności i Żywienia 2012
Koehler K Braun H De Marées M Fusch G Fusch C Schaenzer W. Assessing Energy Expenditure in Male Endurance Athletes: Validity of the SenseWear Armband. Med Sci Sports Exerc 2011; 43(7): 1328
Kreider RB Wilborn CD Taylor L Campbell B Almada AL Collins R Cooke M Earnest CP Greenwood M Kalman DS Kerksick CM Kleiner SM Leutholtz B Lopez H Lowery LM Mendel R Smith A Spano M Wildman R Willoughby DS Ziegenfuss TN Antonio J. ISSN exercise & sport nutrition review: research & recommendations. J Int Soc Sports Nutr 2010; 2(7): 7
Lipert A Jegier A. The measurement of physical activity. Med Sport 2009; 25: 3(6): 155-168
Milia R Roberto S Pinna M Palazzolo G Sanna I Omeri M Piredda S Migliaccio G Concu A Crisafulli A. Physiological responses and energy expenditure during competitive fencing. Appl Physiol Nutr Metab 2014; 39(3): 324-328
Motonaga K Yoshida S Yamagami F Kawano T Takeda E. Estimation of total daily energy expenditure and its components by monitoring the heart rate of Japanese endurance athletes. J Nutr Sci Vitaminol 2006; 52(5): 360-367
Potgieter S. Sport nutrition: A review of the latest guidelines for exercise and sport nutrition from the American College of Sport Nutrition the International Olympic Committee and the International Society for Sports Nutrition. S Afr J Clin Nutr 2013; 26(1): 6-16
- Export Citation
Potgieter S. Sport nutrition: A review of the latest guidelines for exercise and sport nutrition from the American College of Sport Nutrition, the International Olympic Committee and the International Society for Sports Nutrition.)| false S Afr J Clin Nutr, 2013; 26(1): 6-16 10.1080/16070658.2013.11734434
Praz C Léger B Kayser B. Energy expenditure of extreme competitive mountaineering skiing. Eur J Appl Physiol 2014; 114(10): 2201-2211
Rafamantanantsoa HH Ebine N Yoshioka M Higuchi H Yoshitake Y Tanaka H Saitoh S Jones PJ. Validation of three alternative methods to measure total energy expenditure against the doubly labeled water method for older Japanese men. J Nutr Sci Vitaminol 2002; 48(6): 517-523
- Export Citation
Rafamantanantsoa HH, Ebine N, Yoshioka M, Higuchi H, Yoshitake Y, Tanaka H, Saitoh S, Jones PJ. Validation of three alternative methods to measure total energy expenditure against the doubly labeled water method for older Japanese men.)| false J Nutr Sci Vitaminol, 2002; 48(6): 517-523 12778890 10.3177/jnsv.48.517
Rush EC Valencia ME Plank LD. Validation of a 7-day physical activity diary against doubly-labelled water. Ann Hum Biol 2008; 35(4): 416–421
Silva AM. Santos DA Matias CN Minderico CS Schoeller DA Sardinha LB. Total energy expenditure assessment in elite junior basketball players: a validation study using doubly labeled water. J Strength Cond Res 2013; 27(7): 1920-1927
- Export Citation
Silva AM. Santos DA, Matias CN, Minderico CS, Schoeller DA, Sardinha LB. Total energy expenditure assessment in elite junior basketball players: a validation study using doubly labeled water.)| false J Strength Cond Res, 2013; 27(7): 1920-1927 22990574 10.1519/JSC.0b013e31827361eb
Strath SJ Kaminsky LA Ainsworth BE Ekelund U Freedson PS Gary RA Richardson CR Smith DT Swartz AM. Guide to the assessment of physical activity: Clinical and research applications: a scientific statement from the American Heart Association. Circulation 2013; 12; 128(20): 2259-2279
- Export Citation
Strath SJ, Kaminsky LA, Ainsworth BE, Ekelund U, Freedson PS, Gary RA, Richardson CR, Smith DT, Swartz AM. Guide to the assessment of physical activity: Clinical and research applications: a scientific statement from the American Heart Association.)| false Circulation, 2013; 12; 128(20): 2259-2279 24126387 10.1161/01.cir.0000435708.67487.da
Woodruff SJ Meloche RD. Energy availability of female varsity volleyball players. Int J Sport Nutr Exerc Metab 2013; 23(1): 24-30