Content uploaded by Nathalie Boisseau
Author content
All content in this area was uploaded by Nathalie Boisseau on Apr 03, 2015
Content may be subject to copyright.
62 — Boisseau, Vera-Perez, and Poortmans
Pediatric Exercise Science
, 2005, 17, 62-71
© 2005 Human Kinetics Publishers, Inc.
Food and Fluid Intake in Adolescent
Female Judo Athletes Before Competition
Nathalie Boisseau, Sonia Vera-Perez,
and Jacques Poortmans
Judo is a weight-class sport, meaning that there are weight-defined classes in
competitions. Regular body weight restrictions and/or nutritional imbalances
can alter growth and maturation states in adolescents. The aim of the present
study was to estimate to what extent female judo athletes (age 16.1 ± 0.3
years) modified food and drink intakes 3 weeks and 1 week before competi-
tion. Our findings indicate that unbalanced dietary intakes and “weight cut-
ting” might occur in female adolescent competitors. We conclude that dietary
recommendations are compulsory in order to educate coaches and young
judokas about adequate nutrition and safe weight control behaviors, as well as
the dangers of rapid weight loss and dehydration during adolescence.
Introduction
Adolescence involves anatomic, physiological, and metabolic changes (21).
The rapid growth and development that occurs has a profound effect on energy
and nutrient requirements (23). Thus, a balanced and sufficient dietary intake is
necessary during this period. Key nutrients needed by young people include pro-
tein to satisfy growth requirements and calcium to support bone accretion. It is
even more important to follow nutritional recommendations for child athletes (3).
Judo is a weight-class sport, as are wrestling and boxing. At the onset of
adolescence, a young athlete practicing Judo is classified in a specific weight cat-
egory. During the next 1 or 2 years, many individuals’ physical characteristics
increase significantly (height and body weight), although many attempt to remain
in the same weight class. Thus, most adolescent athletes in weight-class sports
compete in a class below their natural physiological body weight.
Scientific information on judo athletes remains scarce. To our knowledge,
there is no data on dietary habits and weight-loss strategies among adolescent judo
athletes. From a practical point of view, judo athletes typically follow a program
62
Boisseau and Vera-Perez are with the Laboratoire des Adaptations Physiologiques
aux Activités Physiques (LAPHAP), EA 3813, Faculté des Sciences du Sport de Poitiers, 4
allée Jean Monnet, F-86000 Poitiers, France. Poortmans is with Chimie physiologique,
Institut Supérieur d’Education Physique et de Kinésithérapie, Université Libre de Bruxelles,
B-1000, Bruxelles, Belgium.
Nutritional Aspects in Young Female Athletes — 63
of reduced eating a few days before the weigh-in of a competition and then gain
weight very rapidly afterward (“yo-yo” diet). Thus, 1 week before the official
weigh-in, judo athletes restrict food and drink. In addition, sweating by perform-
ing intensive exercises in a rubber or plastic suit is frequently used to stimulate
water-weight loss. Other strategies such as saunas and diuretics are frequently
used in the attempt to “make weight.” In extreme cases, fasting, cathartics, and/or
vomiting can also be employed. This rapid weight loss (“weight cutting”) induces
a high physical stress level that could affect growth and maturation processes (8,13).
At present it is unknown whether frequent and rapid weight-loss-and-gain cycles
in young judo athletes alter protein metabolism in adolescents.
In order to shed light on these peculiar dietary habits and to determine whether
nutritional intakes are indeed imbalanced, we compared two 7-day food records
for female adolescent athletes from 1 week and 3 weeks before the French Judo
Championship. To assess potential muscle proteolysis in this adolescent athlete
group, nitrogen balance was calculated during each of these weeks from reported
daily protein intake, urine nitrogen excretion, and estimated fecal and integumen-
tal nitrogen losses.
Methods
Participants
Nine healthy adolescent female judo athletes, ages 15–16 years, participated
in this study. All were postpubescent. The participants were trained athletes (at
least 3 years at the national level) and practiced between 10 and 15 hr per week.
Regular Judo training consisted of a repetitive series of short and intense exercises
involving agility and stretching. None of the participants were taking any medica-
tion or supplements during the protocol period. Two out of nine girls were amen-
orrheic for 1 year. The physical and physiological characteristics of the participants
are included in Table 1. Body mass index (BMI) was calculated as weight/height2
and expressed as kg/m2. Percentage of body fat was estimated from skinfold mea-
surements using a Harpenden skinfold caliper (19). Fat free mass was calculated
Table 1 Morphological Characteristics (Means ± SEM) of the Nine Female
Judo Athletes 3 Weeks (W3) and 1 Week (W1) Before Competition
Age Height Weight FFM MM FM BMI
Week (years) (cm) (kg) (kg) (kg) (%) (kg/m2)
W3 16.1 ±0.3 163 ±2 58.9±3.6 45.0 ±1.9 22.2 ±1.2 23.3 ±1.5 22.2 ±1.2
W1 16.1 ±0.3 163 ±2 57.8±3.1* 44.0 ±1.6* 21.8 ±1.1 23.1 ±1.5 21.8 ±1.0*
Note. FFM = fat free mass; MM = estimated muscle mass (21); FM = fat mass; BMI = body mass index:
weight/(height2); fat free mass is calculated from fat mass.
*p < .05 between the 2 weeks.
64 — Boisseau, Vera-Perez, and Poortmans
from fat mass. The girls and their parents were fully informed about this study and
its design, and written consent was obtained following the guidelines of the Medi-
cal Ethics Committee of the Université Libre de Bruxelles.
Measurements
Total energy expenditure and dietary intake. Basal metabolic rate was cal-
culated using the FAO equation (25). To assess their total energy expenditure (TEE),
all participants completed a 7-day questionnaire that comprised questions about
their habitual daily physical activities. The factorial method was used to estimate
TEE (2).
Energy intake was recorded and assessed by a food questionnaire over 7
continuous days 3 weeks (W3) and 1 week (W1) before the competition. The means
for each 7-day period were then calculated. Most foods were weighed before cook-
ing or eating; when food portions were not weighed, models of foods were used to
estimate portion sizes. Before the experimental protocol, a researcher gave de-
tailed information and suggestions on how to fill in the food records. The female
judo athletes were free to consume their regular meals. Detailed descriptions of all
foods and beverages (including brand names) and their method of preparation were
also recorded. The adolescents returned the completed food records to the labora-
tory. On arrival, a researcher queried each adolescent to verify that the dietary
questionnaire had been completed adequately; anthropometric measurements were
also taken at this time. Dietary intakes were analyzed by a trained nutritionist
using Prodiet 5.1 (Proform, France), a professional software program that dis-
plays an analysis of the macro- and micronutrients of selected foods.
Nitrogen balance.We estimated nitrogen balance (NB) 3 weeks and 1 week
before the competition in order to verify potential muscular protein use (through a
negative nitrogen balance) because it is well known that NB can fluctuate in rela-
tion with energy-to-protein ratio changes. Nitrogen balance (24 hr) was determined
from a single pooled urine sample for each adolescent during the last day of
the 7-day food record. The complete urine volume (24 hr) was collected. The
volume-weighted samples from each collection were combined for each par-
ticipant.
Urine was collected in bottles we provided that contained 15 ml hydrochlo-
ric acid 6M to preserve urinary ammonia. In order to validate the completeness of
the 24 hr urine collections, 4-aminobenzoic acid (200 mg capsule of PAB) was
ingested with water by each participant in the morning after voiding. Three weeks
(W3) and 1 week (W1) before the competition, urine was collected on a training
day (the fourth day of the dietary assessment). Total nitrogen content of the urine
was determined in duplicate using a micro-Kjeldhal technique (Büchi Nitrogen
Determination System, Switzerland). Apparent nitrogen balance was estimated by
subtracting urine nitrogen output from dietary nitrogen intake predicted from the
diet data. For practical reasons, fecal and integumental nitrogen losses were not
collected from our athletes. Generally, daily sweat and fecal losses amount to ap-
proximately 12 and 22 mg/kg of body weight, respectively, in adolescents (12).
These values of estimated integumental and fecal losses were used to correct for
inconsistencies in the nitrogen intake and urinary nitrogen loss data in the present
investigation. The apparent nitrogen balance was established using the daily pro-
tein intake corresponding to the day of the urine collection.
Nutritional Aspects in Young Female Athletes — 65
Statistical Analysis
All statistical analyses were performed by the Statistica® software program
for Windows®. Statistical analysis comparing the 2 weeks covered by the ques-
tionnaires was performed using the nonparametric Wilcoxon test. All data are pre-
sented as means ± standard errors of the mean (SEM); p values < .05 were consid-
ered statistically significant.
Results
Table 1 indicates the morphological data of the female adolescent judo ath-
letes. As compared with classical data obtained in healthy 16-year-old girls (23),
the mean weight of our participants was slightly above the range of a normal popu-
lation (normal range: 163 cm, 55 kg). The mean weight loss between the 2 weeks
was 1.1 kg ± 0.5 (–2% of body weight). The BMI and fat free mass were altered by
the restricted diet (–2% and –2%, respectively). No significant differences were
observed between W3 and W1 for fat mass (%) or estimated muscle mass.
As shown in Table 2, daily energy intake (EI), expressed as kcal (or kJ),
decreased 19.7% in W1. During that week, the EI was lower than that recom-
mended for girls of 16 years of age (2,23) and did not compensate for estimated
TEE. No difference in TEE was observed between the 2 weeks studied.
The relative distribution of total carbohydrates was not different between
W3 and W1, but the absolute amount of carbohydrates consumed (in g) was 24%
lower in W1. Expressed in g/day, the total lipid intake and the polyunsaturated and
saturated fatty acid fractions were reduced in W1. The proportion of lipid and
polyunsaturated fatty acids, however, was not different between the 2 weeks. The
fraction of saturated fats decreased by 7.5%, and the monounsaturated fat propor-
tion was increased by 10.5% (p < .05) on W1. Even so, monounsaturated fat was
still under the usual recommended allowance (2). There was no difference in the
total intake of protein between the 2 weeks (± 63 g, or 1.1 g·kg-1·day-1) and the
intake was greater than the recommended daily protein allowance (44g, or
0.8g·kg-1·day-1). The animal/vegetal protein ratio showed an increase of meat con-
sumption during W1.
Daily intake of minerals, vitamins, and fiber were no different 3 weeks and
1 week before competition (Table 3). The adolescents had a lower daily intake of
calcium, magnesium, iron, zinc, copper, iodine, vitamin E, and fiber as compared
with the recommended values for a normal population (2,17,18,23).
Table 4 shows the water consumption and urinary excretion 3 weeks and 1
week before the French judo Championship. Water intake was reduced during W1
because of restricted drink consumption (–8.5%). Accordingly, urinary excretion
was lower (–58%) during W1. Apparent nitrogen balances were not different be-
tween W3 and W1 (Table 5), which corresponded to similar protein intake for the
2 weeks.
Discussion
The objective of this study was to shed light on the dietary habits of female
adolescent judo athletes 3 weeks and 1 week before the French Judo Championship
and to assess unbalanced nutritional intakes and potential muscular proteolysis in
66 — Boisseau, Vera-Perez, and Poortmans
Table 2 Reported Mean Daily Energy Intake, Energy Expenditure, and
Relative Nutrient Distribution (Means ± SEM) in Nine Female Adolescent
Judo Athletes 3 Weeks (W3) and 1 Week (W1) Before Competition
Normal
Parameters W3 W1 Difference range
Energy intake
kcal/day 2,076 ±206 16,66 ±156 p < .01 2,000–2,500b
(kJ/day) (8,679 ±861) (6,963 ±651) p < .01 (8,360–10,400)b
kcal·kg–1 day–1 35.5 ±2.6 28.8 ±2.1 NS
(kJ·kg–1 day–1)(148 ±11) (120 ±89) NS
Basal metabolism
kcal/day 1,436 ±32 1,428 ±27 p < .05 1,500–1,600c
(kJ/day) (6,009 ±132) (5,975 ±112) NS
Total energy
expenditurea
kcal/day 2,544 ±52 2,607 ±134 NS
(kJ/day) (10,633 ±246) (10,897 ±187) NS
kcal·kg–1 day–1 43.2 ±2.1 45.1 ±2.0 p < .05
(kJ·kg–1 day–1) (180 ±10) (188 ±19) p < .05
Proteins (%) 12.3 ±0.5 15.2 ±0.9 p < .05 15%d
g/day 65.6 ±8.2 61.7 ±4.5 NS
g·kg-1·day-1 1.12 ±0.12 1.07 ±0.1 NS 0.8–1.0d, b
animal/vegetal (g) 1.61 ±0.18 2.75 ±0.26 p < .01 > 1d
Lipids (%) 34.9 ±2.1 35.3 ±2.5 NS 30%d
g/day 81.8 ±10.9 66.7 ± 8.9 p < .01
Fatty acids (%)
saturated 45.2 ±1.1 41.9 ±1.8 p < .05 25%d
monounsaturated 39.4 ±1.1 43.5 ±1.7 p < .05 60%d
polyunsaturated 15.0 ±0.6 14.3 ±0.8 NS 15%d
Cholesterol 305 ±51 225 ±38 p < .01
Carbohydrates (%) 52.8 ±2.4 49.4 ±2.3 NS 55%d
g/day 259.5 ±22.5 197.2 ±19.6 p < .01
Simple sugars
(% of EI) 26.9 ±2.1 26.1 ±1.9 NS 10%d
Note. FA = fatty acids; EI = energy intake.
aDaily energy means from a 7-day survey (8); bsource: Recommended Dietary Allowances
in Normal Children 16 to 19 years old (2);csource: Basal Metabolism for Normal Girls 16
Years old (7); dsource: Normal Distribution of Nutrients (8).
*p < .05 (significant differences between the 2 weeks); **p <.01 (significant differences
between the 2 weeks); NS: no significant differences between the 2 weeks.
Nutritional Aspects in Young Female Athletes — 67
Table 3 Daily Dietary Intake of Minerals, Fiber, and Vitamins 3 Weeks (W3)
and 1 Week (W1) Before Competition for Nine Female Judo Athletes
(Means ± SEM)
Normal
Parameters W3 W1 rangea
Calcium (mg) 966 ±94 860 ±66 1,200
Phosphorus (mg) 1,138 ±11 1,046 ±63 800
Magnesium (mg) 261 ±27 227 ±19 370
Iron (mg) 10.3 ±1.1 10.41 ±1.4 16
Zinc (µg) 5.9 ±0.7 6.5 ±0.9 10
Copper (mg) 1.19 ±0.10 1.01 ±0.08 1.5
Iodine (µg) 63.5 ±1112 100.9 ±9.7 120
Thiamin (mg) 1.09 ±0.09 1.19 ±0.15 1.1
Riboflavin (mg) 1.76 ±0.20 1.75 ±0.20 1.5
Vitamin B6 (mg) 1.44 ±0.15 1.74 ±0.21 1.5
Vitamin B12 (µg) 4.37 ±0.64 4.42 ±0.52 2.0
Folate (µg) 244 ±30 270 ±32 200
Vitamin B5 (mg) 4.2 ±0.4 4.0 ±0.3 4.5
Niacin (mgEN) 11.35 ±1.27 14.34 ±2.11 11
Vitamin A (µgER) 676 ±122 633 ±33 600
Vitamin D (µg) 10.23 ±1.22 10.11 ±1.07 5
Vitamin C (mg) 99.1 ±18.4 127.6 ±19.2 110
Vitamin E (mg) 6.59 ±0.86 6.43 ±0.75 12
Total fiber (g) 14.15 ±1.40 12.51 ±0.95 25-35
Note. Values in bold are below the normal range; no differences appeared between the 2
weeks.
aSource: Recommended Dietary Intakes in normal girls of 15–16 years old (2,10,11,20).
Table 4 Daily Water Consumption and Urinary Excretion 3 Weeks (W3) And
1 Week (W1) Before Competition for Nine Female Judo Athletes (Means ±
SEM)
Parameters W3 W1 p
Water consumption (L) 4.22 ±0.41 3.87 ±0.18 < .01
from drinks 1.90 ±0.14 1.55 ±0.13 < .05
from food 2.32 ±0.09 2.36 ±0.12 NS
Urinary excretion (ml) 1,705 ±358 709 ±89 NS
68 — Boisseau, Vera-Perez, and Poortmans
Table 5 Protein Intake, Nitrogen Excretion, and Nitrogen Balance 3 Weeks
(W3) And 1 Week (W1) Before Competition for Nine Female Judo Athletes
(Means ± SEM)
Parameters W3 W1 p
Total protein intakea
g/dayb65.8 ±11.2 62.4 ±4.6 NS
(g/kg·bodyweight/day) 1.12 ±0.18 1.10 ±0.10 NS
N (g/day) 10.53 ±1.79 9.98 ±0.73 NS
Total N excretion*
g/day 9.68 ±1.16 10.89 ±0.83 NS
Apparent N balance
g/day 0.85 ±0.43 –0.92 ±0.64 NS
(g/kg bodyweight/day) 0.02 ±0.02 –0.02 ±0.01 NS
Note. N = nitrogen.
aCalculated from Prodiet 5.1 (software; Nutriform, France); bthe normal range in girls of 15–
16 years old is 44 g (2).
*Protein is assumed to be 16% N.
this population. In order to qualify for their weight class, the athletes had to rely on
restricted food and fluid intakes the week before the weigh-in of the competition.
Our study showed that lean body mass and fat mass were not significantly altered
by weight cutting. Apparently, the observed weight loss was predominantly linked
to an acute dehydration process.
Judo is a dynamic sport that requires complex skills and tactical excellence
for performance. It is characterized by repeated short-duration high-intensity in-
termittent efforts that last approximately 8 min per competition (22). Thus, judo
requires a high degree of aerobic and anaerobic conditioning (24). The estimated
TEE in female adolescent judo athletes was similar 3 weeks and 1 week before the
competition. When expressed as kcal·kg-1·day-1, however, the TEE was greater in
W1. The dietary intake was assessed by a 7-day food-record questionnaire to-
gether with interviews. The intake information for the questionnaire was obtained
by weighing most food portions. During the week before the competition, 8 of 9
participants had to lose weight (a mean loss of about 2.3 kg) in order to qualify for
their weight class. Thus, the restricted food intake in W1 was clearly a decision
made deliberately by the athletes.
The nutritional intakes indicated unbalanced carbohydrate and lipid propor-
tions in W3 and W1. The protein intake (% of EI) was slightly insufficient in W3
(about 12%) but well adapted in W1 (15%). The recommended distribution of
macronutrients in adolescent athletes represents 55– 60% of the total energy for
carbohydrates, 25–30% for lipids, and 15% for proteins (20). The relative percent-
age of carbohydrates in W3 (53%) seemed to be sufficient to maximize glycogen
Nutritional Aspects in Young Female Athletes — 69
storage (9). In W1, however, both the percentage and the total amount of carbohy-
drate were reduced (–6.5%), and they were lower than the recommended allow-
ances (2). Furthermore, as previously reported in adolescent athletes (7), simple
sugar intake was much higher in our adolescent girls (26% instead of the recom-
mended 10%), whereas carbohydrates with a low glycemic index (complex carbo-
hydrates) were in deficit. Thus, the restricted diet in W1 might induce a significant
decrease in muscle and liver glycogen content just before the competition. The
mean daily fiber intake was not different between the time periods and reached
12.5–14 g/day, which is lower than the recommended allowances.
The fat proportion ingestion was not different between W3 and W1 (35% of
the total EI). The total amount of lipids (g), however, decreased (–18.5%) in W1.
Despite a more predominant use of fat during exercise in children (6), there is no
data suggesting that children need greater lipid intakes than do adults. Therefore,
lipids are probably overconsumed as compared with complex carbohydrates in
both W3 and W1. Incidentally, the relative proportion of mono-, polyunsaturated,
and saturated fatty acids was better adapted in W1.
The proportion of protein ingested was higher in W1 than W3 (15% of EI in
W1 compared with 12% in W3). When expressed in g/day, however, the total
amount of protein ingested was similar in W3 and W1. The proportion of animal
protein to vegetal protein ingested increased 71% from W3 to W1, indicating a
significant increase in animal protein consumption. Protein during both weeks was
25% greater than the recommended allowance (1.1 g·kg-1·day-1 vs. 0.8 g·kg-1·day-1;
2,22). As a consequence, the apparent nitrogen balance was positive during the 2
weeks studied and probably indicated no muscular protein use before the compe-
tition (0.85 ± 0.43 and –0.92 ± 0.64 in W3 and W1, respectively). This result
suggests that the amount of protein ingested would prevent proteolysis before the
competition. This might explain the stability in estimated muscle mass even with
the restricted W1 diets of our adolescent female judo athletes.
In physically active children, the daily food ration must provide vitamin B6,
vitamin D, iron, calcium, phosphorus, and magnesium in order to promote growth
and sustain a high level of physical activity (4,5). In our study, there were no
significant differences between W3 and W1 in mineral, vitamin, and fiber intakes.
Calcium, magnesium, iron, zinc, copper, iodine, and vitamin E intakes, however,
were under the recommended allowances for female adolescents of 15–16 years of
age (2,16,17,18). Thus, even in a standard training week without weight cutting
(W3), some deficiencies appeared in our adolescents’ diets that might be prejudi-
cial for their development, maturation, and performance.
The expected benefit of diet restriction in judo athletes appears to be a rapid
weight loss that allows the athletes to qualify to fight in a specific category. Conse-
quently, not only are food intake restrictions imposed on the participants, but flu-
ids are restricted as well. Moreover, during the week just before the competition, 8
out of 9 judo athletes in our study used plastic underwear under their judo suit to
stimulate water loss. Saunas, cathartics, and vomiting, however, were not used.
The mean weight loss in our study was 1.09 ± 0.50 kg. The percentage of fat mass
did not change between W3 and W1, but the fat free mass was reduced by 2.2%.
An unaltered skeletal muscle mass in W1, which was shown by the nitrogen bal-
ance results and the estimation of total skeletal muscle mass (15), provided evi-
dence that the weight loss was related to acute dehydration in these adolescent
70 — Boisseau, Vera-Perez, and Poortmans
female judo athletes. In our study the total amount of urinary excretion was
significantly reduced in W1 as compared with W3 (down 58%). Lower urine vol-
ume excretion and greater sweat production because of the plastic suits worn during
physical training were indications of dehydration. The technique of fluid deprivation
and sweating are well known by athletes competing in a weight-class sport (13).
Our judo athletes practiced these weight-loss strategies in order to remain in
their weight category, hoping for better success. Ironically, weight cutting might
impair performance and endanger the judoka’s health. In our study, weight loss
could probably be attributed to reduction in body water and glycogen storage.
Food and drink restrictions induce a combined negative effect on physical and
psychological capacities. Judo athletes attempt to replenish body fluids, electro-
lytes, and glycogen in the brief period (1–3 hr) between the weigh-in and the
competition. Reestablishing fluid homeostasis and replenishing muscle glycogen,
however, might take 24–48 hr (23) or even longer (11,14). Thus, cutting weight
appears to adversely affect the judoka’s energy reserves and fluid and electrolytes
balances and could alter performance.
The effects of rapid weight loss and dehydration on physiological perfor-
mance are well documented (1). This practice could cause several things: a reduc-
tion in muscle strength and anaerobic power capacity; increased resting and
submaximal heart rate; decreased cardiac stroke volume resulting in decreased
ability to sustain work at a constant rate; lower oxygen consumption; impaired
thermoregulatory processes; lower plasma and blood volume; depletion of muscle
and possibly liver glycogen; difficulty of glucose homeostasis; altered hormonal
status; reduced immune function; and so forth. (1). For all of these reasons, it
seems important to educate coaches and judo athletes in sound nutrition and weight
control practices and to curtail weight cutting in order to avoid adverse effects in
young participants’ growth and maturation. Scientists, physicians, dieticians,
coaches, athletic administrators, trainers, and other health professionals should
work together to change the attitudes that support practices harmful to the athletes.
Acknowledgment
The authors would like to thank our participants and their coach, Bruno, for their
generous cooperation throughout the study. We would also like to thank Pr. A. Denjean for
his kind contribution. Finally, special thanks to Mrs. F. Reding for her skillful assistance
with the Kjeldhal analyses.
References
1. American College of Sports Medicine. Position stand on weight loss in wrestlers. Med.
Sci. Sports Exerc. 28(2):ix-xii, 1996.
2. ANC. Apports Nutritionnels Recommandés (ANC) Pour la Population Française. Paris:
Tec & Doc, 2001.
3. Bar-Or, O. Nutritional considerations for the child athlete. Can. J. Appl. Physiol.
26(Suppl):S186-91, 2001.
4. Beals, A. Nutritional Concerns of Adolescent Athletes. Washington: CRC, 2001.
5. Beaufrère, B., A. Briend, J. Ghisolfi, et al. Nourissons enfants et adolescents. In: Apports
Nutritionnels Conseillés Pour la Population Française. Tec and Doc (Ed.). Paris: Tec
& Doc, 2001, pp. 253-305.
Nutritional Aspects in Young Female Athletes — 71
6. Boisseau, N., and P. Delamarche. Metabolic and hormonal responses to exercise in
children and adolescents. Sport Med. 30(6):405-422, 2000.
7. Boisseau, N., C. Le Creff, M.P. Loyens, and J.R. Poortmans. Protein intake and nitro-
gen balance in male non-active adolescents and soccer players. Eur. J. Appl. Physiol.
88:288-293, 2002.
8. Brownell, K., S.N. Steen, and J.H. Wilmore. Weight regulation practices in athletes:
analysis of metabolic and health effects. Med. Sci. Sports Exerc. 19(6):546-556, 1987.
9. Costill, D.L., W.M. Sherman, W.J. Fink, C. Maresh, M. Witten, and J.M. Miller. The
role of dietary carbohydrate in muscle glycogen resynthesis after strenuous running.
Am. J. Clin. Nutr. 34:1831-1836, 1981.
10. Costill, D.L., P. Cote, and W.J. Fink. Rapid fluid replacement following thermal dehy-
dration. J. Appl. Physiol. 34:299-303, 1973.
11. Coyle, E.F., and E. Coyle. Carbohydrates that speed recovery from training. Phys.
Sportsmed. 21:111-123, 1993.
12. Egun, G.N., and T. Atnimo. Sweat nitrogen losses of young adult females in Nigeria
with different levels of dietary protein intake. Nutr. Res. 12:199-208, 1992.
13. Horswill, C.A., R.C. Hickner, J.R. Scott, D.L. Costill, and D. Gould. Weight loss,
dietary carbohydrate modifications, and high intensity, physical performance. Med.
Sci. Sports Exerc. 22 470-476, 1990.
14. Hultman, E., and L. Nilsson. Liver glycogen as glucose-supplying source during exer-
cise. In: Limiting Factors of Physical Performance. J. Keul and G. Thieme (Eds.).
Stuttgart: Georg Thieme, 1973, pp. 2-62.
15. Lee, R.C., Z. Wang, M. Heo, R. Ross, I. Janssens, and S.B. Heymsfield. Total-body
skeletal muscle mass: development and cross-validation of anthropometric prediction
models. Am. J. Clin. Nutr. 72:796-803, 2000.
16. National Academy of Sciences. Dietary Reference Intakes for Calcium, Phosphorus,
Magnesium, Vitamin D, and Fluoride. Washington: The National Academies Press, 1999.
17. National Academy of Sciences. Dietary Reference Intakes for Vitamin A, Vitamin K,
Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel,
Silicon, Vanadium, and Zinc. Washington: The National Academies Press, 2002.
18. National Academy of Sciences. Dietary Reference Intakes for Thiamin, Riboflavin,
Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Wash-
ington: The National Academies Press, 2000.
19. Pariskova, J. Total body fat and skinfold thickness in children. Metabolism. 10:794-
807, 1961.
20. Probart, C.K., P.J. Bird and K.A. Parker. Diet and athletic performance. Clin. Nutr.
77:757-772, 1993.
21. Rogol, A.D., P.A. Clark, and J.N. Roemmich. Growth development in children and
adolescents: effects of diet and physical activity. Am. J. Nutr. 72(suppl):521S-528S,
1990.
22. Sikorski, M., B. Mickiewicz, and C. Maole. Structure of the contest and work capacity
of the judoist. Warshaw: Polish Judo Association Institute of Sports, 1987.
23. Subcommittee on the 10th Edition of the RDAs, Food and Nutrition Board, Commis-
sion on Life Sciences, National Research Council. Commission on Life Sciences Rec-
ommended Daily Allowances, 10th ed. Washington: The National Academies Press,
1989.
24. Thomas, S.G., M.H. Cox, Y. Legal, T.J. Verde, and H.K. Smith. Physiological profiles
of the Canadian National Judo Team. Can. J. Sport Sci. 14(3):142-147, 1989.
25. World Health Organisation, the Food and Agriculture Organization of the United Na-
tions, and the United Nations University. Energy and protein requirements. Geneva:
World Health Organisation, 1985.
