The DOI matches its Crossref record; 41 of the 42 references it cites were found in a registry or an index; none of the 8 sources its claims cite is checked for support yet.
Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day
Open accessAbstract
Despite numerous studies related to dehydration there is still a lack of scientific literature presenting hydration status and fluid intake of judo athletes during different periods. Therefore, the aim of this study was to investigate, fluid intake, hydration status and body weight changes of young judo athletes during a typical day of training in preparation period. Twenty-two young judo athletes (age: 12 ± 0.7 y, experience: 3.5 ± 1.1) voluntarily participated in this study. Hydration status and weight were examined in the morning, before and immediately after the training. All athletes trained 90 min and they consumed fluids ad libitum during the exercise. According to morning urine specific gravity (USG) values, 81.2% of the athletes were dehydrated while only 18.8% of the athletes were euhydrated. Pre-training urine measurements showed that 63.64% of the athletes presented dehydration and 77.27% of the athletes completed the training in dehydrated condition despite fluid availability during the training. Mean body weight loss during training was -0.64 ± 0.66%. It can be concluded that young judo athletes presented high prevalence of dehydration as indicated by USG values. Most of the athletes were dehydrated during a typical training day and completed the training in more dehydrated conditions compared to pre training values despite ad libitum fluid intake. It is of great importance to evaluate hydration status of the athletes before training to refrain from common practice of fluid restriction for weight loss and adverse effects of a persistent state of fluid deficit on physical and health related state.
Overview
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TL;DR
In 22 U-15 Turkish judo athletes during a 90-min preparatory-phase training day, most were dehydrated by morning urine specific gravity (USG) and remained or became more dehydrated post-training despite ad libitum fluid access. Body weight decreased significantly across the day, with a mean training loss of 0.64 ± 0.66%.
Key findings
- Morning USG showed 81.2% dehydrated and 18.8% euhydrated; pre-training, 63.64% were dehydrated, and 77.27% completed training dehydrated despite fluid availability.
- USG did not differ significantly across morning, pre-training, and post-training (F1-21 = 1.60; p = 0.22; ES = 0.071 [small effect]); values were 1.022 ± 0.005, 1.023 ± 0.004, and 1.024 ± 0.004, respectively.
- Body weight differed significantly among measurements (F1-21 = 13.52, p < 0.000; table p = 0.001), with differences between pre-training and post-training (p = 0.000) and between morning and post-training (p < 0.01); mean weight loss during training was 0.64 ± 0.66% (−0.27 kg).
- No significant correlations were found between fluid intake and body weight change percentage (r = 0.18 [small]; p = 0.43; 95% CI = −0.56 to 0.27) or between fluid intake and USG change percentage (r = −0.15 [small]; p = 0.52; 95% CI = −0.53 to 0.29).
Methods
- Descriptive study of 22 U-15 regional/national-level Turkish judo athletes (reported as 14 males and 7 females; age 12 ± 0.7 y; judo experience 3.5 ± 1.1 y) during a typical 90-min preparatory-phase training session; fluids were consumed ad libitum, and athletes were not informed about the nature of the study. Training hall conditions were 28.3°C and 56% humidity.
- Measurements were taken in the morning, before training, and immediately after training: hydration status via USG using a digital refractometer (euhydrated defined as USG ≤ 1.020 g mL⁻¹), body weight, body composition by bioelectrical impedance, and stature by stadiometer; percentage weight loss was calculated according to Scott, Horswill, and Dick (1994).
- Analysis used one-way repeated-measures ANOVA with Tukey HSD post-hoc tests, Pearson product correlations, SPSS 20, and significance set at p < 0.05.
Limitations
- The paper states it did not control potential effects on USG such as prior training or supplement use, and that the study was primarily limited by the small number of athletes.
- The paper states future studies are warranted to present the real effects of dehydration on judo performance at all competitive age groups.
- Evident from the text: the reported sample of 22 athletes is inconsistent with the listed “14 males and 7 females” (21 athletes), and no absolute fluid intake values are reported despite fluid intake being monitored.
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Claims the paper makes
0 Valid · 0 Not valid · 7 Not checked · 15 Own results and interpretations
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Pre-training urine measurements showed that 63.64% of the athletes presented dehydration”
- Also stated in: § Results · plain
“In view of pre-training USG measurements, they displayed that 63.64% of the athletes presented dehydration.”
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Abstract
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Also stated in: § Results · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Considering the USG values comparison (among the morning, pre and post training outcomes), there were no significant differences (F1-21=1.60;p=0.22;ES=0.071 [small effect]) (Table 3).”
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Results
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“77.27% of the athletes completed the training in dehydrated condition despite fluid availability during the training.”
- Also stated in: § Results · plain
“Despite fluid availability of all athletes during the training 77.27% of the athletes completed the training in dehydrated condition.”
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Abstract
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Also stated in: § Results · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Mean body weight loss during training was -0.64 ± 0.66%.”
- Also stated in: § Results · plain
“weight loss percentage during the training was 0.64 ± 0.66% (-0.27 kg) (Figure 2)”
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Abstract
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Also stated in: § Results · plain
None of the sources cited for this claim have been checked yet.
In the paper
“USG is accepted as a valid and reliable way of monitoring hydration status (Cheuvront & Sawka, 2005;Meyer et al., 2016)”
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Discussion
What the sources say
- Not matchedcites Cheuvront & Sawka, 2005
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
- Not checked yetcites Meyer et al., 2016 source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
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Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
Each contradiction between two passages listed here was confirmed by an independent check.
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Discussion
“presented elevated first morning USG samples (USG < 1.020), which proved that the athletes adopted inadequate rehydration habits outside practice”
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Measurements
“USG values were classified as USG of ≤ 1020 g mL -1 is indicative of being euhydrated (Popowski et al., 2001).”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
“Twenty-two (14 males and 7 females) under-15 regional and national level Turkish judo athletes (12±0.7 years) agreed to participate in the project.”
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Participants
Reported 22 · recomputed 21
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Results
“there were no significant differences (F1-21=1.60;p=0.22;ES=0.071 [small effect])”
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Statistical analysis
“A oneway analysis of variance with repeated measures (ANOVA) was performed to assess changes in the dependent variables (USG and total body weight) using time (morning, pre and post training) as the factor.”
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Results
“According to morning USG values, 81.2% of the athletes were dehydrated while only 18.8% of the athletes were euhydrated (Figure 1).”
§ Fluid intake, hydration status and body mass changes in U-15 judo athletes during a training day > Abstract
“Twenty-two young judo athletes (age: 12 ± 0.7 y, experience: 3.5 ± 1.1) voluntarily participated in this study.”
Citations
Cites
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American College of Sports Medicine Position Stand: Exercise and Fluid Replacement
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Dehydration: Physiology, Assessment, and Performance Effects
Cheuvront, S. N., & Kenefick, R. W. (2014) · Comprehensive Physiology · doi:10.1002/cphy.c130017 · Cited by 461
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Fluid Balance and Endurance Exercise Performance
Cheuvront, S. N., Carter, R., & Sawka, M. N. (2003) · Current Sports Medicine Reports · doi:10.1249/00149619-200308000-00006 · Cited by 379
Blood and urinary measures of hydration status during progressive acute dehydration
POPOWSKI, L. A., OPPLIGER, R. A., PATRICK LAMBERT, G., JOHNSON, R. F., KIM JOHNSON, A., & GISOLFI, C. V. (2001) · Medicine & Science in Sports & Exercise · doi:10.1097/00005768-200105000-00011 · Cited by 345
Effects of fluid ingestion on cognitive function after heat stress or exercise-induced dehydration
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Prevalence, Magnitude, and Methods of Rapid Weight Loss among Judo Competitors
GIANNINI ARTIOLI, G., GUALANO, B., FRANCHINI, E., SCAGLIUSI, F. B., TAKESIAN, M., FUCHS, M., & LANCHA, A. H. (2010) · Medicine & Science in Sports & Exercise · doi:10.1249/mss.0b013e3181ba8055 · Cited by 325
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Urinary Indices during Dehydration, Exercise, and Rehydration
Armstrong, L. E., Herrera Soto, J. A., Hacker, F. T., Casa, D. J., Kavouras, S. A., & Maresh, C. M. (1998) · International Journal of Sport Nutrition · doi:10.1123/ijsn.8.4.345 · Cited by 306
Research works printed but not linked: 2
- Cian, C., Koulmann, N., Barraud, P. A., Raphel, C., Jimenez, C., & Melin, B. (2000). Influences of variations in body hydration on cognitive function: effect of hyperhydration, heat stress, and exercise-induced dehydration. Journal of Psychophysiology, 14(1), 29-36. DOI: https://doi.org/10.1027/0269-8803.14.1.29 Acta Scientiarum. Health Sciences, v. 44, e57233, 2022 · DOI
- Judelson, D. A., Maresh, C. M., Anderson, J. M., Armstrong, L. E., Casa, D. J., Kraemer, W. J., & Volek, J. S. (2007). Hydration and muscular performance. Sports Medicine, 37(10), 907-921.
Cited by
Acute Dehydration Impairs Performance and Physiological Responses in Highly Trained Judo Athletes
Ceylan, B., Kons, R. L., Detanico, D., & Šimenko, J. (2022) · Biology · doi:10.3390/biology11060872 · Cited by 39
Self-citationPapaoikonomou, G., Apergi, K., & Malisova, O. (2025) · Children · doi:10.3390/children12020171 · Cited by 13
Ceylan, B., Taşcan, M. B., Šimenko, J., & Balcı, Ş. S. (2022) · International Journal of Sports Science & Coaching · doi:10.1177/17479541221122433 · Cited by 8
Self-citationSales, J. M., Gomes, J. H., Matins, B., Resende, C. F., & Mendes, R. R. (2025) · Revista Brasileira de Fisiologia do Exercício · doi:10.33233/rbfex.v24i1.5648
Hydration and hydration monitoring in combat sports
Ceylan, B. (2025) · Buleria (Universidad de León)
Self-citationWidodo, A., Hakim, A. A., Rusdiawan, A., Wismanadi, H., Németh, Z. F., Fithroni, H., Mentari, M. P., & Basri, H. (2026) · Physical Education Theory and Methodology · doi:10.17309/tmfv.2026.1.12
A Study of Kazakh Judokas Hypohydration Levels During Training at a Weight-Stable Period
Ceylan, B., Kabachkova, A. V., Suleyeva, K., Абишев, Ж. Б., Nazarova, A. I., & Dyubanova, S. (2026) · Trends in physical education and sport · doi:10.31489/3081-0531/2026-2-1-3/14-18
Self-citationEski, T., Taşkın, H. B., Karaman, S., & Ceylan, B. (2026) · BMC Sports Science Medicine and Rehabilitation · doi:10.1186/s13102-026-01860-0
Self-citation
Metadata
- Authors
- Ceylan, B., & Santos, L.
- Affiliations
- Kastamonu University (TR)
- ORCID
- Ceylan, Bayram
- Venue
- Acta Scientiarum. Health Sciences
- Publisher
- Universidade Estadual de Maringa
- Published
- 2022-01-17
- Volume
- 44
- Pages
- e57233
- ISSN
- 1679-9291 (ISSN-L)
- 1807-8648
- OpenAlex
- W3186466173
- Cited by
- 8
- References
- 42
- Citations by year
- 2026: 3 · 2025: 3 · 2022: 2
- FWCI
- 0.74
- Type
- journal article
- Language
- en
- Open access
- diamond
- doi.org
- Locations
- Acta Scientiarum Health Sciences (publishedVersion, cc-by)
- Buleria (Universidad de León) (submittedVersion, cc-by-nc-nd)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
- Redalyc (Universidad Autónoma del Estado de México) (submittedVersion)
- Topics
- Health Sciences › Medicine › Physiology (medical) › Thermoregulation and physiological responses
- Social Sciences › Safety Research › Martial Arts: Techniques, Psychology, and Education
- Health Sciences › Medicine › Orthopedics and Sports Medicine › Sports Performance and Training
- Keywords
- dehydration, hydration status, fluid intake, judo athletes, youth athletes, urine specific gravity, weight loss, training day, fluid deficit
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