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The Effect of Individual Sodium Citrate Consumption on Repeated Sprint Performance in Female Soccer Players

The Acute Effects of Individually Timed Sodium Citrate Ingestion on Repeated Sprint Performance in Professional Female Soccer Players: A Randomized, Double-Blind, Placebo-Controlled Crossover Study

Status
Not yet recruiting
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07737327
Acronym
ITSCORE-F
Enrollment
20
Registered
2026-07-30
Start date
2026-08-20
Completion date
2027-02-01
Last updated
2026-07-30

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Exercise-Induced Fatigue, Athletic Performance, Soccer

Keywords

Sodium citrate, Buffering agent, Repeated sprint performance, Female athletes, Soccer, Anaerobic performance, Blood bicarbonate, Individualized timing

Brief summary

The aim of this research is to determine whether sodium citrate supplementation, taken at the best individual time, would improve repeated sprint performance in professional female soccer players. The main questions it aims to answer are: 1. Does sodium citrate improve sprint times, peak power, minimum power, and mean power during repeated sprints? 2. Does sodium citrate lower fatigue index (the drop in power across sprints) during repeated sprint exercise? 3. Does sodium citrate change blood bicarbonate, pH, and lactate levels before and after exercise? 4. Does sodium citrate affect how hard exercise feels (perceived exertion)?

Detailed description

This study is a randomized, double-blind, placebo-controlled crossover trial designed to investigate the effects of acute sodium citrate (SC) supplementation on repeated sprint performance and acid-base responses in female soccer players. Based on an a priori sample size calculation using G\*Power (version 3.1), a minimum of 20 participants is required and will be recruited. Eligible participants will be professional female soccer players competing in the Turkish Women's Third League. Each participant will complete two experimental trials in a randomized order, separated by a washout period of at least three days. During the SC trial, participants will ingest SC at a dose of 0.5 g·kg-¹ body mass dissolved in a flavored beverage. During the placebo (PL) trial, participants will consume a taste- and appearance-matched sodium chloride solution. Both supplements will be prepared by a researcher not involved in data collection to ensure allocation concealment and maintenance of double blinding. On each experimental visit, participants will arrive at the laboratory following an overnight fast and will consume a standardized breakfast before supplementation. Capillary blood samples will be collected before supplementation and at regular intervals thereafter to determine blood bicarbonate concentration. During the SC condition, exercise testing will commence once blood bicarbonate concentration has increased by at least 5.0 mmol·L-¹ above baseline (individualized peak bicarbonate response; Tpeak). During the placebo condition, exercise testing will begin 120-150 minutes after ingestion, corresponding to the expected time window for peak bicarbonate responses observed during SC supplementation. To minimize the influence of hormonal fluctuations on exercise performance and physiological responses, both experimental trials will be conducted during the same phase of the menstrual cycle, outside the menstruation period. Participants using oral contraceptives will be excluded. Repeated sprint performance will be assessed using the Running-based Anaerobic Sprint Test (RAST), which consists of six maximal 35-m sprints separated by 10 seconds of passive recovery. Sprint performance outcomes will include sprint times, peak power, minimum power, mean power, and fatigue index. Capillary blood samples will be collected at baseline, immediately before exercise, and immediately after exercise to determine blood bicarbonate concentration, blood pH, and lactate concentration. Ratings of perceived exertion (RPE) will be recorded after each sprint using the Borg 6-20 scale. The success of participant blinding will be evaluated using a blinding questionnaire administered at three predefined time points during the study.

Interventions

DIETARY_SUPPLEMENTSodium Citrate Oral Product

0.5 g/kg body weight of sodium citrate dissolved in flavored water, ingested orally. Exercise begins at individual peak blood bicarbonate time (T\_peak), determined through serial capillary blood sampling starting 90 minutes post-ingestion.

OTHERPlacebo

Sodium chloride (NaCl) at a taste-matched dose dissolved in flavored water, ingested orally. Exercise begins 120-150 minutes post-ingestion.

Sponsors

Hacettepe University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)

Masking description

The lead researcher managed randomization and was not involved in blood sampling or performance testing. Participants and the blood-sampling investigator were blinded to treatment allocation.

Intervention model description

Each participant will complete both the sodium citrate and placebo trials in a randomized order, with a washout period of at least three days between trials.

Eligibility

Sex/Gender
FEMALE
Age
18 Years to 25 Years
Healthy volunteers
Yes

Inclusion criteria

* Female professional soccer players competing in the Turkish Women's Third League * Age between 18-25 years * Active training status (minimum 3 sessions per week) * Regular menstrual cycles * Both experimental trials scheduled in the same phase of the menstrual cycle, outside of menstruation * No use of nutritional supplements in the 4 weeks prior to the study * Willingness to provide written informed consent

Exclusion criteria

* Use of oral contraceptives * Irregular menstrual cycle * History of gastrointestinal disorders * Any musculoskeletal injury preventing maximal sprint performance * Smoking * Use of any medication that may affect acid-base balance * Pregnancy

Design outcomes

Primary

MeasureTime frameDescription
Minimum PowerMeasured during the RAST test, administered immediately after the individualized ingestion-to-exercise interval (T_peak for sodium citrate; 120-150 minutes post-ingestion for placebo)The lowest power output recorded across six maximal 35-meter sprints during the Running-based Anaerobic Sprint Test (RAST). Calculated as body weight (kg) multiplied by the square of sprint distance (m) divided by the cube of the slowest sprint time (s).
Fatigue IndexMeasured during the RAST test, administered immediately after the individualized ingestion-to-exercise interval (T_peak for sodium citrate; 120-150 minutes post-ingestion for placebo)The rate of power decline across six maximal 35-meter sprints during the Running-based Anaerobic Sprint Test (RAST). Calculated as the difference between peak power and minimum power divided by total sprint time (W/s).

Secondary

MeasureTime frameDescription
Peak PowerMeasured during the RAST test, administered immediately after the individualized ingestion-to-exercise interval (T_peak for sodium citrate; 120-150 minutes post-ingestion for placebo)The highest power output recorded across six maximal 35-meter sprints during the Running-based Anaerobic Sprint Test (RAST). Calculated as body weight (kg) multiplied by the square of sprint distance (m) divided by the cube of the fastest sprint time (s).
Mean PowerMeasured during the RAST test, administered immediately after the individualized ingestion-to-exercise interval (T_peak for sodium citrate; 120-150 minutes post-ingestion for placebo)The average power output recorded across six maximal 35-meter sprints during the Running-based Anaerobic Sprint Test (RAST). Calculated as the mean of all six individual sprint power values.
Sprint TimesMeasured during the RAST test, administered immediately after the individualized ingestion-to-exercise interval (T_peak for sodium citrate; 120-150 minutes post-ingestion for placebo)Individual sprint times recorded for each of the six maximal 35-meter sprints during the Running-based Anaerobic Sprint Test (RAST), measured in seconds using a photoelectric timing system.
Blood Bicarbonate ConcentrationMeasured at baseline (pre-ingestion), pre-exercise (at T_peak for sodium citrate; 120-150 minutes post-ingestion for placebo), and at 1, 3, 5, and 7 minutes post-exercise.Capillary blood bicarbonate concentration (HCO₃-, mmol/L) measured at baseline, pre-exercise, and post-exercise using a portable blood gas analyzer.
Blood pHMeasured at baseline (pre-ingestion), pre-exercise (at T_peak for sodium citrate; 120-150 minutes post-ingestion for placebo), and at 1, 3, 5, and 7 minutes post-exercise.Capillary blood pH measured at baseline, pre-exercise, and post-exercise using a portable blood gas analyzer.
Blood Lactate ConcentrationMeasured at baseline (pre-ingestion), pre-exercise (at T_peak for sodium citrate; 120-150 minutes post-ingestion for placebo), and at 1, 3, 5, and 7 minutes post-exercise.Capillary blood pH measured at baseline, pre-exercise, and post-exercise using a portable blood gas analyzer.
Rating of Perceived Exertion (RPE)Measured after each sprint during the RAST test, administered immediately after the individualized ingestion-to-exercise interval (T_peak for sodium citrate; 120-150 minutes post-ingestion for placebo)Perceived exertion rated by participants after each of the six maximal 35-meter sprints using the Borg RPE scale (6-20).

Contacts

CONTACTDilara KURU, PhD Candidate
dytdilarakuru@gmail.com+905317242084
CONTACTHüseyin Hüsrev TURNAGÖL, Professor
husrevturnagol@gmail.com+905323975259
PRINCIPAL_INVESTIGATORHüseyin Hüsrev TURNAGÖL, Professor

Hacettepe University, Faculty of Sport Sciences

PRINCIPAL_INVESTIGATORMuhammed M Atakan, Associate Professor

Hacettepe University

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jul 31, 2026