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NCT Number: NCT07730606

Acute Sodium Bicarbonate Supplementation in Female Basketball Players

This randomized, double-blind, placebo-controlled crossover study aims to evaluate the effect of acute sodium bicarbonate supplementation, compared with placebo, on physical capacity and blood biochemical marker concentrations in highly trained female basketball players.

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Key information

Conditions

Supplementation Sports

Age range

16 year–35 year

Sex eligibility

Female

Study type

Interventional

Phase

Phase 3

Primary location

Department of Sports Dietetics, Poznan University of Physical Education Poznań

Poznan, 61-871, Poland

Location status: Recruiting

Location contact

Jakub Adamczewski, MSc

CONTACT

[email protected]

+48 66 317 56 06

Krzysztof Durkalec-Michalski, PhD

CONTACT

[email protected]

About this study

Sodium bicarbonate (SB) is commonly proposed as an ergogenic aid due to its potential to enhance extracellular buffering capacity, thereby supporting acid-base balance and delaying fatigue during repeated high-intensity exercise. This mechanism may be particularly relevant in basketball, where performance depends on repeated short-duration, high-intensity efforts, rapid recovery between actions, and the ability to maintain power output during demanding phases of play. Although the ergogenic effects of SB supplementation have been widely investigated, existing evidence has primarily focused on male participants, and data regarding highly trained female athletes remain limited. This creates an important knowledge gap, especially in team sports such as basketball, where sex-specific physiological responses, training status, and sport-specific demands may influence the effectiveness and tolerability of supplementation strategies. This study will evaluate the effect of a single dose of SB compared with placebo. Participants will receive SB or placebo in a randomized, double-blind, placebo-controlled crossover design. The SB dose will be 0.3 g/kg body mass, administered 90 minutes before the exercise protocol, with intervention visits separated by a washout period. By using a randomized, double-blind, placebo-controlled crossover design, this study will allow for the evaluation of individual responses to acute SB supplementation under controlled laboratory conditions. The findings may help clarify whether acute SB intake is an effective and tolerable strategy for supporting physical capacity and biochemical responses in highly trained female basketball players.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • female sex,
  • age 16 to 35 years,
  • good general health condition and well-being,
  • regular menstrual cycles,
  • written informed consent to participate in the study before its commencement,
  • at least a high level of training status,
  • at least 4 years of training experience in basketball,
  • participation in at least 3 basketball-specific training sessions per week,
  • participation in at least 1 basketball game per week.

Exclusion criteria

  • male sex,
  • use of hormonal contraceptives,
  • current injury or musculoskeletal condition limiting participation in training or competition,
  • health-related or medical contraindications, including menstrual disorders, planned pregnancy, or anemia,
  • use of supplements within 3 months before the study, except for regular use of protein supplements, carbohydrate supplements, or isotonic drinks,
  • failure to meet the study protocol assumptions or unwillingness to follow study procedures.

Treatment and study plan

Sodium Bicarbonate (NaHCO3)

Dietary Supplement

Sodium bicarbonate supplementation; Participants will receive a single oral dose of sodium bicarbonate (SB) at 0.3 g/kg body mass, administered in opaque gelatin capsules 90 minutes before the exercise protocol during the first intervention visit.

Placebo

Other

Participants will receive a single oral dose of placebo (PL), administered in identical opaque gelatin capsules 90 minutes before the exercise protocol during the first intervention visit.

Primary outcomes

  1. Changes in anaerobic power during the repeated modified Wingate Anaerobic Test

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of peak power (PP), average power (AP), minimum power (MP), and power drop (PD) [W (watts)] during the repeated modified Wingate Anaerobic Test using the Monark 894E cycle ergometer (Monark, Sweden)

  2. Changes in interval mean power during the repeated modified Wingate Anaerobic Test

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of mean power [W (watts)] in predefined 5 second intervals, including 1 to 5 s and 6 to 10 s, during each 10 second effort of the repeated modified Wingate Anaerobic Test using the Monark 894E cycle ergometer (Monark, Sweden)

  3. Changes in second-by-second power output during the repeated modified Wingate Anaerobic Test

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of power output [W (watts)] for each 1 second segment, including 1 s, 2 s, 3 s, 4 s, 5 s, 6 s, 7 s, 8 s, 9 s, and 10 s, during each 10 second effort of the repeated modified Wingate Anaerobic Test using the Monark 894E cycle ergometer (Monark, Sweden)

  4. Changes in time to peak power during the repeated modified Wingate Anaerobic Test

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of time to peak power (TTP) [s (seconds)] during each 10 second effort of the repeated modified Wingate Anaerobic Test using the Monark 894E cycle ergometer (Monark, Sweden)

  5. Changes in countermovement jump height

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of countermovement jump (CMJ) height [cm (centimeters)] during three consecutive CMJ attempts using the OptoJump Next optical measurement system (Microgate, Italy)

  6. Changes in countermovement jump power

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of countermovement jump (CMJ) power [W (watts)] during three consecutive CMJ attempts using the OptoJump Next optical measurement system (Microgate, Italy).

  7. Changes in blood bicarbonate, base excess, anion gap, and lactate concentrations

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of blood bicarbonate, base excess, anion gap, and lactate concentrations [mmol/L] in capillary blood using the ABL90 FLEX PLUS blood gas analyzer (Radiometer, Denmark)

  8. Changes in hydrogen ion concentration

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of hydrogen ion concentration [nmol/L] in capillary blood using the ABL90 FLEX PLUS blood gas analyzer (Radiometer, Denmark)

  9. Changes in pH in blood

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of blood pH [pH units] in capillary blood using the ABL90 FLEX PLUS blood gas analyzer (Radiometer, Denmark)

Secondary outcomes

  1. Changes in oxygen uptake, carbon dioxide production, and minute ventilation during the repeated modified Wingate Anaerobic Test

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of oxygen uptake (VO₂), carbon dioxide production (VCO₂), and minute ventilation (VE) [L/min] during the repeated modified Wingate Anaerobic Test using the K5 wearable metabolic system (Cosmed, Italy)

  2. Changes in relative oxygen uptake during the repeated modified Wingate Anaerobic Test

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of relative oxygen uptake (VO₂), and carbon dioxide production (VCO₂) [mL/kg/min] during the repeated modified Wingate Anaerobic Test using the K5 wearable metabolic system (Cosmed, Italy)

  3. Changes in respiratory exchange ratio during the repeated modified Wingate Anaerobic Test

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of respiratory exchange ratio (RER) [ratio] during the repeated modified Wingate Anaerobic Test using the K5 wearable metabolic system (Cosmed, Italy)

  4. Changes in breathing frequency during the repeated modified Wingate Anaerobic Test

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of breathing frequency (BF) [breaths/min] during the repeated modified Wingate Anaerobic Test using the K5 wearable metabolic system (Cosmed, Italy)

  5. Changes in tidal volume during the repeated modified Wingate Anaerobic Test

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of tidal volume (VT) [L] during the repeated modified Wingate Anaerobic Test using the K5 wearable metabolic system (Cosmed, Italy)

  6. Changes in heart rate during the exercise protocol

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of maximum heart rate (HRmax) and mean heart rate (HRmean) [bpm] during the exercise protocol using the HRM-Dual heart rate monitor (Garmin Ltd., United States)

  7. Changes in rate of perceived exertion

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of rate of perceived exertion (RPE) [Borg scale points] using the 15 point Borg scale, ranging from 6 to 20 points

  8. Changes in gastrointestinal symptoms

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of gastrointestinal symptoms (GI) [NRS points] using a 19 item gastrointestinal symptom questionnaire with an 11 point numerical rating scale, ranging from 0 to 10 points

  9. Changes in body mass, fat-free mass, fat mass, total body water, intracellular water, and extracellular water

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of body mass, fat-free mass, fat mass, total body water, intracellular water, and extracellular water [kg (kilograms)] using the WPT 60/150 OW scale with integrated stadiometer (Radwag, Poland) and the 101 BIVA PRO body composition analyzer (Akern S.r.l., Italy)

  10. Changes in fat-free mass percentage, fat mass percentage, total body water percentage, intracellular water percentage, and extracellular water percentage

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of fat-free mass percentage, fat mass percentage, total body water percentage, intracellular water percentage, and extracellular water percentage [% (percent)] using the 101 BIVA PRO body composition analyzer (Akern S.r.l., Italy)

  11. Changes in white blood cell count, white blood cell subpopulations, red blood cell count, and platelet count

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of white blood cell count, white blood cell subpopulations, red blood cell count, and platelet count [count/L] in capillary blood using the Mythic 18 hematology analyzer (Orphée, Switzerland)

  12. Changes in hemoglobin concentration

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of hemoglobin concentration [mmol/L] in capillary blood using the Mythic 18 hematology analyzer (Orphée, Switzerland)

  13. Changes in hematocrit

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of hematocrit [L/L] in capillary blood using the Mythic 18 hematology analyzer (Orphée, Switzerland)

  14. Changes in alanine aminotransferase, aspartate aminotransferase, creatine kinase, and lactate dehydrogenase activities

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), creatine kinase (CK), and lactate dehydrogenase (LDH) activities [U/L] in capillary blood using the ACCENT-220S biochemical analyzer (PZ Cormay S.A., Poland).

  15. Changes in creatinine concentration

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of creatinine concentration [µmol/L] in capillary blood using the ACCENT-220S biochemical analyzer (PZ Cormay S.A., Poland).

  16. Changes in urea concentration

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of urea concentration [mmol/L] in capillary blood using the ACCENT-220S biochemical analyzer (PZ Cormay S.A., Poland).

  17. Changes in iron, unsaturated iron-binding capacity, and total iron-binding capacity concentrations

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of iron, unsaturated iron-binding capacity (UIBC), and total iron-binding capacity (TIBC) concentrations [µg/dL] in capillary blood using the ACCENT-220S biochemical analyzer (PZ Cormay S.A., Poland).

  18. Changes in ferritin concentration

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of ferritin concentration [ng/mL] in capillary blood using the ACCENT-220S biochemical analyzer (PZ Cormay S.A., Poland).

  19. Changes in transferrin concentration

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of transferrin concentration [g/L] in capillary blood using the ACCENT-220S biochemical analyzer (PZ Cormay S.A., Poland).

  20. Changes in partial pressure of carbon dioxide and oxygen

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of partial pressure of carbon dioxide (pCO₂) and partial pressure of oxygen (pO₂) [mmHg] in capillary blood using the ABL90 FLEX PLUS blood gas analyzer (Radiometer, Denmark).

  21. Changes in oxygen saturation and hemoglobin fractions

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of oxygen saturation (sO₂), oxyhemoglobin fraction (FO₂Hb), carboxyhemoglobin fraction (FCOHb), deoxyhemoglobin fraction (FHHb), and methemoglobin fraction (FMetHb) [% (percent)] in capillary blood using the ABL90 FLEX PLUS blood gas analyzer (Radiometer, Denmark).

  22. Changes in potassium, sodium, ionized calcium, and chloride concentration

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of potassium (K⁺), sodium (Na⁺), ionized calcium (Ca²⁺), and chloride (Cl-) concentrations [mmol/L] in capillary blood using the ABL90 FLEX PLUS blood gas analyzer (Radiometer, Denmark).

  23. Changes in plasma osmolality

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of plasma osmolality [mOsm/kg] in capillary blood using the ABL90 FLEX PLUS blood gas analyzer (Radiometer, Denmark).

  24. Changes in dietary energy intake

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of dietary energy intake [kcal] based on 48 hour dietary records analyzed using AvoDiet dietary software (JustForFood sp. z o.o., Poland).

  25. Changes in dietary macronutrient intake

    Time frame: At the Day 0 (familiarization visit), Day 7 (baseline visit), Day 14 (experimental visit 1), and Day 21 (experimental visit 2)

    Assessment of protein, carbohydrate, fat, and dietary fiber intake [g (grams)] based on 48 hour dietary records analyzed using AvoDiet dietary software (JustForFood sp. z o.o., Poland).

Study contacts

Contact information is provided by the study sponsor or research team.

Jakub Adamczewski, MSc

CONTACT

[email protected]

+48 66 317 56 06

Krzysztof Durkalec-Michalski, PhD

CONTACT

[email protected]

+48 61 835 51 65

Sponsors and collaborators

Lead sponsor

Krzysztof Durkalec-Michalski

Other

Registry information

Official study title

Evaluation of the Effect of Acute Sodium Bicarbonate Supplementation on Physical Capacity and Blood Biochemical Marker Concentrations in Highly Trained Female Basketball Players

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jul 28, 2026
Registry last updated
Jul 28, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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