Female Indoor AthletesRCTNCT07748650
The Effects of Vitamin D Supplements on Sports Performance of Female Indoor Elite Athletes
A study testing Cholecalciferol (Vit D3) and Calcium & Vitamine D3 in people with Female Indoor Athletes, run by Fu Jen Catholic University Hospital at 1 site in Taiwan.
Trial summary
This study is a randomized, double-blind study evaluated the effects of 90 days of vitamin D supplementation, with or without calcium, on bone mineral density and sports performance in indoor female semiprofessional athletes. Read more about this study
- Who is it for?
- Ages 20 years and older, women onlyHealthy volunteers can take part
- Conditions the study is for
- Female Indoor Athletes
- What is being tested?
- Cholecalciferol (Vit D3) and Calcium & Vitamine D3
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 37 participants
- Where
- 1 siteTaiwan
- Study dates
- 22 Jul 2021to 31 Dec 2022
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 20 years and older
- Women only
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Athletes in Taiwan's top corporate league or semi-professional league that has been training and competing indoors for a long time.
Who cannot join
- Under 20 years old
- Pregnant
- Being in vulnerable groups such as prisoners or mentally handicapped, disabled, etc.
- Had skeletal muscle-related injuries or surgeris
- Have kidney and/or liver disease, lipid malabsorption of calcium and vitamin
- Having organ stones
- Have taken supplments and/or calcium and/or vitamin D and/or other related health foods within two weeks
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Effects of Vitamin D Supplements on Sports Performance of Female Indoor Elite Athletes: a Randomized Double-blind Controlled Study
This study is a randomized, double-blind study evaluated the effects of 90 days of vitamin D supplementation, with or without calcium, on bone mineral density and sports performance in indoor female semiprofessional athletes.
Read the detailed description
Vitamin D and calcium are essential for bone health, with vitamin D also influencing muscle function, immunity, and inflammation. The primary source of vitamin D is skin synthesis via UVB exposure, though deficiency is common, especially in indoor athletes. There are current mixed evidences on whether vitamin D supplementation improves sports performance, despite its role in muscle physiology and bone health. Female triad athletes are particularly vulnerable due to risks of low energy availability, bone loss, and menstrual irregularities. Therefore, the purpose of this study is to investigate the effects of vitamin D and calcium supplementation on bone mineral density and performance in female athletes. A randomized, double-blinded study was conducted, including a total of 37 young female semiprofessional athletes. The participants were divided into three groups of one) vitamin D supplements (5000 IU, 125 μg/day), two) vitamin D (5000 IU, 125 μg/day) and calcium supplement (600 mg/day), and three) control group (medium-chain triglycerides) intervention for 90 days. Blood draws, bone density test, and other values were used to assess the changes in the bone and nutritional status. Subjective and objective values were used to evaluate the sports performance.
- Conditions
- Female Indoor Athletes
- Being tested
- Cholecalciferol (Vit D3), Calcium & Vitamine D3, Placebo
- Keywords
- female athletes, calcium, vitamin D, sports performance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Cholecalciferol (Vit D3)Drug
Participants received 12 oral drops of vitamin D3 (cholecalciferol), providing a total daily dose of 5,000 IU (125 μg).
Calcium & Vitamine D3Drug
Participants received 12 oral drops of vitamin D3 (cholecalciferol), providing a total daily dose of 5,000 IU (125 μg), together with one 600 mg calcium tablet taken orally once daily.
PlaceboDrug
Participants received a placebo which does not contain vitamin D (contains medium-chain fatty acid oil), and a calcium placebo.
| Study group | Role | What they receive |
|---|---|---|
| Vitamin D group | Experimental | Participants received daily vitamin D of 5000 IU (125 μg) throughout the intervention period. Receives: Drug: Cholecalciferol (Vit D3) |
| Vitamin D and Calcium group | Active comparator | Participants received one calcium tablet (600mg) daily and daily vitamin D of 5000 IU (125 μg) throughout the intervention period. Receives: Drug: Calcium & Vitamine D3 |
| Control Group | Placebo comparator | Participants received a placebo which does not contain vitamin D (contains medium-chain fatty acid oil), and a calcium placebo throughout the intervention period. Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
isokinetic muscle strength Biodex
Using the Biodex System 4 QuickSet, the players performed the maximum extension and flexion muscle strength test of the knee joints at 60∘ per second and 180∘ per second angular velocities. The action range is from 90∘ to 0∘. The maximum eccentric contraction was repeated five times, and the sequence was from slow to high angular velocity
Measured: From enrollment to the end post-test at 90 days.
Star excursion balance test
The players stood in the center of the star with bare feet. With their hands placed firmly on their hips, the left foot stood at the center point to control their balance while the right foot was used as a reaching foot, directing their positions onto another point. They must extend the right foot as far as possible in a straight line, lightly touch with their toes at the farthest distance, and then return to the center point and rest for two to five seconds. They have to repeat this step eight times in a clockwise direction, and then repeat this same test by changing the sides of their foot counterclockwise direction in a sequence. Finally, the testers recorded the length of each direction (with a minimum unit of 0.5 cm), and recorded the best distance for subsequent analysis. This test was done three times.
The scale is reach distance (CM). Minimum is 0CM, and there is no fixed macimum. If greater reach distance is achieved, that means better dynamic balance.
Measured: From enrollment to the end post-test at 90 days.
Vertical jump test
The players hold a piece of tape, standing on the sideway of the wall. They then have to squat down, swing their arms, and jump up vertically as high as possible, extending their legs and arms.
The scale is jump height in cm. Minimum score is 0cm, and there is no fixed maximum. If higher jump is reached, that means they have a better lower-limb power.
Measured: From enrollment to the end post-test at 90 days.
T-shape agility test
The players ran back and forth on four T-shaped angular cones. They 17performed a total of three tests and were recorded for the best speed for the subsequent analysis. Lastly, on the sport performance test, a 20-meter sprint test was recorded. The players started to sprint when instructed from a static position on a basketball court. Players performed three times with the best time recorded for subsequent analysis. The scale is measured in times (sec), minimum is 0 sec and there is no fixed maximum. When lower time is achieved, that means they have better agility.
Measured: From the entrollment to post-test at 90 days.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Aug 2026
- Study start22 Jul 2021
- Primary completion22 Jul 2022
- Study completion31 Dec 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for Female Indoor AthletesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Vitamin D group, Vitamin D + Calcium group, and Control (Placebo) group
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 37 participants (actual)
Sponsor and investigators
- Lead sponsor
- Fu Jen Catholic University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Chia-Hung Hung, Fu Jen Catholic University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07748650
- Sponsor's protocol ID
- FJUH110099
- Acronym
- RCT
- Status last verified
- Jul 2026
- First submitted
- 22 Jul 2026
- Last updated
- 6 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared because the informed consent obtained from participants and the study's ethics approval did not include provisions for sharing de-identified participant-level data outside the research team.
Publications
Farrokhyar F, Sivakumar G, Savage K, Koziarz A, Jamshidi S, Ayeni OR, Peterson D, Bhandari M. Effects of Vitamin D Supplementation on Serum 25-Hydroxyvitamin D Concentrations and Physical Performance in Athletes: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Sports Med. 2017 Nov;47(11):2323-2339. doi: 10.1007/s40279-017-0749-4.
PubMed 28577257Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM. Guidelines for preventing and treating vitamin D deficiency and insufficiency revisited. J Clin Endocrinol Metab. 2012 Apr;97(4):1153-8. doi: 10.1210/jc.2011-2601. Epub 2012 Mar 22. No abstract available.
PubMed 22442274Zhang R, Naughton DP. Vitamin D in health and disease: current perspectives. Nutr J. 2010 Dec 8;9:65. doi: 10.1186/1475-2891-9-65.
PubMed 21143872Morton JP, Iqbal Z, Drust B, Burgess D, Close GL, Brukner PD. Seasonal variation in vitamin D status in professional soccer players of the English Premier League. Appl Physiol Nutr Metab. 2012 Aug;37(4):798-802. doi: 10.1139/h2012-037. Epub 2012 May 4.
PubMed 22554144Maestro B, Davila N, Carranza MC, Calle C. Identification of a Vitamin D response element in the human insulin receptor gene promoter. J Steroid Biochem Mol Biol. 2003 Feb;84(2-3):223-30. doi: 10.1016/s0960-0760(03)00032-3.
PubMed 12711007
Study at a glance
From the registry record, last updated by the sponsor on 6 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effects of Vitamin D Supplements on Sports Performance of Female Indoor Elite Athletes: a Randomized Double-blind Controlled Study
- ClinicalTrials.gov ID
- NCT07748650
- Acronym / sponsor ID
- RCT / FJUH110099
- Conditions
- Female Indoor Athletes
- Keywords
- female athletes, calcium, vitamin D, sports performance
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 37 participants (actual)
- Lead sponsor
- Fu Jen Catholic University HospitalUniversity, hospital or other
- Study start
- 22 Jul 2021 (actual)
- Primary completion
- 22 Jul 2022 (actual)
- Study completion
- 31 Dec 2022 (actual)
- First posted
- 6 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is a randomized, double-blind study evaluated the effects of 90 days of vitamin D supplementation, with or without calcium, on bone mineral density and sports performance in indoor female semiprofessional athletes.
Detailed description
Vitamin D and calcium are essential for bone health, with vitamin D also influencing muscle function, immunity, and inflammation. The primary source of vitamin D is skin synthesis via UVB exposure, though deficiency is common, especially in indoor athletes. There are current mixed evidences on whether vitamin D supplementation improves sports performance, despite its role in muscle physiology and bone health. Female triad athletes are particularly vulnerable due to risks of low energy availability, bone loss, and menstrual irregularities. Therefore, the purpose of this study is to investigate the effects of vitamin D and calcium supplementation on bone mineral density and performance in female athletes. A randomized, double-blinded study was conducted, including a total of 37 young female semiprofessional athletes. The participants were divided into three groups of one) vitamin D supplements (5000 IU, 125 μg/day), two) vitamin D (5000 IU, 125 μg/day) and calcium supplement (600 mg/day), and three) control group (medium-chain triglycerides) intervention for 90 days. Blood draws, bone density test, and other values were used to assess the changes in the bone and nutritional status. Subjective and objective values were used to evaluate the sports performance.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
- Model description
- Vitamin D group, Vitamin D + Calcium group, and Control (Placebo) group
| Arm | Type | Receives |
|---|---|---|
| Vitamin D group | Experimental | Drug: Cholecalciferol (Vit D3)Participants received daily vitamin D of 5000 IU (125 μg) throughout the intervention period. |
| Vitamin D and Calcium group | Active comparator | Drug: Calcium & Vitamine D3Participants received one calcium tablet (600mg) daily and daily vitamin D of 5000 IU (125 μg) throughout the intervention period. |
| Control Group | Placebo comparator | Drug: PlaceboParticipants received a placebo which does not contain vitamin D (contains medium-chain fatty acid oil), and a calcium placebo throughout the intervention period. |
Who may qualify
- Ages
- 20 years and older
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Athletes in Taiwan's top corporate league or semi-professional league that has been training and competing indoors for a long time.
Key exclusion criteria (7 listed)
- Under 20 years old
- Pregnant
- Being in vulnerable groups such as prisoners or mentally handicapped, disabled, etc.
- Had skeletal muscle-related injuries or surgeris
- Have kidney and/or liver disease, lipid malabsorption of calcium and vitamin
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Cholecalciferol (Vit D3)Participants received 12 oral drops of vitamin D3 (cholecalciferol), providing a total daily dose of 5,000 IU (125 μg). | Drug | Vitamin D group |
| Calcium & Vitamine D3Participants received 12 oral drops of vitamin D3 (cholecalciferol), providing a total daily dose of 5,000 IU (125 μg), together with one 600 mg calcium tablet taken orally once daily. | Drug | Vitamin D and Calcium group |
| PlaceboParticipants received a placebo which does not contain vitamin D (contains medium-chain fatty acid oil), and a calcium placebo. | Drug | Control Group |
Primary outcome
isokinetic muscle strength Biodex
Time frame: From enrollment to the end post-test at 90 days.
Using the Biodex System 4 QuickSet, the players performed the maximum extension and flexion muscle strength test of the knee joints at 60∘ per second and 180∘ per second angular velocities. The action range is from 90∘ to 0∘. The maximum eccentric contraction was repeated five times, and the sequence was from slow to high angular velocity
Star excursion balance test
Time frame: From enrollment to the end post-test at 90 days.
The players stood in the center of the star with bare feet. With their hands placed firmly on their hips, the left foot stood at the center point to control their balance while the right foot was used as a reaching foot, directing their positions onto another point. They must extend the right foot as far as possible in a straight line, lightly touch with their toes at the farthest distance, and then return to the center point and rest for two to five seconds. They have to repeat this step eight times in a clockwise direction, and then repeat this same test by changing the sides of their foot counterclockwise direction in a sequence. Finally, the testers recorded the length of each direction (with a minimum unit of 0.5 cm), and recorded the best distance for subsequent analysis. This test was done three times. The scale is reach distance (CM). Minimum is 0CM, and there is no fixed macimum. If greater reach distance is achieved, that means better dynamic balance.
Vertical jump test
Time frame: From enrollment to the end post-test at 90 days.
The players hold a piece of tape, standing on the sideway of the wall. They then have to squat down, swing their arms, and jump up vertically as high as possible, extending their legs and arms. The scale is jump height in cm. Minimum score is 0cm, and there is no fixed maximum. If higher jump is reached, that means they have a better lower-limb power.
T-shape agility test
Time frame: From the entrollment to post-test at 90 days.
The players ran back and forth on four T-shaped angular cones. They 17performed a total of three tests and were recorded for the best speed for the subsequent analysis. Lastly, on the sport performance test, a 20-meter sprint test was recorded. The players started to sprint when instructed from a static position on a basketball court. Players performed three times with the best time recorded for subsequent analysis. The scale is measured in times (sec), minimum is 0 sec and there is no fixed maximum. When lower time is achieved, that means they have better agility.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Aug 2026.
- Background: PubMed 28577257Farrokhyar F, Sivakumar G, Savage K, Koziarz A, Jamshidi S, Ayeni OR, Peterson D, Bhandari M. Effects of Vitamin D Supplementation on Serum 25-Hydroxyvitamin D Concentrations and Physical Performance in Athletes: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Sports Med. 2017 Nov;47(11):2323-2339. doi: 10.1007/s40279-017-0749-4.
- Background: PubMed 22442274Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, Hanley DA, Heaney RP, Murad MH, Weaver CM. Guidelines for preventing and treating vitamin D deficiency and insufficiency revisited. J Clin Endocrinol Metab. 2012 Apr;97(4):1153-8. doi: 10.1210/jc.2011-2601. Epub 2012 Mar 22. No abstract available.
- Background: PubMed 21143872Zhang R, Naughton DP. Vitamin D in health and disease: current perspectives. Nutr J. 2010 Dec 8;9:65. doi: 10.1186/1475-2891-9-65.
- Background: PubMed 22554144Morton JP, Iqbal Z, Drust B, Burgess D, Close GL, Brukner PD. Seasonal variation in vitamin D status in professional soccer players of the English Premier League. Appl Physiol Nutr Metab. 2012 Aug;37(4):798-802. doi: 10.1139/h2012-037. Epub 2012 May 4.
- Background: PubMed 12711007Maestro B, Davila N, Carranza MC, Calle C. Identification of a Vitamin D response element in the human insulin receptor gene promoter. J Steroid Biochem Mol Biol. 2003 Feb;84(2-3):223-30. doi: 10.1016/s0960-0760(03)00032-3.
- Individual participant dataSharing planned: No. Individual participant data will not be shared because the informed consent obtained from participants and the study's ethics approval did not include provisions for sharing de-identified participant-level data outside the research team.
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Cholecalciferol (Vit D3) and Calcium & Vitamine D3 in people with Female Indoor Athletes, run by Fu Jen Catholic University Hospital at 1 site in Taiwan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Taiwan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
isokinetic muscle strength Biodex (time frame: From enrollment to the end post-test at 90 days.). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07748650, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Aug 2026.