The Effects of Vitamin D Supplements on Sports Performance of Female Indoor Elite Athletes

NCT07748650 | Completed

• 1 other identifier: FJUH110099
• Study Type: interventional
• Target: 37
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Female Indoor Athletes

Keywords

female athletes; calcium; vitamin D; sports performance

Outcome Measures

Primary Outcomes (4)

• 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

  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.

  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.

  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.

  From the entrollment to post-test at 90 days.

Study Arms (3)

Vitamin D group

EXPERIMENTAL

Participants received daily vitamin D of 5000 IU (125 μg) throughout the intervention period.

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.

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.

Drug: Placebo

Interventions

Cholecalciferol (Vit D3) DRUG

Participants received 12 oral drops of vitamin D3 (cholecalciferol), providing a total daily dose of 5,000 IU (125 μg).

Vitamin D group

Calcium & Vitamine D3 DRUG

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.

Vitamin D and Calcium group

Placebo DRUG

Participants received a placebo which does not contain vitamin D (contains medium-chain fatty acid oil), and a calcium placebo.

Control Group

Eligibility Criteria

• Age: 20 Years+
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Athletes in Taiwan's top corporate league or semi-professional league that has been training and competing indoors for a long time.

You may not qualify if:

• 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

Sponsors & Collaborators

• Fu Jen Catholic University Hospital: lead

Study Sites (1)

Fu Jen Catholic University Hospital

New Taipei City, Taiwan

Location

Related Publications (5)

• 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.

  PMID: 28577257 BACKGROUND

• Holick 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.

  PMID: 22442274 BACKGROUND

• Zhang 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.

  PMID: 21143872 BACKGROUND

• Morton 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.

  PMID: 22554144 BACKGROUND

• Maestro 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.

  PMID: 12711007 BACKGROUND

MeSH Terms

Interventions

Cholecalciferol; Calcium

Intervention Hierarchy (Ancestors)

Cholestenes; Cholestanes; Steroids; Fused-Ring Compounds; Polycyclic Compounds; Sterols; Vitamin D; Secosteroids; Membrane Lipids; Lipids; Metals, Alkaline Earth; Elements; Inorganic Chemicals; Metals; Blood Coagulation Factors; Biological Factors

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Chief Principal Investigator

Model Details: Vitamin D group, Vitamin D + Calcium group, and Control (Placebo) group

Study Record Dates

• First Submitted: July 22, 2026
• First Posted: August 6, 2026
• Study Start: July 22, 2021
• Primary Completion: July 22, 2022
• Study Completion: December 31, 2022
• Last Updated: August 6, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

TW (1)