[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-study-detail:100643004":3},{"organization":4,"armGroups":7,"interventions":20,"overallOfficials":26,"centralContacts":31,"locations":39,"responsibleParty":56,"collaborators":26,"id":60,"slug":61,"hasResults":62,"nctId":63,"briefTitle":64,"officialTitle":65,"acronym":26,"eligibilityCriteria":66,"healthyVolunteers":67,"sex":68,"minAge":69,"maxAge":70,"enrollmentInfo":71,"targetDuration":26,"studyType":74,"phases":75,"briefSummary":77,"conditions":78,"keywords":81,"overallStatus":41,"whyStopped":26,"lastUpdateSubmitDate":89,"lastUpdatePostDateStruct":90,"startDateStruct":93,"completionDateStruct":95,"leadSponsor":97,"locationsCount":98},{"fullName":5,"class":6},"The Jerzy Kukuczka Academy of Physical Education in Katowice","OTHER",[8,14],{"label":9,"type":10,"description":11,"interventionNames":12},"Vitamin D3 supplemented group","EXPERIMENTAL","Participants in this arm will receive vitamin D3 supplementation at a total daily dose of 4,000 IU. The supplement will be administered 1 capsule in the evening (with dinner). The intervention period will last for either 4 or 8 weeks.",[13],"Dietary Supplement: Vitamin D supplementation",{"label":15,"type":16,"description":17,"interventionNames":18},"Placebo supplementation group","PLACEBO_COMPARATOR","Participants in this arm will receive placebo supplementation. The supplement will be administered capsule in the evening (with dinner). The intervention period will last for either 4 or 8 weeks.",[19],"Dietary Supplement: Placebo",[21,27],{"type":22,"name":23,"description":24,"armGroupLabels":25,"otherNames":26},"DIETARY_SUPPLEMENT","Vitamin D supplementation","Vitamin D3 will be administered orally in the form of capsules. Participants will ingest a total daily dose of 4,000 IU, split into two doses: 1 capsule (4,000 IU) in the evening with dinner. The intervention will be carried out daily for a duration of either 4 or 8 weeks. Supplementation compliance will be monitored by the research team through capsule counting during follow-up visits.",[9],null,{"type":22,"name":28,"description":29,"armGroupLabels":30,"otherNames":26},"Placebo","An identical placebo will be administered orally in the form of capsule, matching the active vitamin D3 supplement in appearance, size, color, and taste. Participants will ingest 1 placebo capsule in the evening with dinner daily for a duration of either 4 or 8 weeks.",[15],[32,37],{"name":33,"role":34,"phone":35,"phoneExt":26,"email":36},"Małgorzata Michalczyk, Profesor","CONTACT","+48535016532","m.michalczyk@awf.katowice.pl",{"name":33,"role":34,"phone":38,"phoneExt":26,"email":36},"535016532",[40],{"facility":5,"status":41,"city":42,"state":43,"zip":44,"country":45,"countryCode":46,"cosmosGeoPoint":47,"geoPoint":52,"contacts":53},"RECRUITING","Katowice","Mikołowska 72a","40-065","Poland","PL",{"type":48,"coordinates":49},"Point",[50,51],19.02173,50.2597,{"lat":51,"lon":50},[54],{"name":55,"role":34,"phone":38,"phoneExt":26,"email":36},"Małgorzata Michalczyk",{"type":57,"investigatorFullName":58,"investigatorTitle":59,"investigatorAffiliation":5,"oldNameTitle":26,"oldOrganization":26},"PRINCIPAL_INVESTIGATOR","Małgorzata Magdalena Michalczyk","assistant profesor","100643004","effects-of-high-dose-vitamin-d-on-hormones-neuromuscular-function-cognition-and-body-composition-in-athletes-100643004",false,"NCT07641075","Effects of High-Dose Vitamin D on Hormones, Neuromuscular Function, Cognition, and Body Composition in Athletes","The Effect of High-dose Vitamin D Supplementation on Selected Hormone Concentrations, Neuromuscular Transmission, Athletic Performance, Cognitive Functions, and Body Composition in Athletes.","Inclusion Criteria:\n\n* a minimum of 8 years of training experience,\n* absence of injuries in the 6 months leading up to the assessments,\n* consistent engagement in training sessions a minimum of 5 times per week over the last 6 months.\n\nExclusion Criteria:\n\n* vitamin D supplementation within one month prior to the study,\n* use of multivitamin supplements,\n* intestinal disorders.",true,"ALL","17 Years","60 Years",{"count":72,"type":73},200,"ESTIMATED","INTERVENTIONAL",[76],"NA","This study aims to evaluate the effects of high-dose vitamin D3 supplementation on selected physiological, neuromuscular, and cognitive parameters in athletes. At the baseline visit, participants will undergo a series of assessments at the Functional Research Laboratory at AWF Katowice, including a 10 mL venous blood sample collection, body composition analysis (via InBody and DEXA scans), neuromuscular function evaluation using tensiomyography (TMG), and computerized cognitive tests via the Vienna Test System.\n\nFollowing baseline testing, participants will be randomly assigned to either the vitamin D3 group or the placebo group. The active group will receive a daily dose of 4,000 IU of vitamin D3 (1 capsule with dinner), while the control group will receive an identical placebo. The intervention period will last for 4 or 8 weeks. Upon completion of the supplementation period, all baseline assessments will be repeated to evaluate the post-intervention changes.",[79,80],"Vitamin D 25-Hydroxylase Deficiency","Vitamin D Deficiency\u002FInsufficiency",[82,83,84,85,86,87,88],"vitamin D","athletes","coggnitive function","neuro-muscular function","hormones","speed","performance","2026-06-08",{"date":91,"type":92},"2026-06-11","ACTUAL",{"date":94,"type":92},"2025-07-01",{"date":96,"type":73},"2028-12-31",{"name":5,"class":6},1]