Hormonal Contraceptive Use and Physical Performance, Body Composition, and Musculoskeletal Injuries during Military Training

O'Leary, TJ, Evans, HA, Close, MEO, Izard, RM, Walsh, NP ORCID: 0000-0002-3681-6015, Coombs, CV, Carswell, AT, Oliver, SJ, Tang, JCY, Fraser, WD and Greeves, JP (2024) Hormonal Contraceptive Use and Physical Performance, Body Composition, and Musculoskeletal Injuries during Military Training. Medicine & Science in Sports & Exercise. ISSN 0195-9131

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Abstract

Purpose: To investigate associations between hormonal contraceptive use and physical performance, body composition, and musculoskeletal injuries in basic military training. Methods: Female British Army recruits (n = 450) were grouped as non-users (n = 182), combined oral contraceptive users (COCP; n = 184), or progestin-only users (POC; n = 144). Physical performance (2.4 km run, lift strength, leg power), body composition, iron and vitamin D status, and bone metabolism were measured at the start (week 1) and end (week 13) of training. Lower body musculoskeletal injuries were recorded from medical records. Results: Training decreased 2.4 km run time (-3.7%) and fat mass (-9.6%), and increased lift strength (4.5%), leg power (1.5%), lean mass (5.4%), and whole-body (0.9%), arms (1.8%), and legs (1.4%) aBMD (p ≤ 0.015); the training response was not different between groups (p ≥ 0.173). Lift strength was lower in COCP users than non-users (p = 0.044). Whole-body, trunk, and legs aBMD were lower in POC users than non-users and/or COCP users (p ≤ 0.041). There were no associations between hormonal contraceptive use and musculoskeletal or bone stress injury (p ≥ 0.429). Training did not change ferritin (p = 0.968), but decreased haemoglobin and total 25(OH)D, and increased PTH, βCTX, and PINP (p ≤ 0.005); the training response was not different between groups (p ≥ 0.368). Total 25(OH)D was higher, and βCTX and PINP were lower, in COCP users than non-users and POC users; PTH was lower in COCP users than non-users, and; βCTX and PINP were higher in POC users than non-users (p ≤ 0.017). Conclusions: Hormonal contraceptive use was not associated with performance or injury outcomes in military training.

Item Type:	Article
Additional Information:	This is a pre-copyedited, author-produced version of an article accepted for publication in Medicine & Science in Sports & Exercise. The published version of record O’Leary, Thomas J.1,2; Evans, Hope A.1; Close, Marie-Elise O.1; Izard, Rachel M.3; Walsh, Neil P.4; Coombs, Charlotte V.1; Carswell, Alexander T.5; Oliver, Samuel J.6; Tang, Jonathan C. Y.5,7; Fraser, William D.5,7; Greeves, Julie P.1,2,5. Hormonal Contraceptive Use and Physical Performance, Body Composition, and Musculoskeletal Injuries during Military Training. Medicine & Science in Sports & Exercise ():10.1249/MSS.0000000000003588, November 6, 2024. | DOI: 10.1249/MSS.0000000000003588 is available online at: https://doi.org/10.1249/mss.0000000000003588
Uncontrolled Keywords:	Prevention; Physical Injury - Accidents and Adverse Effects; 1106 Human Movement and Sports Sciences; 1116 Medical Physiology; 1117 Public Health and Health Services; Sport Sciences
Subjects:	R Medicine > RC Internal medicine > RC1200 Sports Medicine U Military Science > U Military Science (General)
Divisions:	Sport and Exercise Sciences
Publisher:	Lippincott, Williams & Wilkins
Date of acceptance:	11 October 2024
Date Deposited:	14 Jan 2025 10:45
Last Modified:	03 Jul 2025 16:30
DOI or ID number:	10.1249/MSS.0000000000003588
URI:	https://researchonline.ljmu.ac.uk/id/eprint/25260

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