Hormonal contraceptive use and physical performance, body composition, and musculoskeletal injuries during military training

O'Leary, Thomas J., Evans, Hope A., Close, Marie-Elise O., Izard, Rachel M., Walsh, Neil P., Coombs, Charlotte V., Carswell, Alexander T., Oliver, Samuel J., Tang, Jonathan C. Y. ORCID: https://orcid.org/0000-0001-6305-6333, Fraser, William D. and Greeves, Julie P. (2024) Hormonal contraceptive use and physical performance, body composition, and musculoskeletal injuries during military training. Medicine and Science in Sports and 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:	Data Availability Statement: All data and code are available from the corresponding author pending approval of public release from UK Ministry of Defence. Funding information: This study was funded by the UK Ministry of Defence (Army).
Faculty \ School:	Faculty of Medicine and Health Sciences > Norwich Medical School
UEA Research Groups:	Faculty of Medicine and Health Sciences > Research Centres > Lifespan Health Faculty of Medicine and Health Sciences > Research Groups > Musculoskeletal Medicine Faculty of Medicine and Health Sciences > Research Centres > Metabolic Health
Depositing User:	LivePure Connector
Date Deposited:	16 Oct 2024 09:30
Last Modified:	17 Nov 2024 07:30
URI:	https://ueaeprints.uea.ac.uk/id/eprint/97036
DOI:	10.1249/MSS.0000000000003588

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