Author Identifier

Colin Doherty: http://orcid.org/0000-0002-3589-7490

Date of Award

2025

Document Type

Thesis

Publisher

Edith Cowan University

Degree Name

Doctor of Philosophy

School

School of Medical and Health Sciences

First Supervisor

Oliver Barley

Second Supervisor

Lauren Fortington

Abstract

Background: Athletes in mixed martial arts (MMA) and Muay Thai (MT) face challenges before, 3 during, and after competition, including hydration testing, disordered eating (DE), rapid weight changes 4 (RWC), and health problems (HP). These issues can affect athletes' health and performance and raise 5 regulatory and safety concerns for governing bodies like the Western Australia Combat Sports 6 Commission (WACSC). However, these challenges are poorly described in the context of MMA and 7 MT, as most of the existing research focuses on Olympic combat sports. This thesis addresses these 8 challenges in MMA and MT, aiming to identify areas where the WACSC can improve athlete health 9 and safety. Structured as a thesis by publication, it consists of seven manuscripts that provide insights 10 into the accuracy and reliability of hydration testing, prevalence of DE, relationship between RWC and 11 competitive success, competition-related HPs, relationship between RWC and injury, and injury-related 12 HPs reported by athletes and medical practitioners. Methods: Both laboratory and survey research were 13 conducted. The laboratory study recruited 30 combat sports athletes (15 male and 15 female) who 14 underwent a sauna protocol (six 30-minute sessions) on two separate occasions. To investigate whether 15 sauna-induced body mass loss (BML) could explain changes in hydration biomarkers, the test-retest 16 reliability of blood, urine, and tear biomarkers was examined, along with potential sex-specific 17 differences. The survey research analysed data from 24 to 26 combat sports events over a 12- to 14-18 month surveillance period. Athletes responded to online questionnaires at different time points, with 19 DE and HP questionnaires completed 7 days post-competition and RWC questionnaire completed 1 day 20 post-competition. Official fight data, weigh-in body mass (BM), secondary weigh-in BM, and medical 21 practitioner-reported injuries were provided by the WACSC. Results: The laboratory study found that 22 BML accounted for less than 25% of the variation in hydration biomarkers, with biomarkers displaying 23 poor to moderate test-retest reliability. Changes in blood biomarkers also varied by sex. Survey results 24 indicated that two out of five athletes reported at least one competition HP. Among female athletes, 25 greater rapid weight loss in the 24 hours before weigh-ins (RWL –24 hours) was associated with 26 winning (OR: 1.57, p = 0.001). In males, RWL –24 hours was associated with injury-related HPs (OR: 27 1.20, p = 0.044). Additionally, 83% of males and 89% of females scored moderate to very high for DE. 28 Discrepancies were observed between athlete-reported and medical practitioner-recorded injuries: 97 29 athletes reported injury-related HPs, but only 25 were confirmed by physicians, with documentation 30 lacking for 82 cases. Conclusion: Current hydration biomarkers are both inaccurate and unreliable, 31 rendering them unsuitable for managing weight-cutting practices in combat sports. Approximately two 32 out of five combat sports athletes report experiencing HPs post-competition, with RWC associated with 33 both competitive success and increased injury risk. Additionally, most combat athletes grapple with 34 DE, highlighting these issues as crucial areas for intervention. These findings underscore the need for 35 educating athletes on safe RWC practices and providing support for those facing DE concerns to 36 promote career longevity, reduce injury risk, and improve weight management in MMA and MT.

DOI

10.25958/rcc6-gm46

Access Note

Access to this thesis is embargoed until 5th July 2026

Available for download on Sunday, July 05, 2026

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