What effect does losing weight have on the body of female wrestlers?

The manipulation of body weight can be divided according to the timeline into 3 phases. The first is chronic weight loss (CWL), where fat and muscle mass are reduced by creating an energy deficit. CWL is included a few weeks before a match, depending on the magnitude of the weight reduction. The next phase is acute weight loss (RWL - "rapid weight loss"), when the wrestler needs to fine-tune the body weight and takes place during the wrestling week. Specific strategies are used that target the manipulation of body water and gut contents (low carbohydrate diet, active and passive sweating, etc.). During this phase, dehydration of the body occurs and the reduction in body weight is only temporary. If RWL strategies are used incorrectly, the life of the wrestler may be at risk. Unfortunately, there are known cases where fighters have lost their lives while sweating off the last pounds (Jessica Lindsay - muaythai, Yang Jian Bing - MMA, Billy Jack Saylor - wrestling). The last phase is the replenishment of fluids and nutrients after weigh-ins when rapid weight gain (RWG) occurs as a result. All these phases give us a cycle of weight manipulation.

At the Faculty of Sports Studies at MU, we are conducting specific research looking at the health, nutritional, and exercise-specific determinants in female athletes (more information here). One part of the research will deal with the effect of body weight manipulation on the body of female fighters (muaythai and MMA).

With body weight manipulation, women in the CWL phase are at risk of developing Relative Energy Deficiency Syndrome in Sports (RED-s). Simply put, athletes who have high training energy expenditure and insufficient energy intake are at risk for this syndrome. RED-s has negative effects on the athlete's health and performance parameters. For more information about RED-s syndrome, please refer to the article by Mgr. Kristýna Dvořáková "Relative energy deficiency syndrome in sports in performance athletes in the Czech Republic".

I have already carried out pilot research in my master's studies. It was about the influence of "Pre-match body weight reduction in a muaythai wrestler". In terms of time, this was a shorter-term study (7 weeks) where comprehensive data was collected. I drew inspiration from this data when designing my new research.

The planned research will involve female muaythai and MMA fighters who attend several fights/tournaments throughout the year where they have to reduce their body weight. At the beginning and at the end of the research, they will undergo a comprehensive examination at the Faculty of Sports Studies of MU, where the following parameters will be measured:

• bone densitometry (DEXA) – to determine the values of bone mass and adipose tissue.
• indirect calorimetry – measurement of resting energy metabolism
• critical performance test on a cycle ergometer – to determine performance
• blood ketone bodies

They will also have blood samples taken to determine biochemical markers (hormone levels, vitamins, etc.). In the interim between the baseline and exit measurements (6-8 months), the wrestlers will record their body weight and an evaluation of their nutritional and training record will occur to calculate energy availability.

References:

• REALE, Reid. Acute weight management in combat sports: pre-weight-in weight loss, post-weight-in recovery, and competition nutrition strategies. Sports Science Exchange [online] 2018, Vol.29, No. 183, 1-6. [cited 2022-11-04].
• KASPER, Andreas M., Ben CRIGHTON, Carl LANGAN-EVANS, Philip RILEY, Asheesh SHARMA, Graeme L. CLOSE, and James P. MORTON. Case Study: Extreme Weight Making Causes Relative Energy Deficiency, Dehydration, and Acute Kidney Injury in a Male Mixed Martial Arts Athlete. International Journal of Sports Nutrition [online]. 2019, 29(3), 331-338 [cited 2021-02-05]. DOI: 10.1123/ijsnem.2018-0029. ISSN 1526484X
• MOUNTJOY, Margo, et al. International Olympic Committee (IOC) consensus statement on relative energy deficiency in sport (RED-S): 2018 89 updates. International journal of sport nutrition and exercise metabolism, [online]. 2018, 28.4: 316-331
• LANGAN-EVANS Carl, m. GERMAINE, et al. The physiological and psychological consequences of low energy availability in a male combat sports athlete. Medicine and science in sport and exercise [online] 2020, 8 September DOI: 10.1249/MSS.0000000000002519