There is a lack of research documenting the weight-making practices of mixed-martial-arts (MMA) competitors. The purpose of the investigation was to quantify the magnitude and identify the methods of rapid weight loss (RWL) and rapid weight gain (RWG) in MMA athletes preparing for competition. Seven athletes (mean ± SD, age 24.6 ± 3.5 yrs, body mass 69.9 ± 5.7 kg, competitive experience 3.1 ± 2.2 yrs) participated in a repeated-measures design. Measures of dietary intake, urinary hydration status, and body mass were recorded in the week preceding competition. Body mass decreased significantly (p < .0005) from baseline by 5.6 ± 1.4 kg (8 ± 1.8%). During the RWG period (32 ± 1 hr) body mass increased significantly (p < .001) by 7.4 ± 2.8 kg (11.7 ± 4.7%), exceeding RWL. Mean energy and carbohydrate intake were 3176 ± 482 kcal・day and 471 ± 124 g・day, respectively. At the official weigh-in 57% of athletes were dehydrated (1033 ± 19 mOsmol・kg) and the remaining 43% were severely dehydrated (1267 ± 47 mOsmol・kg). Athletes reported using harmful dehydration-based RWL strategies, including sauna (43%) and training in plastic suits (43%). Results demonstrated RWG greater than RWL, this is a novel finding and may be attributable to the 32 hr duration from weigh-in till competition. The observed magnitude of RWL and strategies used are comparable to those which have previously resulted in fatalities. Rule changes which make RWL impractical should be implemented with immediate effect to ensure the health, safety and wellbeing of competitors.

Weight-category sports are defined by the requirement of a weigh-in before competition to provide performance equity and reduced injury risks by eliminating size discrepancies. Athletes in these sports try to gain a theoretical advantage by competing in weight divisions that are lower than their day-to-day body mass (BM), using a combination of chronic strategies (body-fat losses) and acute manipulations over a period of hours to days before weigh-in (“making weight”). Strategies to support safer practices include minimal competition weight classification based on preseason body composition, reductions in the period between weigh-in and competition, and prohibition of unhealthy weight loss techniques. At an individual level, expert guidance by a sports nutrition professional can help an athlete to establish a pragmatic and long-term approach to BM management, recognizing the nuances of their sport, to achieve favorable outcomes for both health and performance.

1 2 Combat sport athletes typically engage in a process called making-3 weight, characterised by rapid weight loss (RWL) and subsequent 4 rapid weight gain (RWG) in the days preceding competition. These 5 practices differ across each sport, but no systematic comparison of the 6 size of the changes in body mass exists. The aim was to determine the 7 magnitude of RWL and RWG in combat sport athletes preparing for 8 competition. The review protocol was preregistered with PROSPERO 9 [CRD42017055279]. In eligible studies, athletes prepared habitually 10 with a RWL period ≤7 days preceding competition. An electronic 11 search of EBSCOhost (CINAHL Plus, MEDLINE, SPORTDiscus) 12 and PubMed Central was performed to July 2018. Sixteen full-text 13 studies (total 4432 participants, 156 female, 4276 male) were included, 14 providing data from five combat sports (boxing, judo, mixed martial 15 arts (MMA), taekwondo and wrestling). Three studies reported RWL 16 and fourteen studies reported RWG. Duration permitted for RWG 17 ranged 3-32 hours. The largest changes in body mass occurred in two 18 separate MMA cohorts (RWL 7.4 ± 1.1kg [~10%], RWG 7.4 ± 2.8kg 19[11.7 ± 4.7%]). The magnitude of RWG appears to be influenced by 20 the type of sport, competition structure, and recovery duration 21 permitted. A cause for concern is the lack of objective data quantifying 22 the magnitude of RWL. There is insufficient evidence to substantiate 23 the use of RWG as a proxy for RWL, and little data are available in 24 females. By engaging in RWG, athletes are able to exploit rules to 25 compete up to three weight categories higher than at the official weigh-26 in. 27 28 2 2

No funding was received for writing this manuscript. GGA has been supported financially by Fundação de Amparo à Pesquisa do Estado de São Paulo (FASESP; grant number: 2014/11948-8). MDT has received a British Council award to support a studentship focused on research into carnosine (grant number: 209524711). JJM, GGA, and MDT collectively declare that they have no competing interests. CS has received β-alanine supplements free of charge from Natural Alternatives International (NAI) for use in experimental investigations; NAI have also supported open access page charges for some manuscripts. The review is presented honestly, and without fabrication, falsification, or inappropriate data manipulation. The viewpoints expressed in the review do not constitute endorsement by the American College of Sports Medicine.