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Dehydration and Acute Weight Gain in Mixed Martial Arts Fighters Before Competition

Jetton, Adam M.1; Lawrence, Marcus M.1; Meucci, Marco2; Haines, Tracie L.1; Collier, Scott R.1; Morris, David M.1; Utter, Alan C.1

Journal of Strength and Conditioning Research: May 2013 - Volume 27 - Issue 5 - p 1322–1326
doi: 10.1519/JSC.0b013e31828a1e91
Original Research

Jetton, AM, Lawrence, MM, Meucci, M, Haines, TL, Collier, SR, Morris, DM, and Utter, AC. Dehydration and acute weight gain in mixed martial arts fighters before competition. J Strength Cond Res 27(5): 1322–1326, 2013—The purpose of this study was to characterize the magnitude of acute weight gain (AWG) and dehydration in mixed martial arts (MMA) fighters before competition. Urinary measures of hydration status and body mass were determined approximately 24 hours before and then again approximately 2 hours before competition in 40 MMA fighters (mean ± SE, age: 25.2 ± 0.65 years, height: 1.77 ± 0.01 m, body mass: 75.8 ± 1.5 kg). The AWG was defined as the amount of body weight the fighters gained in the approximately 22-hour period between the official weigh-in and the actual competition. On average, the MMA fighters gained 3.40 ± 2.2 kg or 4.4% of their body weight in the approximately 22-hour period before competition. Urine specific gravity significantly decreased (p < 0.001) from 1.028 ± 0.001 to 1.020 ± 0.001 during the approximately 22-hour rehydration period. Results demonstrated that 39% of the MMA fighters presented with a Usg of >1.021 immediately before competition indicating significant or serious dehydration. The MMA fighters undergo significant dehydration and fluctuations in body mass (4.4% avg.) in the 24-hour period before competition. Urinary measures of hydration status indicate that a significant proportion of MMA fighters are not successfully rehydrating before competition and subsequently are competing in a dehydrated state. Weight management guidelines to prevent acute dehydration in MMA fighters are warranted to prevent unnecessary adverse health events secondary to dehydration.

1Department of Health, Leisure, and Exercise Science; Appalachian State University, Boone, North Carolina; and

2Department of Health Sciences, University of Rome “Foro Italico,” Rome, Italy

Address correspondence to Alan C. Utter,

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Mixed Martial Arts (MMA) is a complex combat sport that integrates many fighting styles including boxing, wrestling, judo, muay thai, and Brazilian jiu-jitsu as its main components. All athletes in MMA are required to attain a specific body weight (weight class) before competing in a regulated bout. The purpose for weight classes is to match athletes that are of a similar size to create an equal playing level and minimize the risk of injury between opponents. Similar to MMA, the sport of wrestling also incorporates weight classes for competition. Previous studies with wrestlers have demonstrated that mandating weight classes can lead to subsequent participation in acute rapid body water loss and dehydration just before official weigh-ins (8,11,14) by means of excessive exercise, sweat suits, and extreme environments. The strategy of acute rapid weight loss is used with hopes of gaining a competitive advantage of strength and power over an opponent who does not reduce body weight to meet the same weight class.

Acute rapid weight loss can lead to extreme dehydration. Dehydration or excess body water loss has negative physiological consequences that impair performance and also can be hazardous to one's health. These adverse effects include impaired glycogen use, central nervous system dysfunction, increases in core temperature and cardiovascular strain (9). In the year 1997, water loss levels ranging from 6.7 to 10% body weight contributed to heat-related deaths in 3 collegiate wrestlers (8). The deaths of these 3 wrestlers resulted in significant public attention to the unsafe rapid weight loss measures, which ultimately led to regulation rule changes in collegiate wrestling including: manipulation of weight classes, week-to-week weight loss limits, body composition assessment, validation of minimal competitive weight class through body composition assessment, and prohibiting extreme rapid weight loss methods (10). The new regulations were later investigated for their effectiveness and were reported to be successful by minimizing unhealthy weight loss of collegiate wrestlers (17).

During competitive MMA events, the official weigh-in is typically held 10–24 hours before competition for both the amateur and professional athletes. This is similar to the time period between the official weigh-in and competition of amateur wrestling before the deaths of the 3 collegiate wrestlers in 1997 (17). In the USA, current regulations now require high-school (HS) and collegiate aged wrestlers to weigh-in 1–2 hours before competition depending on the event. The time period between the official weigh-in and competition is when athletes attempt to rehydrate and regain as much body weight back as possible. Aside from the time period between weigh-in and competition other differences between MMA and wrestling include a smaller number of weight classes, which results in a greater weight interval between them, which may lead athletes to adopt more severe weight loss behaviors. Other differences include number of competition per year; length of the competitive season; and scheduling, organization, and compensation for competition all of which will drive weight loss behaviors. Consequently, findings from previous studies conducted on wrestlers cannot be exclusively extended to MMA athletes. Unlike HS and collegiate wrestling, there are currently no guidelines or rules to minimize rapid weight loss and subsequent adverse health events in the sport of MMA fighting.

Given the popularity of MMA around the word, the number of athletes at risk of health-related injuries because of rapid weight loss has become a growing concern among the sports medicine profession. If MMA athletes are engaging in significant rapid weight loss before competition, coupled with a time period that may be insufficient for complete rehydration, MMA competitors could be increasing their likelihood of an untoward health event both before and during competition. To our knowledge, this is the first study to evaluate the magnitude of rapid weight gain and changes in hydration status in MMA fighters before competition. Therefore, the purpose of the present investigation was to quantify the extent of dehydration, acute weight gain (AWG; defined as the amount of weight gained between the official weigh-in and competition), and rehydration in MMA fighters before competition. It is hoped that results of this investigation will provide the impetus for body weight management guidelines for MMA fighters that promote safe participation and prevent unhealthy weight loss behaviors.

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Experimental Approach to the Problem

The specific aim of this study was to evaluate the magnitude of AWG and dehydration in MMA fighters before competition in an actual competitive environment. Urinary measures of hydration status and body mass were determined approximately 24 hours before and then again approximately 2 hours before competition in 40 competitive MMA fighters. The research experiment was descriptive in nature and followed a repeated-measures design in which each subject served as his or her own control.

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Forty male (N = 38) and female (N = 2) MMA fighters participated in this study. All the fighters were required to pass a prefight physical to be eligible for this investigation. Data were collected during 2 separate MMA events in the states of North and South Carolina. Written, voluntary, informed consent was obtained from each subject before all testing, and all the procedures were approved by the Appalachian State University's Institutional Review Board for human subject experimentation. All the subjects had a minimum of 1 year of MMA fighting experience. Confidentiality of the data was strictly maintained with respect to each subject.

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Acute Weight Gain

The official weigh-in was held the day before the event approximately 24 hours before the fight. Actual body mass (kilograms) was obtained for all fighters using a calibrated digital scale (Tanita Corporation of America, Arlington Heights, IL, USA), that is, official weight. The boxing commission personnel on site recorded all body mass measurements. In both North and South Carolina, the boxing commission regulates all rules and policies associated with MMA competition.

Approximately 22 hours after the official weigh-in, and approximately 2 hours before the start of competition, all fighters were reweighed to determine the body mass at the time of competition, that is, fight weight. All reweighing was done on the same scale that was used to determine the official weight. Using the official weight and fight weight, the following variables were calculated (19):

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Body Composition Assessment

Body composition was assessed according to skinfold analysis (SK) methods for descriptive purposes only. The SK measurements were taken once at the official weigh-in. The SK measures were recorded with Lange SK calipers at 3 sites: triceps, subscapular, and abdomen. Body density (Db) was determined from the 3 SK measures using the prediction equation

(13). Percent body fat (%BF) was determined from Db using the Brozek equation (6).

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Hydration Status Assessment

Each fighter supplied a urine sample immediately before each of the body mass assessments. The urine was placed in a plastic cup, and the specific gravity (Usg) of the samples was determined by an optical refractometer (NSG Precision Cells Inc., Farmingdale, NY, USA). Once the urine samples were analyzed for Usg, they were immediately discarded.

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Statistical Analyses

Statistics were analyzed using SPSS software. Descriptive statistics were used to characterize the subjects. A repeated-measures 1-way analysis of variance was performed to detect significant differences in body mass and Usg. Pearson product moment correlations coefficients were used to examine and compare the changes in body mass to Usg. Significance was set at a p value ≤0.05 for all variables.

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Descriptive data for mean baseline subject characteristics are found in Table 1. Significant differences (p < 0.001) were found in body mass from the official weigh-in to 2 hours before competition. Body mass increased by 3.4 ± 2.2 kg or 4.4% in the approximately 22-hour period before competition (Figure 1). A significant decrease (p < 0.001) was also found for Usg from the official weigh-in to 2 hours before competition. The Usg decreased from 1.028 ± 0.001 to 1.020 ± 0.001 (Figure 2).

Table 1

Table 1

Figure 1

Figure 1

Figure 2

Figure 2

Results further demonstrated that 39% of the subjects were significantly dehydrated (Usg > 1.021), and of those subjects 11% were seriously dehydrated (Usg > 1.030) when assessed 2 hours before competition (Figure 3). It was also determined that only 23% of the subjects were classified as “well hydrated” (Usg < 1.010) in the 2-hour period before competition. No significant correlations were found between the changes in body weight and changes in Usg throughout the investigation.

Figure 3

Figure 3

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The results of this study are the first to measure dehydration and AWG in MMA fighters before competition. The findings of the present investigation are similar to previous investigations of amateur wrestlers (12,16–19). Our results indicate that in the time period between the official weigh-in to just before competition (∼22 hours), AWG was 3.4 ± 2.2 kg or 4.4% of the body weight. These results are consistent with the findings of Scott et al. (19) who measured the magnitude of AWG in collegiate wrestlers between the official weigh-in and competition (∼20 hours) at the 1992 National Collegiate Athletic Association (NCAA) Division I wrestling tournament. The results of that study found on average that AWG was 3.7 ± 1.3 kg or 4.9% of the body weight. Results of the current investigation are also in agreement with data reported in a study by Alderman et al. (1). In their study, AWG was measured in 2,638 HS Freestyle (international style) wrestlers. Results found that HS Freestyle wrestlers gained on average 3.4 kg, which represented 4.81% of the body weight. The results of the present investigation should be viewed in comparison to the recently reported 0.9 ± 0.8 kg or 1.3 ± 1.2% AWG found in 811 collegiate wrestlers during the 1999–2004 NCAA championships after the implementation of NCAA's weight management program, which demonstrated significantly less AWG and unhealthy weight loss behaviors (17). The similarity in AWG between MMA athletes and wrestlers suggests that weight management policies like those recently implemented by the NCAA and the National Federation of State High-School (NFHS) Association for wrestling are warranted for MMA.

In the present investigation, hydration status was measured by means of urine specific gravity (Usg), which was found to significantly decrease from 1.028 ± 0.001 to 1.020 ± 0.001 from the time period between the official weigh-in and just before competition. The NCAA and others have chosen a Usg measurement of ≤1.020 to identify a state of euhydration (7,10,21) for weight certification and physiological purposes. Zambraski et al. (21) measured changes in the urinary profiles of HS wrestlers before competition at the state HS championships. In that study, the Usg values on average were 1.028 ± 0.0007 at the official weigh-in. Just before wrestling (∼5 hours after official weigh-in), Usg values on average were 1.026 ± 0.0005 indicating that the subjects were not in a euhydrated state just before competition. These findings are similar to those of our study in which Usg values averaged 1.028 ± 0.001 at the official weigh-in indicating dehydration via urinary measures. As highlighted in the National Athletic Trainer's Association position paper, a Usg value > 1.021 is associated with significant dehydration (7).

Rapid weight loss is a concern for MMA fighters because it can ultimately lead to dehydration-related health issues and impaired performance. Results of this study demonstrated that 39% of the subjects were significantly dehydrated (Usg > 1.021), and of those subjects, 11% were seriously dehydrated (Usg > 1.030) when assessed just 2 hours before competition. One subject in this study demonstrated an AWG of 9.81 kg or 10% of his body weight in the approximately 22-hour period before competition. This value is consistent with the 6.7–10% of rapid weight loss demonstrated by the collegiate wrestlers in 1997, which resulted in heat-related deaths (8). Aside from the health consequences, dehydration or excess body water loss has negative physiological implications that impair performance capabilities (2,7,20). Recent attention has been given to the strength and conditioning considerations of MMA athletes (5). Future research should employ studies to investigate the effects of acute dehydration on the performance attributes of MMA athletes.

Although there is a paucity of research on dehydration-related health or performance effects before, during or after an MMA event as a result of intentional rapid weight loss, the previous tragedies in collegiate wrestling coupled with the results of this study warrant regulation of “weight cutting” practices in MMA athletes. The MMA is a unique sport that does not have a specified “season” and lacks a national governing body such as the NCAA. Competition rules and official weigh-in procedures vary state to state within the USA, and as such, it is difficult to make overarching weight management recommendations for MMA from a national perspective. However, wrestling weight management recommendations from the American College of Sports Medicine (15) and similar weight-classified sports can provide possible regulatory changes that could be implemented within the MMA community. In one such sport, Judo, a martial art integrated into MMA, a recent study that demonstrated rapid weight loss practices by its 822 competitors found that 86% reported that they have lost weight to compete with an average reduction of 5% of their body weight (4). Using the experience and research from the scientific wrestling community and combining it with the current practices of Judo competitors, weight management regulations for Judo have been proposed (3).

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Practical Applications

Overall, it is evident from the results of the present investigation that MMA fighters undergo a significant amount of AWG from the official weigh-in to just before competition as a result of rapid weight loss confirmed through significant changes in body weight and Usg. It was found that 39% of fighters recorded a Usg value >1.021, indicating that the athletes were competing in a dehydrated state. It has been reported in other combative sports, that is, wrestling, that dehydration inhibits performance and results in health risks that can potentially lead to untoward health events including death. The sport of wrestling has previously faced personal tragedy that threatened its existence in 1997 when 3 athletes lost their lives as a result of intentional dehydration. The subsequent rule changes implemented by the NCAA and the NFHS athletic associations have assisted in preventing additional health-related incidents in the sport of wrestling in the USA.

Other combative sports such as Judo and International-style wrestling have similar weight management issues than those that were identified in the current investigation with MMA athletes. The individuals who are the most influential in teaching athletes strategies for weight loss are typically the coach, training partners or former athletes (11). Because the coach is generally the most frequent source of information for athletes, educational programs should focus on providing them with full explanations of how to properly advise MMA fighters about health weight management procedures. Results of the present investigation demonstrate that weight management regulations for MMA competitors are warranted to aid in preventing adverse health events (i.e., exertional rhabdomyolysis, hyperthermia, and death) that have previously been documented in the sport of wrestling. MMA governing bodies at the national and international levels along with coaches should take a proactive approach in education and implementation of weight management regulations that prevent rapid weight loss among MMA athletes.

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Funding was provided by the Appalachian State University, Office of Student Research.

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wrestling; combative sports; body composition; fat-free mass; body fat; rapid weight loss

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