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Rapid weight loss (weight cutting) by dehydration is a dangerous practice often undertaken in combat sports. Contestants rapidly decrease their body weight before weigh-ins through excessive dehydration, for the purposes of gaining an advantage by competing
in a weight class below their normal fighting weight.
Contestants then attempt to regain the lost weight in the time between the weigh-in and the contest (usually about 24 hours in Western Australia), with the intention of being heavier than their opponent in the contest.
Many physiological and psychological symptoms demonstrate that weight cutting by dehydration is harmful to all contestants.
In addition, while contestants may be able to regain most or all of the rapidly lost weight, there is research to suggest that contestants are not adequately hydrated at the time of the contest, so creating an increased risk of injury, which can prove
The Combat Sports Commission (the Commission) has developed a Strategy to address this dangerous practice which is outlined in this Executive Summary and in greater detail at the end of this report. The Commission is keen to provide the safest possible
environment for combat sports in Western Australia.
In the development of the Strategy, the Commission provided opportunities for relevant stakeholders to assist in the shaping of the Strategy. The Commission contacted all registrants to participate in the consultation process. The Commission conducted
initial one-to-one interviews followed by a series of workshops. The Commission thanks all those involved in the consultation process to date for their time and effort in assisting to make combat sports in Western Australia safer.
The Commission has released this report for further public comment and welcomes any feedback in relation to any aspect of the report or Strategy. The public comment period will close on 31 January 2019.
Please send all comments to the Combat Sport Commission using either of the following methods:
The Commission undertook extensive research into the many aspects of weight cutting including:
The research identified many dangerous health impacts caused by weight cutting, including:
The effect on performance in the contest is a complex and multivariate subject where more study is needed. However, the indications from the available research is that there is a statistically significant decrease in aerobic and anaerobic performance
from weight cutting.
The Commission engaged a team from the Curtin University School of Physiotherapy and Exercise Science Centre for Sport and Recreation Research to undertake a review of all relevant literature, to determine the validity and practicality of dehydration
testing in a short space of time in a combat sport environment.
The review found that there are many methods to monitor the hydration status of an individual with varying degrees of accuracy and practicality. The methods that are accepted as highly accurate are not often practical, and methods that offer more practicality,
are less accurate.
The Commission canvassed other combat sports jurisdictions to identify the measures that are being imposed around the globe to address weight cutting.
The Strategy to address weight cutting is outlined below. The Strategy has been developed after extensive deliberation over all the options available to the Commission.
The Commission will undertake an evaluation of the success of the Strategy after it has been in effect for at least six-months. If the evaluation concludes that the dangerous practice of weight cutting is continuing, then the Commission may impose a strict
secondary weigh-in or same day weigh-in or any other amendments it deems necessary.
The Strategy is based on the following four pillars:
Written by participants of the industry consultation.
Our opportunity is to deliver the safest possible environment for combat sports participants that is manageable for promoters and trainers. We will do this by developing and implementing a comprehensive range of practical and cost-effective strategies,
which results in a mindset change amongst all stakeholders to the combat sports industry, with regard to weight cutting by dehydration. Safety First Always.
As part of the Project, there were a number of opportunities for interested parties to participate in the development of the Strategy.
An expression of interest was sent to approximately 1,300 Commission registrants, offering the opportunity to be part of the Project. The participation in the consultation was as follows:
The Commission devised a series of questions aimed at gathering information on the culture, the perceptions and the drivers of weight cutting and ideas on how to address the issue. The overall sentiment from the responses was an overwhelming desire for
change from the existing weight cutting culture.
Some of the comments from the consultation are below.
Weight cutting culture
Driving forces behind weight cutting
Ideas to address weight cutting
Following the one-to-one interviews, an industry workshop was held over two sessions with nine people from the consultation group in attendance. A summary of the one-to-one interviews was presented.
The purpose of the workshop was to:
Develop an opportunity statement (written by participants)
“Our opportunity is to deliver the safest possible environment for combat sports participants that is manageable for promoters and trainers. We will do this by developing and implementing a comprehensive range of practical and cost-effective strategies,
which results in a mindset change amongst all stakeholders to the combat sports industry, with regard to weight cutting by dehydration. Safety First Always.”
Define the success of the project (comments from participants below)
Identify measures of success (comments from participants below)
A second workshop was held over two sessions after the development of an interim Strategy. The interim Strategy was presented, debated and refined with the five people from the consultation group in attendance.
The purpose of the June workshop was also to assess the critical success factors that were developed at the first workshop, which were identified as being critical components to the success of the Strategy. The attendees discussed the components that
had been included and excluded as part of the Strategy and the reasoning and consideration that had occurred around these decisions.
Table 1: Second Workshop - Critical Success Factors
There is a significant amount of academic literature available on the health effects of rapid weight loss and severe hydration. However, there is limited research on the performance effects from these conditions, particularly in a combat sport environment.
A review of the relevant literature was conducted to gather the information relevant to the development of the Strategy. The literature review is presented below with key information, messages and ideas from the relevant articles.
Results of the study:
Table 2: Weigh-in Time vs Weight Loss
Weight typically regained between weigh-in and competition (kilograms)
Time between weigh-in and competition (hours)
*This table has been simplified for the purposes of this report. See the full article for the complete table.
Psychological effects of rapid weight loss:
Physiological effects of rapid weight loss:
Some extreme cases:
No athletes are allowed to compete in a weight class that would require weight loss greater than 1.5% of body mass per week.
The Commission engaged a team from the Curtin University School of Physiotherapy and Exercise Science Centre for Sport and Recreation Research to undertake research into the validity and reliability of clinical measures to detect severe dehydration and
the practicality of applying these measures in a combat sports setting. A summary of some of the key and relevant points from the literature review are below.
Between 31 March 2017 and 24 September 2017, the Commission collected secondary weigh-in data, from 426 contestants, at 15 events, encompassing various sports as shown in the below table.
Table 4: Secondary Weigh-in Data Collected by Sport
Contestants were weighed immediately prior to the event, in addition to the standard weigh-in which normally occurs approximately 24 hours prior in Western Australia.
An analyst from Edith Cowan University was engaged by the Commission to undertake a statistical analysis of the data.
The data was split into percentage weight variation categories (weight change between the first and second weigh-ins) at 1% intervals.
Table 5: Number of Contestants by Weight Variation Categories
The data was then analysed in terms of weight difference and the success of contest outcomes. The table below shows the win percentages of contestants in Muay Thai, boxing and MMA at each different weight difference category.
Table 6: Win Percentage by Weight Difference Category by Sport
The overall conclusion from the analysis is that the results vary and are inconsistent depending on the sport and weight cut that is observed. Consistent with other research presented in this report, the results of this study show that under certain circumstances,
weight cutting can give competitive advantage however under different circumstances it may hinder performance and prove to be fatal.
The CSAC regulates professional and amateur boxing, kickboxing and MMA throughout California by licensing all participants and supervising the events. The Commission is dedicated to the health, safety and welfare of the participants in regulated competitive
sporting events, through ethical and professional service.
The CSAC approved the 10-point plan to curb severe dehydration and weight cutting for MMA athletes on 16 May 2017.
Examination and education for matchmakers, promoters, trainers and athletes on offering, accepting and contracting bouts.
The AAC established reforms to address weight cutting in effect from 5 August 2018.
Executive Director Jody McCormick commented that “Alabama’s changes are on a smaller scale than California’s, which is appropriate, given the relative sizes of the two commissions.”
The reforms are as follows:
Director of Operations for the Brazilian MMA Athletic Commission, Christiano Sampario, argues that “the timing of weigh-ins won’t address the problem of weight cutting at the scale that exists in combat sports. Giving fighters a wider target
within divisions will.”
The Brazilian Commission has been collecting data on fighters and weight from events it has regulated – including four UFC events – since it adopted the California State Athletic Commission’s 10-point plan on weight-cutting in July 2017.
“One of its key takeaways from the numbers, Sampaio said, was the need to change the definition of the currently accepted weight classes. Rather than a division’s weight representing a limit, it should mark a starting point that cuts off
at the next highest division.”
Sampaio said “allowing a higher range of weights – while still keeping the numbers associated with current divisions – will encourage fighters to compete closer to their natural mark and keep them from coming into the cage dehydrated.”
IFMA is the sole recognised sport governing body of amateur Muay Thai consisting of 130-member countries worldwide with five continental federations. In 2017/18, IFMA issued an update to its medical check procedure for all athletes which had
a focus on weight cutting and dehydration.
Medical Declaration Form
IFMA rule 6.1.3 states that:
“All athletes competing at all IFMA international level events must have completed the IFMA Athlete’s Medical Declaration form signed by their doctors prior to leaving their home countries for an event. This form must be duly completed
and submitted together with their boxer’s book at weigh–in.”
The IFMA medical declaration includes:
The declaration also includes the following messages to the athlete/coach/guardian:
ONE Championship (formerly known as ONE Fighting Championship or ONE FC) is a Singapore-based MMA promotion which was launched on 14 July 2011.
In December 2015, 21-year-old Chinese contestant, Yang Jian Bing, passed away as he was cutting weight for ONE Championship's 35th event. Less than two weeks later, the promotion implemented changes to the weigh-in system to improve health and safety.
The policy is as follows:
The usage of IVs for the purpose of rehydration will not be allowed.”
The NCAA is a non-profit organisation which regulates athletes of over 1,200 North American institutions and conferences.
At the start of the pre-season, wrestlers have their body fat percentage assessed, which is in turn used to determine the minimum weight at which they are allowed to compete. The minimum weight set is at 5% body fat for men and 12-14% for women.
Further, wrestlers are allowed only to lose a maximum of two pounds a week (approximately 0.9 kg/wk) from the start of the pre-season to the date of their competition. Weigh-ins are conducted one or two hours prior to the event.
The NCAA uses urine specific gravity of 1.020 or less to ensure wrestlers are hydrated when being assessed for their minimum weight.
Any contestant failing to make weight at the designated time shall be ineligible for that weight class.
The NFHS is the body that writes the rules of competition for most high school sports and activities in the United States.
The NFHS implemented new rules from the beginning of 2006-07 season to discourage rapid weight loss.
Beginning in 2006-07, each state association shall develop and utilise a weight management program that includes:
The University Interscholastic League (UIL) is an organisation that creates rules for and administers almost all athletic, musical, and academic contests for public primary and secondary schools in the American State of Texas.
Since 1910, the UIL has grown into the largest inter-school organisation of its kind in the world.
The UIL has implemented rules in line with the NFHS and also implements minimum weights at which an athlete can compete.
The UIL does not advocate that a wrestler’s established minimum weight is the athlete’s best weight at which to wrestle, but simply the minimum weight at which the athlete will be allowed to compete.
Two key components of the UILs rules are the hydration assessment and the minimum weight class certification.
In order to obtain a license or the renewal of a license, all boxers must submit to a thorough medical examination by a physician approved by the Boxing Commission.
The following minimum physical requirements and disqualification shall apply to professional boxers (unless contrary to law of a given region).
No rapid dehydration. If a boxer is more than 5% overweight five days before a fight, he should not be allowed to dehydrate himself and should not be permitted to fight. If he presents signs of dehydration or excessive loss of weight on the day of
the fight, he should not be permitted to fight.
The ring physician or physician designated by the local commission shall follow the procedures listed below:
(b) Physical Examination:
(xvi) Weight Loss: The Ring Physician shall pay particular attention to the presence of debilitating effects resulting from a strenuous weight loss program, both by foods or fluid reducing drugs, which might weaken the boxer to the extent he should
be precluded from boxing in that particular event.
The final and official weigh-in of the boxers shall occur no less than 24 hours but not more than 30 hours prior to a WBC bout due to the possible adverse results of dehydration and subsequent rehydration of boxers to make the required weight
limit for a bout.
Further, in order to encourage safe weight loss in advance of a WBC bout, additional official safety weigh-ins are to be held 30 and seven days prior to the official 30-24 hour weigh-in for non-heavyweight boxers. The boxers’ weight should be
(a) 30-day weigh-in: 4 weeks prior to the bout, the boxers’ weight should not exceed 10% of the weight limit for the bout; and
(b) 7-day weigh-in: seven days prior to the bout, the boxers’ weight should not exceed 5% of the weight limit for the bout.
In the event that a boxer exceeds any weight limitation stated above, the WBC may, for the safety of the boxer or his opponent, revoke or deny its sanction of the bout, in addition to any other disciplinary action as it shall deem appropriate in its
When necessary, the WBC may require fat tissue laboratory exams on boxers with weight issues to assess their rating in certain weight divisions, and more importantly to protect their health by not allowing their participation in bouts in weight divisions
which could put their health in danger.
The local boxing commission has the responsibility to arrange for and conduct physical examinations prior to all WBC-sanctioned bouts at the weigh-in ceremony, which shall occur for all weight divisions including heavyweight. The exams shall include:
…direct questioning about the use of any medicines or drugs, or any artificial means for weight reduction.
The local commission medical panel and/or the WBC Supervisor(s) upon the advice of a licensed physician may arrange for the collection of blood and/or urine samples or any other exam if, in the pre-bout medical examination, signs of serious dehydration
or drugs are detected or are suspected.
The Strategy to address rapid weight loss (weight cutting) by dehydration has been developed by the Commission after extensive research and consultation with the industry and Curtin University. The Commission is of the view that the Strategy will
significantly improve the safety of combat sports in Western Australia. The Commission will undertake an evaluation of the success of the Strategy after it has been in effect for at least six-months. If the evaluation concludes that the dangerous
practice of weight cutting is continuing, then the Commission may impose a strict secondary weigh-in or same day weigh-in or any other amendments it deems necessary.
The Strategy is constructed upon four pillars:
The Curtin University Reportexamined the validity, reliability and practicality of dehydration assessment. The reviewed methods of dehydration testing suitable to be used in the
field (e.g. handheld refractometers, subjective assessments) lack sufficient validity and reliability to rapidly and correctly diagnose the hydration status of many individuals at weigh-in and competition.
The report states that a combination of field-based hydration tests is likely to enhance the ability to determine an individual’s hydration status.
The report recommends that the implementation of any hydration test in the field should be conducted by an experienced professional and that the equipment used to obtain or analyse biological samples be calibrated, cleaned and operated correctly in
an appropriate setting (i.e. sterile, appropriate lighting) to ensure that the most valid and reliable results are obtained.
The report also recommends that the implementation of any hydration test should be carefully considered with an appropriate level of dehydration chosen to minimise false classifications, particularly the false classification of euhydration (neutral
On the basis of the report, all contestants must be clinically assessed by a medical practitioner, which may be validated by a urine specific gravity (USG) test. USG is a measure of the concentration of salts in urine comparing specific gravity of
urine, with the specific gravity of water. Medical practitioners identify the symptoms and signs of dehydration, then if considered appropriate, the medical practitioner can verify the assessment with a USG test.
The validity of USG testing was questioned in the Curtin University Report as it has a high rate of false positives (hydrated individuals are often misclassified as dehydrated). The literature also reports an 80% (higher in some studies) accuracy
in identifying dehydrated people. These factors contribute to the report’s assertion that this method is not suitable as a sole measure for field testing. By sampling only dehydrated individuals (based on a medical practitioner’s clinical assessment), the potential for misclassifying
hydrated individuals is reduced, so the validity and reliability can be maximised.
Ultimately, there is no perfect method to assessing or identifying dehydration. So, an integrated approach utilising a clinical assessment by a medial practitioner at the ‘pre-contest’ medical assessment, together with the USG test would
improve validity and accuracy of the diagnosis.
Authority: s.33A, s.49A Combat Sports Act 1987
Pre-contest medical assessment
Why use 1.025 as the urine specific gravity threshold?
The existing weigh-in rules do not discourage contestants from gaining as much weight as possible between the weigh-in and contest (approximately 24 hours) which can be in excess of 5% body weight for many contestants, based on secondary weigh-in
data captured by the Commission throughout 2017. The new weigh-in process will address this issue and will create a more equitable and safe environment for combat sports in Western Australia.
Authority: s.45, s.48 and s.62A Combat Sports Act 1987
Single Weigh-in Attempt
Rules will be amended so that contestants will no longer have multiple attempts to make weight within the two-hour window of the weigh-in. Contestants will only have one attempt to make the relevant weight. The current process incentivises rapid weight
loss by dehydration by compelling contestants that weigh over the agreed maximum weight to rapidly lose additional weight through dehydration prior to weighing in again within the two-hour time limit. Contestants will weigh-in wearing minimal
clothes which is consistent with current rules.
Weight Classes Only
The Commission will no longer approve catch weights (agreed weights) and will only allow contestants to compete within the approved relevant weight class.
Contestants will be able to compete at any weight within that relevant weight class.
Weight classes are imposed for the health and safety of contestants to ensure that similarly weighted contestants are matched together. Catch (agreed) weights are a way to circumvent the weight classes that are set out in the Combat Sports Regulations
2004 or the approved rules of sanctioning bodies.
Contestants will be encouraged through education to aim for the middle of the relevant weight class rather than the upper limit which will increase the risk of weighing outside the weight class.
Rules and permit conditions will be amended so that contestants weighing over the maximum weight or under the minimum weight of the relevant weight class will not be permitted to compete. If contestants are weighing outside the range of a weight class,
then this is a strong indication that they are attempting to compete in a weight class that is not appropriate for their body type. With the enforcement of strict weight classes, there will be an incentive for contestants to compete closer to
their normal fighting weight.
If approved sanctioning body weight classes vary from Commission rules, then the sanctioning body weight classes will apply.
Secondary Weigh-in (Data Collection)
The Commission will require all contestants to undertake a mandatory secondary weigh-in at the contest for the purposes of collecting data by which the Commission can evaluate the success of the Strategy in curbing the dangerous practice of weight
While the secondary (contest) weight will be used for data collection purposes, the Commission will enforce its health and safety oversight in extreme cases where excessive weight gain causes a mismatch between opponents.
The Commission may escalate the Strategy via a strictly enforced secondary weigh-in or move to a same day weigh-in if the dangerous practice of weight cutting continues after the introduction of the Strategy.
The Certificate of Fitness will be amended to include some questions about proposed contest weight class, past contest weight class and walking weight and a question for the medical practitioner to consider whether the proposed weight class is reasonably
achievable for the contestant based on all available information.
Authority: s.16 Combat Sports Act 1987, r.8A Combat Sports Regulations 2004
Authority:,s.10(1)(b), s.10(1)(d), s.23 Combat Sports Act 1987
The Combat Sports Act 1987 provides for the Commission to:
(b) formulate…codes of conduct…for the purpose of maintaining proper standards in combat sports;
(d) devise and approve…guidelines for the preparation or training of persons participating in or proposing to participate in contests.
The Commission will include the following wording in its Code of Conduct to prohibit rapid weight loss by dehydration:
There should be no attempt to ‘make weight’ by any artificial means to dehydrate, as such means increase the risk that contestants may be seriously or even fatally injured during contests.
In the interests of contestant safety, the Commission prohibits the use of heat suits, saunas and any other device which purposely increases body temperature and/or dehydrates the contestant.
The Commission also prohibits the use of intravenous therapies which are used for aiding rehydration from excessive and deliberate dehydration.
Any promoter, trainer, or other person registered with the Commission found to be encouraging the use of such methods will be sanctioned by the Commission. Any contestant known to be using these methods will not be allowed to compete.
Inserting the above wording into the Code of Conduct will allow the Commission to impose disciplinary procedures under section 23 (contestants) or 33A (industry participants) of the Combat Sports Act 1987 such as suspension or cancellation of registration.
The Strategy includes a strong focus on industry education as a means of improving safety and shifting the culture of combat sports away from the dangerous practice of rapid weight loss by dehydration.
Authority: s.17 Combat Sports Act 1987
Under the Strategy, all people that register with the Commission will be required to undergo an online education assessment which will ensure that registrants attain a minimum level of knowledge prior to competing or participating in combat
sports in Western Australia. The assessment will apply to all classes of registration and the content will be modified according to the relevant class (contestant, trainer, official etc).
The assessment content will be broader than weight cutting and may include:
Authority: s.10 Combat Sports Act 1987
Once registered with the Commission, a registrant will be issued with introduction materials in the form of a brochure containing relevant information and links to other resources. This may also include information covered in the mandatory online
The Commission will distribute a brochure to the industry focused around weight cutting and the final Strategy.
Authority: s.35 Combat Sports Act 1987
The Commission will include information about the dangers of weight cutting in the Contestant Record Book in addition to any other relevant health and safety information.
Guidelines will be updated to reflect any new findings, outcomes and advice regarding the Strategy.
Pursuant to Regulation 6A of the Combat Sports Regulations 2004, a person who is registered or licensed under a law of a place outside of the State, the purpose of which substantially corresponds with the purpose of the Act, as a contestant, is
to be taken to be registered under the Combat Sports Act 1987 as a contestant.
As such, interstate and international contestants that are not registered in Western Australia are not subject to all components of the Strategy, such as the mandatory online education assessment.
However, all contestants including interstate and international contestants will be subject to the following components of the Strategy which will ensure that there is equality and safety for all contestants regardless of origin:
The consultation group identified several measures to address weight cutting, however some were excluded from the Strategy for various reasons as set out below.
There are two common methods of body composition analysis which are used to measure bone, fat and muscle mass in the human body; bioelectrical impedance analysis (BIA) and dual energy x-ray absorptiometry (DEXA) scans.
DEXA scans are considered the gold standard in body composition analysis however accessing this technology can be difficult, expensive and the scans emit mild radiation which means that the service isn’t generally available for people under
18 years of age.
BIA is accessible and relatively cheap however studies have found varying degrees of accuracy for individuals, particularly for females.
Neither of these methods are suitable for incorporation into the Strategy at an overarching level, however either method may prove an effective tool for contestants and trainers in gaining valuable information about body composition to inform
safe weight loss and overall body composition.
Weight will inevitably fluctuate due to changes in diet, training intensity and during preparation for a contest, even excluding the body mass manipulation that occurs from weight cutting.
Ultimately, there is no single ‘ideal’ weight, so the Strategy removes any such ambiguity by not including weight monitoring and analysis.
The specific weight-based measures that were considered as part of the Strategy include:
The difficulty with many weight assessments is determining a safe weight and/or safe weight loss as this may vary for each individual. Some of the combat sports authorities such as ONE Championship and the NCAA place a strong emphasis on weight
monitoring and assessment, however these organisations have a greater role in monitoring the weights of contestants during seasons and outside of competition.
The Commission does not have the authority under the Combat Sports Act 1987 to monitor contestants out of the weigh-in and contest. Any data capture on weights outside of weigh-ins would be provided on a voluntary basis and as such would be incomplete
One other difficulty with weight monitoring and assessment is that it would only apply to a certain portion of contestants. International and interstate contestants that are competing in Western Australia are subject to different requirements
under the Combat Sports Act 1987 and as such would not be subject to all of the health and safety requirements that may be imposed on local contestants, which may result in mismatched contests.
However, the Strategy does not ignore the importance of weight. One of the main components of the Strategy is the strict enforcement of weight classes. The intent of this measure is for contestants to compete closer to their natural fighting weight
with the risk that weighing outside the weight class range would result in the contestant being ineligible to compete. There is an inherent penalty in this method that means that there is no need to move contestants up weight classes as they
will trend towards these naturally.
In addition, one other aspect to the Strategy is the inclusion of an amendment to the Certificate of Fitness whereby the medical practitioner is required to specify whether the intended weight loss is safe. The form will include fields to specify
walking weight, past contest weight/class and proposed contest weight/class.
Consideration was given to the establishment of a system of gym accreditation or a voluntary best practice acknowledgement by the Commission for gyms that were meeting certain conditions associated with best practice health and safety standards.
It was determined that this measure extended beyond the scope of the Commission’s power under the Combat Sports Act 1987 and as such was excluded from the Strategy.
The Commission has resolved to enforce a secondary weigh-in for the purposes of data collection. The Commission will use the data to evaluate the success of the Strategy in curbing the dangerous practice of weight cutting.
While the secondary (contest) weight will be used for data purposes, the Commission will enforce its health and safety oversight in extreme cases where excessive weight gain causes a mismatch between opponents.
Research has suggested that the amount of body mass that can be lost prior to a weigh-in and subsequently regained prior to the contest is reduced by same day weigh-ins.
Same day weigh-ins were considered for inclusion in the Strategy, however the Commission ultimately preferred the 24-hour weigh-in as part of the initial Strategy.
As mentioned above, same day weigh-ins remain a live option for the Commission and may be implemented at a later date as an alternative to the secondary weigh-in.
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