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physics

Weight cutting

Weight cutting is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Weight cutting rather than just read about it. In short: Weight cutting is the practice of fast weight loss prior to a sporting competition. It most frequently happens in order to qualify for a lower weight class or to meet the maximum weight limit in their weight class if one exists (usually in combat sports or rowing, where weight is a significant advantage) or in sports where it is advantageous to weigh as little as possible (most notably equestrian sports).

Weight cutting — main illustration
Weight cutting — illustration

Key takeaways

  • Weight cutting belongs to physics; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Weight cutting to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Weight cutting from memory before moving on to harder problems.

Reference excerpt

Weight cutting is the practice of fast weight loss prior to a sporting competition. It most frequently happens in order to qualify for a lower weight class or to meet the maximum weight limit in their weight class if one exists (usually in combat sports or rowing, where weight is a significant advantage) or in sports where it is advantageous to weigh as little as possible (most notably equestrian sports). There are two types of weight cutting: one method is to lose weight in the form of fat and muscle in the weeks prior to an event; the other is to lose weight in the form of water in the final days before competition. Common methods to cut weight include restricting food intake, water-loading, and perspiration through exercise, wearing a sweatsuit, and/or sitting in a sauna. Nutritional experts rarely give advice on how to cut weight safely or effectively, and recommend against cutting weight; however, many athletes choose to do it because they wish to gain an advantage in their sport.

Weight cutting in combat sports Weight cutting has been known as "dangerous" when losing large amounts of weight in a short period of time by using a sauna, wearing a sweat suit, by severely dehydrating, and "water loading". In December 2015, 21-year-old Chinese mixed martial artist Yang Jian Bing died due to dehydration when weight-cutting for a fight put on by Singapore-based ONE Championship. ONE Championship banned weight-cutting by dehydration later that month and now holds fights based on a competitor's "walking weight", rather than pre-fight weigh-ins. The promotion's revised policy on weight mandates that athletes are monitored in their training camps, and have urine specific gravity tests to ensure they are hydrated up to three hours ahead of their bouts. The new system has been well received by athletes and other stakeholders in the MMA industry. This new implementation puts a greater emphasis on safety which is beneficial for the competing athletes. In March 2016 Scottish Muay Thai fighter Jordan Coe died in Thailand when he was trying to cut weight for a fight. In November 2017 Australian Jessica Lindsay died after extreme weight cutting for Muay Thai fight in Perth, WA. Belfast-born acute care physician Paddy Golden has warned the Combat Sports Commission in Western Australia about the risks of weight cutting. In December 2017, Golden stated that putting one's body through acute water loss was "very dangerous", and called for measures to tackle it across Australia. In June 2018 Dr Golden stated that unless regulation is put in place to stop extreme weight cutting, deaths were "inevitable". At the end of 2017, it was reported that Golden had called for athletes to undergo hydration tests, which would dictate whether they should be allowed to participate in bouts. Some state athletic commissions have suspended fighters who have been caught cutting weight in an unhealthy manner. For instance, the Mohegan Tribe Department of Athletic Regulation suspended Adam Piccolotti for six months after he posted a video of himself vomiting in an attempt to cut weight prior to Bellator 274; he was also fined $2,500, although the outcome of the match was not overturned.

Dieting In addition to improving performance through healthy eating, some athletes will seek to lose weight through dieting and aerobic exercise. By losing fat, they hope to achieve a higher "strength-to-mass ratio" or "lean weight". This means more muscle and less fat, and should theoretically give them an advantage against other athletes of the same weight. Dieting is a common way for combat athletes to lower their weight in order to make their desired weight class.

See also Human weight Weight loss Eating disorder Dieting Healthy eating Dehydration Rehydration Aerobic exercise Strength training

References

Illustrations

Weight cutting: Manny Pacquiao weigh-in
Manny Pacquiao weigh-in

Worked examples

Example 1 — a first encounter with Weight cutting

Start with the simplest possible case. Write down what Weight cutting claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Weight cutting before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Weight cutting ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Weight cutting

In research
Weight cutting appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Weight cutting in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Weight cutting is common in secondary-school and first-year university syllabi. It links to neighbouring topics Combat sports controversies, Human body weight, Physical exercise, so understanding it makes those chapters shorter.
In everyday life
Look for Weight cutting outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Weight cutting in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Weight cutting means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Weight cutting out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Weight cutting in simple terms?

Weight cutting is the practice of fast weight loss prior to a sporting competition. It most frequently happens in order to qualify for a lower weight class or to meet the maximum weight limit in their weight class if one exists (usually in combat sports or rowing, where weight is a significant adva…

Why does Weight cutting matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Weight cutting?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Weight cutting.

Tags

  • Combat sports controversies
  • Human body weight
  • Physical exercise
  • Sports nutrition

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