physics

Relative energy deficiency in sport

Relative energy deficiency in sport 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 Relative energy deficiency in sport rather than just read about it. In short: Relative energy deficiency in sport (RED-S) is a syndrome in which disordered eating (or low energy availability), amenorrhoea/oligomenorrhoea (in women), and decreased bone mineral density (osteoporosis and osteopenia) are present. It is caused by eating too little food to support the amount of energy being expended by an athlete, often at the urging of a coach or other authority figure who believes that athletes a…

Key takeaways

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

Reference excerpt

Relative energy deficiency in sport (RED-S) is a syndrome in which disordered eating (or low energy availability), amenorrhoea/oligomenorrhoea (in women), and decreased bone mineral density (osteoporosis and osteopenia) are present. It is caused by eating too little food to support the amount of energy being expended by an athlete, often at the urging of a coach or other authority figure who believes that athletes are more likely to win competitions when they have an extremely lean body type. RED-S is a serious illness with lifelong health consequences and can potentially be fatal. RED-S is the broader, more comprehensive name for what was formerly known as the female athlete triad (or simply the triad), which was a condition seen in females participating in sports that emphasize leanness or low body weight. As the non-menstrual components are also seen in males, the name was changed to the comprehensive term RED-S.

Classification Formerly known as the female athlete triad, RED-S is a syndrome of three interrelated conditions. Thus, if an athlete is suffering from one element of the triad, it is likely that they are suffering from the other two components of the triad as well. With the increase in female participation in sports, the incidence of a triad of disorders particular to women—the female athlete triad—has also increased. The female athlete triad and its relationship with athletics was identified in the 1980s as the prevalence increased during this period, and symptoms, risk factors, causes, and treatments were studied in depth and their relatedness evaluated. The condition is most common in sports that emphasize leanness, such as cross country running, gymnastics, figure skating and ski jumping. Many of those who suffer from the triad are involved in some sort of athletics, in order to promote weight loss and leanness. The competitive sports that promote this physical leanness may result in disordered eating and be responsible for the origin of the female athlete triad. For some women, the disorder can have major health consequences. In addition, for some competitive female athletes, problems such as low self-esteem, a tendency toward perfectionism, and family stress place them at risk for disordered eating.

Signs and symptoms Clinical symptoms of RED-S may include disordered eating, fatigue, hair loss, cold hands and feet, dry skin, noticeable weight loss, increased healing time from injuries (e.g., lingering bruises), increased incidence of bone fracture and cessation of menses. Affected athletes may also struggle with low self-esteem and depression. Upon physical examination, a physician may also note the following symptoms: elevated carotene in the blood, anemia, orthostatic hypotension, electrolyte irregularities, hypoestrogenism, vaginal atrophy, and bradycardia. An athlete may show signs of restrictive eating, but not meet the clinical criteria for an eating disorder. They may also display subtle menstrual disturbances, such as a change in menstrual cycle length, anovulation, or luteal phase defects, but not yet have developed complete amenorrhea. Likewise, an athlete's bone density may decrease, but may not yet have dropped below her age-matched normal range. These signs can be considered "occult," as no one symptom may be severe enough to seek medical attention, leaving the triad to go unnoticed or untreated. Although the larger scientific community has not agreed upon a clear recommendation for ideal energy intake, physicians may take note of female athletes consuming under 30 kcal per kilogram of fat free mass (FFM) per day.

Disordered eating

Energy availability is defined as energy intake minus energy expended. Energy is taken in through food consumption. Bodies expend energy through normal functioning as well as through exercise. In the case of RED-S, low energy availability may be due to eating disorders, but not necessarily so. Athletes may experience low energy availability by exercising more without a concomitant change in eating habits, or they may increase their energy expenditure while also eating less. Disordered eating is defined among this situation due to the low caloric intake or low energy availability. While most athletes do not meet the clinical criteria to be diagnosed with an eating disorder such as anorexia nervosa or bulimia nervosa, many still exhibit subclinical disordered eating, along with general psychopathology associated with eating disorders (anxiety, depression, obsessive-compulsive symptoms. Particularly, excessive fasting and avoidance of certain types of food (such as foods containing fat) arise commonly in athletes. Especially in weight-class sports, leanness-dependent sports, and aesthetic sports, the prevalence of eating disorders soar much higher than the average population. In athletes that engage in such sports, the pressure to perform promotes excessive dieting and other disordered eating habits, as athletes try to conform to expected weight patterns. More severe examples of disordered eating habits may include binge-eating; purging; and the use of diet-pills, laxatives, diuretics, and enemas. By restricting their diet, the athlete may worsen their problem of low energy availability. Having low dietary energy from excessive exercise or dietary restrictions leaves too little energy for the body to carry out normal functions such as maintaining a regular menstrual cycle or healthy bone density.

Amenorrhea

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Relative energy deficiency in sport

Start with the simplest possible case. Write down what Relative energy deficiency in sport 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 Relative energy deficiency in sport 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 Relative energy deficiency in sport 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 Relative energy deficiency in sport

In research: Relative energy deficiency in sport 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 Relative energy deficiency in sport 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: Relative energy deficiency in sport is common in secondary-school and first-year university syllabi. It links to neighbouring topics Medical triads, Sports medicine, Sports nutrition, so understanding it makes those chapters shorter.
In everyday life: Look for Relative energy deficiency in sport 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 Relative energy deficiency in sport in 20 minutes

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

Frequently asked questions

What is Relative energy deficiency in sport in simple terms?

Why does Relative energy deficiency in sport 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 Relative energy deficiency in sport?

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 Relative energy deficiency in sport.