NUTRITIONADVANCED CERTIFICATE: EXERCISE

SCIENCEHFPA

‘Proper nutrition is an important consideration for athletes who seek to maximise their performance. No diet directly increases strength, power or aerobic endurance but an adequate diet allows athletes to train and compete to the best of their ability’ (Baechle & Earle, 2008, p. 201).

ATHLETES AND NUTRITION

DEPENDS ON: Age Body size Sex Genetics Environmental training conditions Duration, frequency and intensity of training

Therefore the ideal diet for an athlete is one that is individualised.

IDEAL DIET

As an Exercise Specialist, you will spend many hours with athletes and thus you are in a perfect position to recognise signs of eating disorders and provide information about the athlete’s training to a Nutritionist.

YOUR ROLE

WHO IS AT RISK?

FOOD PYRAMID

A macronutrient is defined as a nutrient which is required in significant amounts in the diet. (Macro is defined as large scale by the Concise Oxford English Dictionary).

Three important classes of macronutrients are proteins, carbohydrates and lipids.

MACRONUTRIENTS

A micronutrient is a nutrient (vitamins and minerals) that is required in small amounts in the diet.

MICRONUTRIENTS

Water is crucial when exercising as it plays a role in thermoregulation. Thermoregulation is defined as the controlling of temperature at a core temperature of 37 degrees Celsius. The body generates heat (thermogenesis) when exercising and therefore the body needs to have ways of loosing this ‘excess heat’ as an increase in core temperature could cause heat damage. One of the ways in which heat is lost is through sweating i.e. water is secreted by sweat glands onto the surface of the skin and when this sweat evaporates it reduces the surface temperature.

FLUID AND ELECTROLYTES

http://www.enchantedlearning.com/label/

The rate of fluid loss (through sweating) can have an adverse effect on performance and is extremely dangerous because it causes dehydration.

The effects of dehydration are: fatigue, lowered blood pressure, lowered performance, increased body temperature, reduced urine output, increased pulse rate and circulatory collapse.

FLUID REPLACEMENT

Athletes should be well hydrated prior to beginning a workout or competition.

Athletes should consume 150-300ml of fluid every fifteen to twenty minutes during exercise.

Athletes should monitor fluid losses during exercise by monitoring body weight before and after exercise.

Monitor the colour of urine between workouts i.e. colour of lemonade then athlete is well hydrated whereas dark-yellow urine indicates dehydration.

Avoiding Dehydration

Purpose: Provide fluid and energy for the athlete during the performance.

Timing: 3-4 hours prior to the event Contact sports Lose appetite or feel nauseous Get diarrhea before or during event Exercise in heat High intensity sport

OR 30 minutes Hungry during an event Feel shaky or weak Aerobic – maximise stores

PRE-COMPETITION

What they like That they tolerate well That they are used to consuming That they believe result in a winnning

performance

PRACTICAL CONSIDERATIONS

Used to enhance muscle glycogen prior to long term aerobic endurance.

Most effective regime – three days with tapering exercise the week before competition and complete rest on day before competition.

Adequate calories with 600g of carbohydrate per day or 8 to 10g / kg of body weight.

Increase muscle glycogen stores 20- 40% above normal.

Benefits for: distance runners, road cyclists, cross-country skiers

Side-effects: increased water retention and weight gain, flatulence and diarrhea

CARBOHYDRATE LOADING

High GI replenish faster than low GI Directly after exercise??? Up to 8-24 hours

later. Balanced meal seems preferable – effective

way to achieve caloric intake and to enhance recovery.

POST-COMPETITION

Why? Improve physical appearance or enhace athletic performance.

Muscle mass = combination diet + progressive resistance training

But genetic predisposition, somatotype and compliance determine athlete’s progress.

Muscle tissue = 70% water+ 22% protein + 8% fatty acids and glycogen.

350 to 700kcal above daily requirements for 0.4 – 0.9 kg weekly gain◦ Larger portions◦ More items◦ Eat frequently – minimum 5 times a day◦ Higher caloric foods

WEIGHT GAIN

Why? Lower weight category or lower body fat Minimal body fat is largely genetic Well balanced diet with caloric deficit Loose body mass as well as lean body mass in athletes Gradual weight loss ensures maximum fat loss and

preservation of lean body mass. Not less than 1800 to 2000 kcal per day for athletes Foods high in nutrient density and low in energy density. Weight loss should occur in off-season or pre-season Self monitoring most effective for achieving weight loss

◦ Amount and type of food consumed◦ Feelings, times and places of intake◦ Exercise habits

WEIGHT LOSS

An ergogenic aid is defined ‘as work-producing substances or phenomena believed to increase performance’ (Powers & Howley, 2010, p.535). They therefore include nutrients, drugs, warm-up exercises, hypnosis, stress management, blood doping, oxygen breathing, music and extrinsic biomechanical aids. When Baechle & Earle (2008) – NSCA textbook -consider ergogenic aids they refer specifically to pharmacological aids such as: 1. hormones and drugs and 2. dietary supplements.

ERGOGENIC AIDS

Synthetic testosterone / pre-cursors for testosterone

Stimulate protein synthesis Stacking regime and cyclic regime Increased muscle mass, strength and

athletic performance.

ANABOLIC STEROID

Anabolic hormone Facilitate uptake of glucose and amino acids Increases protein synthesis Potentiate effects of growth hormone Side effect: Hypoglycaemia

INSULIN

Stimulates muscle and bone growth, maintains blood glucose levels, increases uptake of glucose and amino acids in muscle cells and release of fatty acids from fat cells.

Effects – gigantism and acromegaly

HUMAN GROWTH HORMONE

Elevations in haemoglobin and haemocrit Increases in RBC increases blood viscosity Risk of blood clotting, elevations in systolic

blood pressure and compromised thermoregulatory system.

ERYTHROPOIETIN (EPO)

Regulate lipolysis and thermogenesis. E.g. Clenbuteral (asthma medication)

Reduce anxiety and tremors during performance

Beta adrenergic agonists and Beta blockers

Creatine phosphate Saturation limit (150 -160 mmol / kg) 20 – 25 g daily for 5 days and then 2g per

day thereafter Reduce fatigue Increases in body weight No adverse effects accounted through

research

CREATINE

Caffeine◦ Central nervous system stimulant◦ Fat oxidation◦ Slows glycogen depletion and delays fatigue◦ Enhanced power production

Ephedrine◦ Thermogenic quality◦ Stacking agent with caffeine enhance effect

Citrus Aurantium◦ Appetite suppression◦ Increased metabolic rate◦ Lipolysis

STIMULANTS