Chapter 4: Diet, nutrition and the role of the energy systems

Link with the Coursework Planner (PAP): Following completion of section 4.1 and 4.2 each student could analyse their own diet and hydration using a food diary, urine chart and/or app. The necessary proformas and samples are provided in the booklet.

4.1 A balanced diet

Explain the main macro-nutrients including carbohydrate, fat and protein covering: • the role of each nutrient • where to find each nutrient (foods) • their importance for sport. – Ask the students to identify the most important nutrient for their sport.

Explain the main micro-nutrients including vitamins and mineral covering: • the role of vitamins and minerals • their application to sport e.g. calcium for strong bones to avoid injury.

NB: Students do not need to know the functions of each vitamin.

TASK 4.1 (Group work) ANSWER

Research the main dietary requirements for one of the following sportspeople and report your findings to the class:

– Marathon runner: High carbohydrate intake for energy; iron for RBC; calcium for strong bones; protein for recovery and repair of muscles; vitamins for energy production, immune function and blood circulation – Sprinter: Protein for muscle mass and recovery; moderate carbohydrate for energy; calcium for strong bones; vitamins for energy production, immune function and blood circulation – Jockey: Low carbohydrate and fat to maintain low body fat; protein for recovery; calcium for strong bones to avoid breaks when falling off; vitamins for healthy body function – GAA player: Carbohydrate as main energy source; protein to gain muscle mass and recovery; minerals for RBC and strong bones; vitamins for energy production, immune function and blood circulation – Sumo wrestler: High fat and high protein diet to increase body mass; calcium for strong bones to carry the large mass; vitamins to maintain general health – Weightlifter: High protein diet to maximise muscle bulk, low carbohydrate and fat to avoid fat gain prior to competition, calcium for strong bones to bear the weight, vitamins for good general health.

Outline the Apply it guidelines: Nutritional considerations for performance.

Discussion: Why do sportspeople need to take on additional macro-nutrients for training or competition lasting more than 90 minutes?

PRACTICE QUESTION ANSWERS

Q1. Identify two nutrients required for energy production. – Carbohydrate – Fat Q2. Explain the role of protein in our bodies. – Muscle repair and growth – Recovery from training e.g. micro-tears. Q3. What do you understand by the term balanced diet? – A diet with the right amount of calories and a variety of nutrients. Q4. Outline the importance of vitamins and minerals in our diet. – Vitamins help keep our bodies healthy e.g. skin, eyesight, bones, teeth, energy production, immune function, blood circulation. – Minerals contribute to the healthy functioning of our bodies including red blood cell production, nervous system, strong bones, hydration. Q5. Identify the key nutrients (macro and micro) required by each performer and justify your selections: (a) rugby front row: protein for muscle bulk, carbohydrate for energy, fat for extra protection from the high impact, calcium for strong bones (b) 50m sprint swimmer: carbohydrate for energy, protein for muscle bulk to increase power, vitamins and minerals for healthy body function (c) weightlifter: protein to increase muscle mass, carbohydrate for high-intensity energy, calcium for strong bones (d) Tour de France cyclist: carbohydrate for energy, protein for recovery, vitamins to maintain immune function and energy production, minerals such as iron to increase red blood cells.

Long answer question

Outline a set of nutritional guidelines for a named activity including specific advice for: (a) Before performance: the days leading up to competition and the hours before the start. (b) During the event e.g. in competition, during breaks, whilst on the move. (c) After the event: he hours immediately after the event.

Activity: GAA

– Before: Increase carbohydrate intake in the days leading up to the match in order to carbohydrate load. Consume antioxidants and beetroot in the form of juices in the week leading up to the event. – 3-4 hours prior to the match, consume a high complex carbohydrate meal to maximise energy stores; maintain good hydration; avoid sugary or fatty foods. – 1 hour before, consume an espresso or flat coca cola to increase caffeine levels. – During: Maintain hydration; consume a high-carbohydrate drink or gel at half-time to restore energy supply in the muscles; drink during breaks in the play. – After: Re-hydrate with water and electrolytes; drink a hypertonic recovery drink with protein; eat a meal high in carbohydrate and protein within one hour of the final whistle to take advantage of the increased metabolism.

4.2 Hydration for performance

Discuss the effect of hydration on performance including: – the negative impact of dehydration on performance – how to maintain hydration before, during and after performance.

TASK 4.2 (In pairs) ANSWER

Design a hydration plan for (a) a marathon runner (b) a GAA player. • Consider pre-event, inter-event and post-event hydration. • Type of drinks e.g. isotonic, Hypotonic, Hypertonic (see below)

Marathon runner

Pre-event: Ensure full hydration by regularly sipping water with electrolytes. Consume an isotonic drink 30 minutes prior to the start to pre-hydrate and boost glucose levels. During the event: Consume 150ml–200ml of a hypotonic drink every 20 minutes to maintain hydration and glucose levels. Post-event: Consume hypertonic drink to replace carbohydrate stores. Consume 1.5 litres of fluid for every kilogram of weight lost, by drinking regularly for several hours post-race.

GAA player

Pre-event: Ensure full hydration by regularly sipping water with electrolytes. Pre-hydrate with 300–500ml of an isotonic drink. During the event: Drink water during stoppages in play and consume an isotonic drink (500ml) at half-time to rehydrate and boost glucose levels. Post-event: Hypertonic drink to replace carbohydrate stores. Consume 1.5 litres of fluid for every kilogram of weight lost, by drinking regularly for several hours post-match.

Outline the sources of hydration including: – hypertonic, isotonic and hypotonic drinks.

PRACTICE QUESTION ANSWERS

Q1. Describe the difference between a hypotonic drink and a hypertonic drink. – Hypotonic = low carbohydrate (4%) – Hypertonic = high carbohydrate (10%) Q2. Explain what electrolytes are and how they affect hydration. – Electrolytes are salts and minerals such as potassium contained in the blood that help maintain hydration as well as nerve and muscle function. Q3. Investigate how hydration affects performance. Apply to an example. – Good hydration has a positive effect on endurance performance such as triathlon as temperature can be regulated, heart rate reduced and muscle function maintained. – Dehydration has a negative effect on endurance performance such as triathlon (2% dehydration = up to 10% reduction in performance) as temperature and heart rate will increase.

4.3 Sports supplements

Discuss sports supplements including: – their role in sport – the risks and challenges of using supplements.

TASK 4.3 ANSWER

Design a dietary table for one physical activity. Sport/activity: Football player

Primary source (Most important)

Source of energy Complex carbohydrate e.g. potatoes, pasta, bread Vitamins and minerals Fruit and vegetables to obtain a wide variety of vitamins

Protein Lean meat and fish

Secondary source

Unsaturated fat e.g. olive oil, nuts, seeds Meat and dairy e.g. iron and calcium

Beans and lentils

Hydration Water with electrolytes Isotonic drink at half-time

PRACTICE QUESTION ANSWERS

Q1. Outline three reasons why sportspeople use supplements. – In-competition energy replacement – Protein shakes for recovery – Additional nutrition – To extend performance (endurance). Q2. Describe two problems sportspeople may experience with supplement use. – Expensive and some are ineffective – Long-term health effects e.g. high-sugar energy drinks – Ethics. Q3. Examine the dietary requirements of a performer in one selected physical activity including: (a) the most important nutrients for the performer based on the requirements of the sport (b) maintaining hydration (c) nutritional requirements for competition before and during the competition. (d) nutrition for recovery (post training or competition).

Activity: Athletics – shot put

– Protein for muscle bulk, strength and recovery from weight training. – Carbohydrate for energy (explosive activity). – Hydration should be maintained by regularly sipping water; hydration is not a major consideration in shot-put performance as it is not an endurance event. – Pre-competition meal containing complex carbohydrate and lean protein. – During competition no additional energy intake is required. – A meal containing carbohydrate and protein should be consumed within one hour of competition to maximise recovery.

4.4 The energy systems

Introduction: Explain the difference between aerobic and anaerobic energy production. – Aerobic = energy produced with oxygen – Anaerobic = energy produced in the absence of oxygen – Discuss the advantages and disadvantages of each energy systems.

Explain the energy continuum with the help of the graph: – Anaerobic alactic (ATP-PC): very fast energy supply for around eight seconds – Lactic acid system: fast energy for up to 60 seconds – Aerobic energy system: slow energy for low-moderate intensity exercise; takes up to two minutes to reach its full potential due to the need for oxygen.

Compare the relative contribution of each energy system in selected events. (Use table 4.6.)

TASK 4.4 ANSWER

Look at the activities being performed in the images. Determine if it will be predominately the aerobic or anaerobic system supplying the energy. Family walk/jog = aerobic High jump = anaerobic Alactic/ATP-PC Rugby dive = anaerobic Alactic/ATP-PC Rowing (2000m/6 minutes +) = aerobic system will provide most of the energy with a significant contribution from the anaerobic lactic acid system.

TASK 4.5 ANSWER

Copy and label the diagram with: Aerobic, Anaerobic alactic (ATP-PC), Anaerobic lactic acid (LA).

Time

0 sec 10 sec 60 sec 90 sec 3mins 10mins

Alactic Lactic Acid Aerobic

TASK 4.6 ANSWER

Place each of the following athletics events into the most suitable box based on the predominant energy system.

100m

100% Anaerobic

400m 1500m 10,000m Marathon

50%

100% Aerobic

Video: Show the class the video of the energy continuum in action on the PowerPoint.

PRACTICE QUESTION ANSWERS

Q1. Describe the differences between aerobic and anaerobic energy production. – Aerobic energy production is the breakdown of glucose and fat in the presence of oxygen. – Anaerobic is the breakdown of glucose quickly without oxygen. Q2. Outline two benefits and two drawbacks of: (a) aerobic energy production – Can use glucose and fat as fuel; long-term energy supply; no fatiguing waste products. – Slow energy production; delay in reaching full working capacity (oxygen); cannot supply fast energy for high intensity; requires the use of glucose to break down fats. (b) anaerobic energy production – Fast energy for high intensity; no oxygen required; energy can be supplied when required/throughout a game; no waste products with the alactic/ATP-PC system. – Lactic acid build-up causes fatigue; short-term energy supply; slow to be replenished; inefficient use of nutrients/low energy yield. Q3. Explain how the three energy systems combine to ensure that our energy needs are met during physical activity. Refer to figure 4.1 in your answer. – At the start of activity the aerobic system is slow to provide enough energy due to a lack of oxygen in the muscles so the alactic system will provide most of the energy at the very beginning (10 seconds). – The lactic acid system will dominate the energy supply from around 10 seconds up until around 60–90 seconds when it will start to become depleted and the aerobic system gradually increases its contribution. – Beyond two minutes the aerobic system will supply the majority of energy as the supply of oxygen to the muscles has increased and the lactic acid build-up must be reduced. – In games the alactic system can be called on for short intense sprints throughout, provided adequate low-intensity recovery is taken. – The lactic acid system can also be called upon to increase its energy contribution for repeated longer sprints provided excess lactic acid levels have been recycled by the aerobic system in between. Q4. Sportspeople use all three of their energy systems while competing. The intensity and duration of the activity will determine which energy system provides the greatest contribution. For each energy system identify two activities that rely on this energy supply and justify your answer based on intensity and duration: (a) anaerobic alactic system (ATP-PC) – 100m sprinting requires very fast energy for a very short duration. – Throwing events (javelin, discus) require explosive energy production over a very short period. – Weightlifting requires maximum effort for a very short duration. (b) anaerobic lactic acid system – The 400m sprinter requires fast energy for 45–50 seconds. – Games players often have to make repeated sprints over a short period of time. – Rowers must work at a high intensity for several minutes. (c) aerobic energy system – Marathon runners must supply energy to the muscles for a long time at a steady intensity. – Games players must keep active in between high-intensity sprints to recover and keep up with play. The game can last in excess of 90 minutes requiring a significant amount of aerobic energy. – Road cyclists must complete stages up to and in excess of 200km requiring steady energy supply for several hours.

4.5 Impact on performance, practice and recovery

Introduction: Discuss how the need to train the predominant energy system will impact the structure of the session. – Compare the sprinter and the marathon runner (see Apply it). – Discuss the need for games players to train all three energy systems.

Explain how knowledge of the strengths and limitations of each energy system influence performance. Discuss the impact of intensity and energy system waste products on recovery post training. Outline the recovery process and ask students to identify strategies to improve recovery.

CASE STUDY QUESTION ANSWERS

Q1. Identify the strategies used to stimulate recovery from the previous day’s exertion. – Light aerobic exercise (stationary bikes) – Foam rolling the major muscle groups – Static and dynamic stretching exercises – Pool based mobility exercises – Cold water immersion. Q2. Suggest additional strategies that you would use with a team: (a) immediately after performance – Perform a cool-down of light aerobic exercise and stretching. – Consume a recovery drink containing high carbohydrate and protein. – Achieve full hydration (1kg body weight loss = 1.5 litres fluid). – Well balanced meal (complex carbohydrate and protein). – Massage, ice bath, NormaTec pulse recovery system. – Sleep. (b) in the days following the performance. – Massage/NormaTec – Stretching and mobility – Light training, especially aerobic exercise – Additional sleep – Consume regular complex carbohydrates and lean protein – Consume fruit and veg high in anti-oxidants – Maintain hydration.

PRACTICE QUESTION ANSWERS

Q1. Discuss how a coach should apply their knowledge of the energy systems to enhance training and performance. – The coach should structure training to stress the most important energy system(s). – The coach should allow adequate recovery during the session to maintain intensity, especially when targeting the anaerobic systems. – The coach must allow adequate recovery between training sessions with more recovery following high-intensity anaerobic training. – The coach should employ time-efficient training methods when the activity requires more than one energy system to be trained e.g. fartlek training.

PRACTICE QUESTION ANSWERS (continued)

– The coach should advise the performer on pacing during competition in order to maximise the use of each energy system without causing premature fatigue. – The coach should advise games players on the limits of the alactic (ATP-PC) system and the length of time required to replenish the creatine in the muscles. – An endurance coach should be aware of the aerobic and anaerobic thresholds in order to ensure correct pacing strategies. Q2. Explain why it takes longer to recover from high-intensity anaerobic training than from low-intensity aerobic training. – Build-up of fatiguing waste products. – Increased damage to muscle fibres from high-intensity effort. – Heart rate will remain elevated for up to 24 hours. – Muscle glycogen stores must be replenished with adequate carbohydrate intake. Q3. How would a performer know if full recovery had been achieved? – Heart rate, breathing rate and temperature have returned to normal. – Lactic acid levels have returned to normal (muscle fatigue/soreness reduced). – Fully hydrated. – Energy levels restored. Q4. Outline three ways performers can improve recovery. – Cool down – Ice bath – Diet (carbohydrate and protein intake) – Supplements – Sleep – Massage. Q5. Describe three benefits of performing a cool-down. – Maintaining elevated breathing rate and heart rate will increase oxygen levels in the muscles. – Gradually decreases temperature. – Recycles lactic acid as aerobic energy. – Reduces stiffness or DOMS. – Increases the removal of all waste products e.g. carbon dioxide. Q6. Outline the process of performing a cool-down. – Light aerobic exercise for at least five minutes. – Static stretching to lengthen the muscles.

TASK 4.7 ANSWER

Copy the table below and outline a training session that will enhance each energy system.

Characteristics ATP-PC system (anaerobic) Lactic acid system (anaerobic) Aerobic system (with O2)

Time/duration Very short fast intervals <6 seconds 10 x 40m sprint Short intervals <60 seconds 6 x 300m

Intensity Maximal effort; full sprint Hard >90% MHR 30 minutes – >2 hours of continuous training; 3–10 minute intervals or fartlek efforts Low to moderate intensity; 60%–85% MHR

Type of training Interval training; weight training; plyometric training Recovery Long: several minutes rest or light activity 1:20–1:50 Interval training; fartlek training

Long: lactic acid must be cleared >2 minutes 1:3–1:10 Continuous training; interval training; fartlek training

No recovery for continuous or fartlek; short recovery for intervals 3:1, 2:1, 1:1

END-OF-CHAPTER ASSIGNMENT – MARK SCHEME

(Can be used as summative assessment) Design an effective and specific dietary plan to meet the nutritional needs of an athlete in a named activity. (a) An outline of the main nutrients required based on the dietary requirements of the activity. – Carbohydrates such as pasta or bread for fast-release energy. Essential for highintensity anaerobic activities such as games, running events, gymnastic. – Fats, especially unsaturated fats such as olive oil, avocado, and fish provide enzymes for energy production and an almost limitless source of low-intensity aerobic energy. – Protein such as lean meat, beans and lentils provide amino acids for recovery from training and the growth and repair of tissues. – Vitamins are essential to maintain healthy body functions and the health of bones, ligaments and tendons, thus preventing injury. – Minerals are essential for maintenance of good health and performance. For example, iron is needed to create the red blood cells that carry oxygen to the muscles. (b) Outline a hydration strategy. Maintaining good hydration: – Drink little and often throughout the day. – Two litres of water per day. – Light coloured urine. Pre-event: – Drink small amounts regularly in the hours leading up to the activity. – Drink during training and competition e.g. hydration breaks/half-time. – Consume 300–500ml 15 minutes before the start of competition (pre-hydrate). During the event: – Only for events lasting longer than 60 minutes e.g. games, marathon. – Water, hypotonic or isotonic drinks. – 200ml every 15 to 20 minutes. Post-event: – Hydration status can be checked by weighing yourself pre and post event. – 1kg body weight reduction = 1.5 litres of fluid required. – Full hydration achieved when light coloured urine is passed regularly. – Electrolytes (salts/minerals) should be added to the drink to speed up hydration. – Hypertonic drinks can be used to speed up the replacement of glycogen stores. (c) Suggest strategies to support recovery and adaptation post training. – Perform a cool-down. – Consume a meal containing carbohydrate and protein within one hour of activity. – Consume a recovery drink containing electrolytes, carbohydrate and protein (hypertonic) immediately post exercise – Drink before, during and after training to maintain good hydration. – 8–9 hours of good quality sleep. – Massage to removes waste products and relax the muscles. – Ice baths to increase blood flow to the muscles. – Compression clothing to increase blood flow. – Cherry juice or beetroot juice (antioxidants). – NormaTec pulse recovery system.