PRELIMINARY HSC PDHPE CQ2 – What is the relationship between physical fitness, training and movement efficiency?

What is the relationship between physical fitness, training and movement efficiency? Students learn about: health-related components of physical fitness cardiorespiratory endurance muscular strength muscular endurance flexibility body composition Students learn to: analyse the relationship between physical fitness and movement efficiency. Students should consider the question ‘to what degree is fitness a predictor of performance?’ skill-related components of physical fitness power speed agility coordination balance reaction time   measure and analyse a range of both health-related and skill-related components of physical fitness think critically about the purpose and benefits of testing physical fitness aerobic and anaerobic training FITT principle design an aerobic training session based on the FITT principle compare the relative importance of aerobic and anaerobic training for different sports, eg gymnastics versus soccer immediate physiological responses to training heart rate ventilation rate stroke volume cardiac output lactate levels. examine the reasons for the changing patterns of respiration and heart rate during and after submaximal physical activity.

Immediate physiological responses to training When an individual exercises, many physiological changes occur within the person’s body. These range from a need for more oxygen in working muscles to an increase in body temperature. With aerobic training, the following immediate physiological responses are observable and measurable: heart rate (HR)—as exercise intensity increases, so too does the rate at which the heart beats ventilation rate—at the beginning of exercise, there is an immediate increase in ventilation— both inspiration (breathing in) and expiration (breathing out)—followed by a continuing gradual rise in the depth and rate of breathing stroke volume (SV)—the amount of blood ejected with each contraction of the heart also increases cardiac output (Q)—the volume of blood that is pumped out of the heart per minute also increases during exercise, thus forcing more blood out of the heart (Q = HR x SV) lactate levels—lactic acid consists of a solution of lactate ions and hydrogen ions in water; with intensifying aerobic exercise there is an increase in the level of hydrogen and lactate ions in the blood, but this later evens out with lactate being removed as fast as it is made.

Immediate physiological responses to training Cardiac output and ventilation increase to ensure that working tissues are supplied with oxygen and nutrients, and to remove wastes. To assist in these processes, the body directs blood away from non-working areas to working areas. Term What is it? (Definition) Immediate change Heart rate Number of contraction (beats) that the heart makes in a set time e.g. 60 beats per minute Increases Ventilation rate Number of inhalations or breaths made in a set time e.g. 60 breaths per minute Stroke volume The amount of blood pumped in any one contraction (or beat) of the heart Cardiac output The rate of blood pumped by the heart in a period of time e.g. 4.8 litres per minute   Lactate levels Lactic acid is a by-product made by muscles when there is insufficient oxygen available to produce aerobic energy. Lactic acid causes the burning sensation in hard working muscles Increase if activity is anaerobic or higher intensity

Immediate physiological responses to training The rate of blood pumped by the heart (cardiac output) is a product of the rate at which the heart beats (heart rate) and the volume of blood that the heart pumps with each beat (stroke volume). In a resting heart, the cardiac output is about 5 litres a minute (0.07 L × 70 beats/min = 4.9 L/min). Cardiac output = heart rate x stroke volume Q = HR x SV

Immediate physiological responses to training – heart rate Resting heart rate (HR) varies among individuals depending on their fitness level— an elite endurance athlete may have a resting heart rate as low as 28 bpm, while an unfit sedentary person’s can be as high as 100 bpm. On average, an adult’s resting heart rate will be 70–75 bpm. Just before we begin to train, our heart rate will rise in anticipation so our true ‘resting’ heart rate should be taken first thing in the morning. During maximal exercise, there is a linear increase in heart rate corresponding to the increase in exercise demands, until you reach your maximum heart rate. This pattern occurs for both trained and untrained participants. However, at any given submaximal workload, the untrained person will have the higher heart rate. The trained participant will have a sharp increase in heart rate at the beginning of exercise, which will then plateau when they reach steady state during submaximal exercise. During prolonged exercise at a constant workload, the heart rate will shift from the steady state upwards due to cardiovascular drift. When undertaking resistance training, there is an increase in heart rate the more repetitions that are performed. The cardiorespiratory fitness level of a person will determine how quickly the heart rate returns to resting levels after exercise—the fitter you are, the quicker you recover. Initially there is a large drop for both trained and untrained individuals.

Immediate physiological responses to training – heart rate Activity/task Compare the following heart rate graphs for a 20-year-old athlete during two different training sessions. a Calculate their maximum heart rate, 75 % max HR and 90 % max HR. b Estimate the amount of training time they would have spent below 75 % max HR, between 75–90 % max HR and above 90 % max HR for each training session. c What does monitoring the athlete’s heart rate during the two sessions tell the coach about the intensity of these two training sessions?

Immediate physiological responses to training – heart rate

Immediate physiological responses to training – ventilation rate Ventilation rate refers to the movement of air into (inspiration) and out of (expiration) the lungs and is more commonly known as breathing. At rest, the average person will perform 12 breaths of approximately 500 millilitres each minute resulting in a ventilation rate of 6 litres/minute. Similar to heart rate, there is an anticipatory rise in ventilation rate as we begin exercising. Once exercise actually commences, there is a second rise in ventilation rate as the rate and depth of breathing increases. This increased ventilation corresponds with increased oxygen consumption and carbon dioxide production. It has been suggested that, during maximal exercise, the main influence on minute ventilation is the need to remove carbon dioxide rather than the need for oxygen. For this reason, ventilation rate does not limit a person’s aerobic capacity. Maximal minute ventilation rates can reach 130 and 170 litres/ minute for untrained and trained participants. Figure 5.24 illustrates the ventilatory response to light, moderate and heavy exercise. As can be seen in the graph, once exercise ceases there is an initial rapid decline followed by a gradual return to resting ventilation rates.

Immediate physiological responses to training – ventilation rate

Immediate physiological responses to training – stroke volume Stroke volume (SV) refers to the amount of blood pumped from the heart (left ventricle) per beat. Resting stroke volume values are approximately 50–60 millilitres for untrained participants and 80– 110 millilitres for trained participants. These values then increase during exercise to approximately 100–120 millilitres for untrained, and up to 200 millilitres for trained participants. It is thought that maximal stroke volume occurs at a work intensity corresponding to 40–60 per cent maximal and then plateaus as exercise intensity increases. The large difference in maximal stroke volume amounts between trained and untrained individuals is a major contributing factor to aerobic endurance. Increased stroke volume is due to the left ventricle holding more blood and a stronger contraction, then emptying more blood per beat. There is virtually no change from resting levels when performing resistance training. Women will tend to have a slightly lower stroke volume than men.

Immediate physiological responses to training – cardiac output Cardiac output (Q) refers to the amount of blood pumped from the left ventricle each minute. It can be calculated as: Q (L/min) = SV (mL) x HR (bpm) Cardiac output under resting conditions is similar for trained and untrained individuals, and is approximately 5–6 litres. There is a sharp increase in cardiac output as exercise commences, and this continues to increase as workload increases in order to meet the exercising muscles’ demands for more oxygen. Interestingly, cardiac output is similar for trained and untrained individuals at submaximal workloads. This is because the trained person will have a higher stroke volume and lower heart rate compared to the untrained individual, who will have the higher heart rate and lower stroke volume.

Immediate physiological responses to training – cardiac output For example: An untrained participant at 50 per cent maximal effort has a heart rate of 140 and a stroke volume of 100 millilitres. Their cardiac output is 140 x 100 = 14 L/min. A trained participant at 50 per cent maximal effort has a heart rate of 100 and a stroke volume of 140 millilitres. Their cardiac output is 100 x 140 = 14 L/min. The main difference between trained and untrained individuals is their maximal cardiac output. Trained athletes have recorded maximal cardiac outputs of 40 litres compared to untrained individuals who average 20 litres. Women will tend to have a slightly lower cardiac output than men have.

Immediate physiological responses to training – cardiac output The figure above illustrates the distribution of cardiac output at rest and during maximal exercise. We see in this example that cardiac output rose from 5.8 litres at rest to 25 litres during maximal exercise. The main change has been the redistribution of blood from the various body organs to the skeletal muscles, which now receive 88% of cardiac output (compared to 21% at rest) in an attempt to meet the muscles’ demand for oxygen. As a thermoregulatory measure (in other words, to keep the body cool), there is an increase in blood flow to the skin during maximal exercise.

Immediate physiological responses to training – lactate levels Lactate is produced by the breakdown of carbohydrates and is cleared from the body by the muscles. Under resting conditions, its clearance rate is in balance, resulting in constant levels of 1–2 mmol/L. During exercise, lactate levels will increase as the body produces lactic acid to create energy for the muscles. The amount will vary depending on the intensity of the exercise. High-intensity exercise will create higher lactate levels. As depicted in the figure above, during low intensity exercise the lactate levels remain fairly stable. However, as intensity increases and the body has a greater demand for energy, the production of lactate exceeds the rate at which it can be removed. Consequently, we get an exponential rise in blood lactate accumulation. It is thought that this is due to a reliance on anaerobic glycolysis, less oxygen being available in the tissues, the recruitment of fast twitch-fibres and the reduced removal of lactate.

Immediate physiological responses to training – lactate levels Three elements of the lactate curve provide important information for the coach. These are the intensity or speed of exercise that corresponds to lactate threshold, the maximum amount of lactate that can be produced and the slope of the curve. Lactate threshold is the speed or intensity of exercise that results in a sustained increase in lactate concentration above resting levels. Therefore, below this workload is where someone can exercise at a steady state. For untrained people this generally corresponds to 50–60 per cent VO2 max, whereas in trained endurance athletes this can be at 75–85 per cent VO2 max. The maximum amount of lactate that can be produced is a reflection of a person’s anaerobic conditioning, with 400-metre runners recording maximum lactate levels of >20 mmol/L. The slope of the curve for trained athletes is shifted to the right.

Immediate physiological responses to training – lactate levels Once maximal exercise ceases, lactate levels will begin to return to resting levels. Passive recovery results in 50 per cent of the lactate removed within 15–20 minutes, and resting levels restored after 30–60 minutes. However, optimal levels of lactate removal occur with an active recovery at an intensity below a person’s lactate threshold. Cool- downs at 30–45 per cent intensity (max VO2) for untrained exercisers and between 50–65 per cent intensity for trained athletes can return lactate concentrations to resting levels within 20 minutes.

Immediate physiological responses to training – lactate levels   At rest Maximal exercise Male, age 30 untrained trained Heart rate (bpm) 72 40 190 Stroke volume (mL/beat) 50–70 80–110 100–120 Up to 200 Cardiac output (L/min) 5–6 20 Ventilation rate (L/min) 6 130 170 Lactate levels (mmol/L) 1–2 10

Immediate physiological responses to training – questions 1 – What are the reasons for the changing patterns of respiration and heart rate during and after submaximal physical activity?

Immediate physiological responses to training – questions 2 – The following graph shows the lactate response during a 1500-metre race. a Identify the stage of the race that corresponds with the runner’s anaerobic threshold. b Explain why there was an increase in lactate levels towards the end of the race. c Discuss the type of recovery strategy you would recommend to assist the removal of lactic acid. d Describe the heart-rate response during the race.

Immediate physiological responses to training – questions 2 The following components have been identified as being important for tennis performance. Outline one test for each component that you would recommend be included in a tennis player’s fitness-testing schedule. a aerobic fitness b agility c flexibility d power e coordination. (5 marks)

Immediate physiological responses to training – questions 3 Using the FITT principle, design a one-week training program for a person in their late twenties, who has not done any exercise since school. FITT principle Aerobic training Frequency 2-4 aerobic sessions per week, involving running and cycing Intensity Approximately 75% of MHR = 150 bpm to work them out, but not over exert them Time 1 x 20 mins, 2x 25 mins Type Cycling—continuous and running, continuous or fartlek – to give some recovery.

Immediate physiological responses to training Summary The eleven components of fitness are health related (necessary for the efficient functioning of the body) and skill-related (of importance to movement performance). There are five health-related components of fitness: cardiorespiratory endurance, muscular strength, muscular endurance, flexibility and body composition. There are six skill-related components of fitness: power, speed, agility, coordination, balance and reaction time. There is a clear relationship between physical fitness, health and performance. The FITT principle can be applied to any exercise program based on improving aerobic fitness. It is based on the frequency, intensity, time and type of exercise. The body demonstrates five immediate physiological responses to exercise. These are changes to heart rate, ventilation rate, stroke volume, cardiac output and lactate levels. These changes occur to allow the working muscles to receive an increased supply of oxygen and nutrients and to remove wastes, such as carbon dioxide and water.