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| What are the physiological tests? |
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This document outlines the general details of the physiological assessment for rowers, runners, cyclists and swimmers. The blood lactate and VO 2max test protocol will be different for each sport and training zones may be constructed differently. This document is for general information only and specific instructions will be given to clients to meet individual needs.
Fletcher Sport Science uses Heart Rate Variability (HRV) and specialised software (Suunto Training Manager and Firstbeat Technologies) to analyse tests results.
In some of the test and training zone descriptions the terminolgy - aerobic and anaerobic is used - these terms are used because they are in general use although it must be noted that they are disputed terms and not generally used by Fletcher Sport Science.
Training zones resulting from a test will be fully explained in terminology appropriate to the use of 'Training Effect' as the tool to monitor training and exercise performance.
Athlete preparatory guidelines and explanations
To ensure the accuracy of the tests, all athletes are asked to follow the guidelines:
1. DO NOT undertake ANY training for 24 hours prior to the test. Ensure that only light aerobic training is completed 48 hours prior to the test and avoid any heavy weight training.
2. Eat a normal meal (incorporating high carbohydrate) on the evening before the test. On the day of the test do not eat anything for 2 hours before test time. There will be sufficient time to consume a carbohydrate snack and fluids between tests.
3. Do not drink caffeine on the day of the test and ensure full hydration.
4. Bring appropriate clothing and footwear for undertaking the tests. There is a possibility that some blood may drip onto clothing so it is advisable not to wear anything of value.
5. If travelling a long distance, please try to arrive at least 30 minutes in advance to allow stretching and relaxation before testing.
6. Before testing can begin all athletes must complete an Informed Consent Form and Pre-Test Medical Questionnaire. A full explanation of each test will be given. Tests will not proceed if answers to the medical questionnaire are unacceptable (unless a Doctors certificate is produced).
7. Note: If any of the tests show other than a normal range of readings we will immediately recommend referral to a Doctor. We and the athlete both have the right to stop the tests at any stage.
If you have any questions regarding your preparation for the testing or the testing procedures, please contact me using email (eddie@fletchersportscience.co.uk) or telephone (01386 40050 or 07711 092733).
Physiological Assessment
1. Resting assessment of heart rate, blood pressure, haemoglobin and lactate as an indicator of cardiovascular health.
1.1 Heart rate gives an indication of the cardiovascular effort required to circulate blood and provide oxygen to maintain exercise intensity. Normal resting values are between 60-80 beats per minute but athletes often have lower resting heart rates and lower heart rates for any given exercise intensity. This is a result of the aerobic training adaptations that occur from regular exercise. These adaptations include an increased blood volume and an increased contractility of heart which together mean the heart has to beat fewer times in order to circulate a given volume of blood.
The normal heart rate response to increasing exercise intensity is a steady linear increase until a plateau (levelling off) at maximal levels.
1.2 The measurement of blood pressure gives a good indication of the health of the cardiovascular system. The top number or systolic BP is the pressure within the arteries when the heart is pumping. It can be variable as it is affected by anxiety, exercise, food and caffeine intake and rises during exercise. The bottom number or diastolic BP represents the pressure within the arteries in between each heart beat when the heart is not contracting and is relatively unaffected by anxiety and food etc. Blood pressure provides an assessment of the amount of force that the blood exerts on artery walls during contraction of the heart (systolic) and relaxation of the heart (diastolic).
Blood pressure is reported in millimetres of mercury (mm Hg) as systolic/diastolic (120/80mm Hg). The normal range for systolic BP is 120 –160mm Hg and for diastolic is 80 – 90mm Hg.
Poor diet, smoking and ageing all contribute to increases in blood pressure - fatty deposits on the inner artery wall build up. This deposit narrows the arteries and blood is therefore under greater pressure when passing through the arteries.
1.3 Haemoglobin is the component in the blood that transports oxygen from the lungs to the muscles. Too little iron in the diet can lead to a decrease in haemoglobin levels. People who have a low haemoglobin level and take part in regular strenuous exercise cannot provide the muscles with enough oxygen and so become tired easily.
Normal values in males are 14.0 - 18.0 grams per decilitre of blood (g.dl-1) and for women 12.0 - 16.0 grams per decilitre of blood (g.dl-1). A good iron intake can be maintained by eating meat (beef, kidney, liver), breakfast cereals, bread and vegetables (courgettes, lettuce, watercress).
1.4 Haematocrit is the percentage of blood volume made up of red blood cells. The range for females is 36%-48% and for males 40%-52%.
1.5 Blood lactate is a natural by product of one of the body energy systems. At rest and during gentle exercise blood lactate level remains relatively constant at around 0.5 – 1.5 mmol.l-1. This is because the lactate produced can be redirected to non-working muscles, the heart and the liver and recycled as an additional energy source. As exercise intensity increases and more blood is used to supply oxygen and remove waste products the body cannot recycle the lactate easily and lactate begins to accumulate in the blood.
Because blood lactate is an acid once it begins to accumulate it has a negative effect on the body by decreasing the normal pH levels and slows down energy production. The ultimate effect is that energy is produced at increasingly slower rates and performance reduces. Blood lactate also causes muscle cramps and nausea.
On the lactate – exercise intensity curve two specific thresholds are identified. The first is the lactate threshold (LT), which represents the exercise intensity where the lactate concentration begins to rise above resting levels. The second point is known generally as (AT) and this represents the exercise intensity where lactate production and accumulation will occur rapidly. Exercising below the lactate threshold will ensure that blood lactate does not accumulate and training will be aerobic. Above this point the body will fatigue quickly.
2. Lung function
2.1 Forced Vital Capacity (FVC) is the total amount of air in litres breathed out after completely filling the lungs.
2.2 Forced Expiratory Volume in one second (FEV1) is a measurement of how much air in litres forcibly expelled in one second. In order to assess if this represents normal lung function, FEV1 is expressed as a percentage of FVC (FEV1%).
2.3 Peak Flow Rate is the maximum velocity at which air in litres per minute can be expelled from the lungs. It is an important measure as it reflects airway resistance and respiratory muscle tone.
3. Inspiratory muscle strength
Research suggests that during exercise the inspiratory (breathing) muscles fatigue quickly limiting exercise performance. Breathing muscle strength is measured in centimetres of water (cm H20) commonly known as PImax. The use of a PowerBreathe device will improve the strength of the breathing muscles and improve performance. This is because normal respiratory muscle work compromises leg blood flow during exercise. By improving the strength of the breathing muscles the demand for blood by the respiratory muscles is reduced increasing the amount of cardiac output to the leg muscles leading to improved performance.
4. Body Composition
The body can be split into fat mass and fat free mass. Fat free mass (FFM) is comprised of bone, muscle and essential organs, and fat mass is comprised of fatty tissue only. Fat mass is referred to as metabolic dead weight. In the majority of athletic events fatty tissue does not contribute to an athletes’ performance – it often slows performance since the weight of the fatty tissue has to be carried/supported by the athlete. Athletes therefore have reduced fat mass compared to non-athletes.
Skinfold measurement provides an indication of subcutaneous fatty tissue. Whilst this is not the only way in which fat is deposited within the body it is the easiest to assess. By measuring skinfold thickness at a range of sites around the body it is possible to provide an index of the degree of fat tissue within the body. This value is recorded as a sum of skinfolds (mm) and this sum can be monitored throughout various stages of training to indicate increases or decreases in fat tissue. Percentage body fat values are not reported due to the inaccuracies of using prediction equations – typical errors are ? 4% and therefore are unable to detect small but important changes that occur with training.
Hydration is important to ensure optimal training and racing performance. Water levels are measured and optimal ranges given.
6. Cholesterol
Cholesterol is essential for human life but if the concentration becomes too high the risk of chronic heart disease (CHD) may be increased significantly. HDL-Cholesterol is ‘good’ and LDL-Cholesterol is ‘bad’. High HDL concentrations lower the risk of CHD whilst high concentrations of LDL significantly increase the risk. The commonly adopted risk factor cut-off point for total cholesterol concentration is 5.2 mmol l_1 (200 mg dl-1) although optimal levels are lower. Diet, weight and exercise all affect cholesterol levels.
7. Diabetes
Diabetes mellitus is a condition in which the amount of glucose (sugar) in the blood is too high because the body is unable to use it properly. Normally as the glucose level in the blood increases the pancreas releases a hormone called insulin which regulates the glucose level to prevent it becoming too high or too low. The risk of diabetes is greater if diet is incorrect, through overweight and lack of exercise. Diabetes mellitus is defined by hyperglycaemia with a fasting normal glucose level of 6.1 mmol l-1(110mg dl-1) and suspected diabetes mellitus with a reading in excess of 7.00 mmol l-1 (126mg dl-1).
8. The Blood Lactate Profile Test
The body constantly produces lactate. At rest and in light exercise the level of lactate that is produced is small enough for the body to effectively remove it from the working muscles without it becoming a problem. With increasing exercise intensity, lactate production increases and reaches levels that become a problem due to the combination of lactate and fatigue. By assessing blood lactate at a range of exercise intensities a blood lactate curve can be plotted from which lactate thresholds can be determined which are important in monitoring and building a balanced fitness level.
Protocol
- Long, gentle warm-up.
- Sport specific stages of increasing intensity.
- Intensity of each stage is determined from current sport specific performance.
- At the end of each stage a small blood sample will be taken from the ear lobe/finger in order to measure blood lactate levels.
- Heart rate is monitored continuously throughout the test and recorded at the end of each stage.
- Long gentle warm down.
- The test can be stopped by the athlete at any time.
9. VO 2max Test
Maximal aerobic capacity ( VO 2max) provides a measure of aerobic power. It reflects an individuals’ ability to take in, transport and utilise oxygen at the active muscle level. The higher an individual’s aerobic capacity the greater their endurance ability. Maximal aerobic power is influenced by a number of factors including muscle mass, age, and gender and training status. In untrained individuals, VO 2max can increase by as much as 20%, however in already trained individuals changes are much lower in the region of 2-3%.
Research has demonstrated maximal aerobic power is a limiting factor in many sports performances and therefore a good determinant of success.
Protocol
- Long gentle warm-up.
- Sport specific stages of increasing intensity until voluntary exhaustion or inability to maintain required exercise intensity.
- Intensity of each stage is determined from current sport specific performance.
- Heart rate is monitored continuously throughout the test and recorded at the end of each stage.
- Oxygen consumption (VO 2max) will be collected continuously throughout the test and recorded at the end of each stage.
- On completion of the test (voluntary exhaustion) a long gentle warm down.
- The test can be stopped by the athlete at any time.
10. Training zones
Lactate threshold is highly trainable even in already trained athletes. The most successful endurance athletes have a lactate threshold at a very high percentage of their VO 2max and by training at or just below the lactate threshold further aerobic adaptations may occur that increase the exercise intensity at the lactate threshold.
Some sports require an athlete to work at a high percentage of their maximal capacity. Therefore some training must be done close to anerobic threshold. This will promote the use of the anaerobic energy systems.
Depending on the specific requirements of individual sports it is important that training balances aerobic efforts (to increase the intensity of exercise completed without the accumulation of lactate) and high intensity anaerobic efforts.
Based upon heart rate and lactate at the thresholds, six zones of exercise intensity can generally be identified with a specific heart rate range applying to each zone. U3 represents recovery and long endurance exercise carried out below LT. U2 and U1 represent exercise performed between LT and AT, with U2 representing the zone of LT. AT constitutes work performed at anaerobic threshold, and T (transport) comprises anaerobic efforts above AT. The sixth zone is not based on the lactate but represents exercise at race pace or above.
Athletes should attempt to keep their heart rate within these zones as much as possible during training since this will ensure the optimal training adaptations occur. It is important that the mean heart rate for any training activity is within the target zone identified.
11. Individual Results and Training Zones
Individual results will be communicated following the physiological assessment for incorporation into training programmes. |
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Date : 23 April 2005 |
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