chapter 8 anat + phys

• VO2 max = maximum volume of oxygen that can be taken up and used by the body per minute, an individual's VO2 max will determine endurance performance in sport
• lifestyle factors affecting VO2 max:

  1. smoking
  2. sedentary lifestyle
  3. poor diet
  4. poor fitness
• body composition affects VO2 max because a higher percentage of body fat decreases VO2 max
• training can affect VO2 max as it can be improved by 10-20% following a period of aerobic training (continuous, fartlek, aerobic interval)
• genetics can influence VO2 max as inherited factors of physiology limit possible improvement
• men generally have approx a 20% higher VO2 max than women
• as you age, VO2 max declines as body systems become less efficient
• VO2 max declines by 1% each year past the age of 25
• measuring energy expenditure is useful to give an indication of the intensity of the exercise and can identify levels of fitness, it can highlight dietary requirements to recover and fuel training, and provide feedback of effectiveness of training programme
• indirect calorimetry is a technique that provides an accurate estimate of energy expenditure through gas exchange, measures how much CO2 is produced and how much O2 is consumed at rest and at aerobic exercise
• calculating gas volumes in indirect calorimetry enables us to find out the main substrate being used (fat or carb) and the accuracy of this test is very reliable as it gives a precise calculation of VO2 and VO2 max
• lactate sampling = taking a blood sample and a hand held device analyses the blood and indicated how much lactate is present, accurate and objective measure of the level of lactate in the blood
• the higher the intensity of exercise at which the lactate threshold occurs, the fitter the athlete, and this allows the performer to select relevant training zones to get training effects
• regular lactate testing provides a comparison, if test results show a lower lactate level at the same intensity of exercise, the performer has increased time to exhaustion and recovery heart rate, therefore a higher lactate threshold
• sports science lab can produce much more valid and reliable results than the cooper run and the standardised fitness test using direct gas analysis
• direct gas analysis involve increasing intensities on a treadmill, cycle ergometer or rowing machines, volume and concentration in the expired air is measured and compared with percentage of O2 present in air to see how much has been taken in
• respiratory exchange ratio (RER) = ratio of carbon dioxide produced compares to oxygen consumed and is used as a measure of exercise intensity and fuel usage
• energy sources such as carbs, fats and proteins can all be oxidised to produce energy, and for a certain volume of oxygen, the energy released will depend on the energy source
• by calculating the RER, you can determine which energy source is being oxidised and whether the performer is working aerobically or anaerobically
• RER = CO2 expired per min (VCO2) / O2 consumed per min (VO2)
• RER value close to 1 = carbohydrates are being oxidised
• RER value of approx. 07. = fats are being oxidised
• RER value higher than 1 = anaerobic respiration so more CO2 is being made
• measuring the respiratory exchange ratio requires an athlete to be attached to a gas analyser while on a treadmill or cycle ergometer so that accurate readings can be taken on the amount of CO2 produced compared to oxygen consumed
• altitude training is usually done at 2500m+ above sea level where the partial pressure of oxygen is lower
• partial pressure of O2 drops as altitude increases, usually by up to 50% at 5000m, so there is a reduction in the diffusion gradient of oxygen between the air and the lungs and between the alveoli and blood, so not as much O2 diffuses into the blood so haemoglobin is not as saturated, so lower O2 carried
• at altitude, because less O2 is carried in the blood and delivered to the working muscles, there is a reduction in aerobic performance and VO2 max and a quicker onset of anaerobic respiration
• benefits of altitude training:

  1. increase number of RBCs
  2. increased concentration of haemoglobin
  3. increase in capillarisation and EPO so better enhanced O2 transport
  4. increase in lactate tolerance
• disadvantages of altitude training:

  1. difficult to acclimatise, loss of fitness and de training affects
  2. altitude sickness might occur
  3. benefits lost quickly when return to sea level and body can produce small amounts of EPO
  4. living far away can result in psychological problems e.g homesickness
• High Intensity Interval Training (HIIT) = form of training in which periods of work and interspersed with recovery periods, can be used for both aerobic and anaerobic training
• 4 main variables are used in interval training to ensure specificity:

  1. duration of the work interval
  2. intensity or speed of the work interval
  3. duration of the recovery interval
  4. number of work intervals and recovery intervals
• in HIIT, the work interval is anaerobic and the recovery is aerobic
• pushing your body to the max during the work interval in HIIT increases the amount of calories you burn as it takes longer to recover from each work session, so it improves fat burning potential, glucose metabolism and aerobic and anaerobic endurance
• variations of HIIT that involve:

  1. different number of high intensity work intervals and low intensity recovery
  2. different lengths of time for the work and recovery intervals
  3. different exercise intensity of the recovery (low or medium)
• plyometric training involves high intensity explosive activities such as hopping, bounding, depth jumping and med ball work to use fast twitch fibres
• plyo is based on the concept that muscles can generate more force if they have previously been stretched, so if an eccentric contraction occurs first followed by concentric, the force generated increases dramatically
• stretch shortening cycle in 3 phases:

  1. eccentric phase/pre loading phase, on landing the muscles stretch
  2. amortisation is time between eccentric and concentric, short time so energy is not lost
  3. concentric/muscle contraction uses up stored energy to increase force
• plyometrics to develop leg strength involve a line of benches, boxes, hurdles where the performer has to jump, hop and leap, recovery is walking back to start line
• plyometrics to develop arm strength involve throwing and catching a med ball, or press ups with claps, so that the triceps experience a quick stretch on landing or catching, and contraction when they do the up phase or throwing
• SAQ = Speed, Agility, Quickness