Measurements of energy expenditure

• measurements of energy expenditure

  This identifies levels of fitness and intensity of exercise

  highlights dietary needed to recover and replace energy used

  give feedback on the effectiveness of training
• indirect calorimetry

  this estimate energy expenditure through gas exchange

  it measures carbon dioxide produced and oxygen consumed at rest and during aerobic exercise

  it finds the main substrate used (for example fat or carbs) and calculates VO2 and VO2 max therefore is reliable
• lactate sampling

  the blood sample is taken and a device measures how much lactate is present

  is a accurate and objective measure of blood lactate

  the higher the intensity at which the lactate threshold occurs the fitter the athlete therefore this indicates fitness levels and select relevant training zones

  regular tests are completed to compare improvement and see if lower lactate levels are occurring at the same intensity therefore performer has increased their speed / power / time to exhaustion / improved recovery time / increased threshold
• VO2 Max test

  this is the bleep test= 20m progressive shuttle run to a beep until complete exhaustion, the level reached is compared to a standard results table

  this is a valid and reliable test if done in a lab: Direct gas analysis measures the concentration of oxygen inspired and the concentration of carbon dioxide expired

  how it works:

  high intensity on a treadmill until exhaustion, expired is calculated on the computer, volume and concentration of oxygen in the atmosphere is compared to the computer data, we can see how much oxygen is used during the task
• respiratory exchange ratio

  the ratio of carbon dioxide produced compared to oxygen consumed and is used as a measure of exercise intensity

  a value between 0.7 and 1 indicates a mixture of fats and carbohydrates as the energy source

  a value greater than 1 indicates anaerobic respiration due to more carbon dioxide being produced than oxygen consumed

  volume less than 1 indicates aerobic respiration due to less carbon dioxide being produced and oxygen consumed

  this is measured with the athlete attached to a gas analyser while on a treadmill or cycle
• What is direct gas analysis ?

  Measures the concentration of oxygen that is inspired and the concentration of carbon dioxide expired.
• What is a cycle ergometer?

  A stationary bike that measures how much work is being performed
• RER ratios 


  RER value close to 1 = performer using carbohydrates

  RER value approx. 0.7 = performer using fats

  RER value greater than 1 = anaerobic respiration, so more CO2 produced than being consumed