measurements of energy expenditure

• how is measuring energy expenditure useful

  • help to identify levels of fitness
  • highlight the dietary requirement needed for the performer to recover and replace energy thats been used
  • indicate the intensity of exercise that is being performed ( whether they are working anaerobically or aerobically )
  • provide feedback on effectiveness of a training programme
• describe method of indirect calorimetry

  • involves measuring how much carbon dioxide is produced and how much oxygen is consumed both at rest and during aerobic exercise
• evaluation of indirect calorimetry

  • reliable test that gives a precise calculation of V02 and V02 max
  • provides accurate estimate of energy expenditure through gas exchange
  • calculating gas volumes enables us to find out the main substrate being used ( fat or carbohydrate )
• describe method of lactate sampling

  • lactate sampling involves measuring the level of lactate in bloodstream
  • lactate levels measured in mmol/L
  • involves extraction of blood from vein using needle
  • its taken to calculate OBLA levels ( 4mmol/L ) and the resulting OBLA score compared to percentage of v02 max
• evaluation of lactate sampling

  • accurate measure used for elite perfomers in rowing, swimming and runningused by performers to
  • measure exercise intensity
  • identify fitness levels
  • allow performers to select relevant training zone
  • monitor improvements/ effectiveness of training
  • sprinters may use lactate sampling in training i.e test lactate at end of sprint race BUT results would probably have little impact on performance
  • marathon runner more likely to use lactate sampling to establish their OBLA point, this would dictate their optimal speed, raining would therefore be designed for just below OBLA
• method of respiratory exchange ratio RER

  • a gas analyser used to calculate the ratio or proportion of C02 released compared with oxygen used by body during exercise
  • it calculates energy expenditure and estimates the use of carbohydrate and fat used during exercise
  • RER = C02 expired per minute( VC02 ) / 02 consumed per minute ( V02 )
• evaluation of method of respiratory exchange ratio RER

  • tells if performer working aerobically or anaerobically and can be used to estimate which energy system used
  • RER close to 1 performer using carbohydrates
  • RER close to 0.7 performer using fats
  • RER value greater than 1 = anaerobic respiration ( more c02 being produced than oxygen consumed )
• method of V02 max tests

  •  - a progressive test to exhaustion carried out on treadmil or cardiovascular machine
  • test of aerobic endurance
  • used to calculate the maximal volume of 02 that can be consumed per minute ( ML/KG/MIN )
  • involves use of direct gas analysis ( measures concentration of 02 inspired & concentration of C02 expired )
  • V02 max can also be PREDICTED using multistage fitness test of cooper 12 min run
• V02 max evaluation

  • only reliable if carried out by a qualified technician in controlled environment
  • treadmill not valid for swimmers
  • v02 max genetically determined so limits training 10-20%
  • used by endurance athletes to monitor effectiveness of training
  • often used with lactate sampling to establish OBLA to design training jut below OBLA to improve aerobic capacity