Measurements Of Energy Expenditure

Question 1

Indirect calorimetry

Answer 1

• measures an estimate of energy expenditure through gas exchange
• measures how much Co2 is produced & how much o2 is consumed at both rest and during aerobic exercise
• calculation the gas volumes enables us to find out the main substrate being used (carbs / fats)
• accuracy of the test is reliable - gives precise calculation of the Vo2 max

Question 2

Lactate sampling

Answer 2

• take a tiny blood sample and hand held device will analyse the blood and indicates how much blood lactate is present
• accurate and objective
• means of measuring exercise intensity, the higher the intensity at which the lactate threshold occurs the fitter the athlete is.
• allows performer to select training zones - measured in HR or Power
• regular lactate testing: comparison to see improvement.
• if the results show lower lactate levels at the same intensity = increased peak power/speed, time to exhaustion, recovery HR and higher lactate threshold.

Question 3

Vo2 max test

Answer 3

• multi stage fitness test, Harvard step test and the cooper 12 minutes run - gives indications or predictions of the Vo2 max
• sports science laboratory = more valid and reliable results using direct gas analysis
  -> increasing intensities on treadmill, cycle ergometer or rowing machine
  -> air that is expired is calculated by computer software
  -> vo + conc of o2 is compared with the % of o2 that is in the atmospheric air = see how much o2 used in the task.

Question 4

Respiratory exchange ratio (RER)

Answer 4

RER = ratio of Co2 produced compared to o2 consumed + a measure of exercise intensity
- info on fuel usage during Ex, e.g. fats, carbs + protein (all can be oxidised to produce energy)
- for a certain vol of o2, energy released will depend on the energy source.
- calculating the RER determines which En source is being oxidised + whether the performer is working aerobically or anaerobically.

Procedure: athlete attached to gas analyser on treadmill or cycle ergometer

RER = Co2 expired per minute (VCo2) / o2 consumed per minute (Vo2)

Question 5

RER - what values of RER show that carbs and fats are the fuel source for that exercise

Answer 5

RER value close to 1 = using carbs
RER value approx 0.7 = fats
RER value greater than 1 = anaerobic respiration, more Co2 being produced than o2 consumed