Chapter 5 in Text p. 117 (Malpeli et al, 2008) Delivery of Oxygen Chapter 5 in Text p. 117 (Malpeli et al, 2008)

Oxygen Deficit The period during exercise where the O 2 SUPPLIED to the MUSCLE is BELOW that required to produce all of the ATP aerobically. Examples: At start of exercise. Periods during aerobic exercise where intensity exceeds 85%, Eg: riding up a hill or in a big gear, surging away from an opponent. The lactic acid system will produce the extra ATP required (aerobic still dominant) The size of the oxygen deficit is determined by the intensity of the activity. Consider light vs heavy exercise

Steady State STEADY STATE: The point during exercise when oxygen supply to muscle equals oxygen requirements (to produce ATP aerobically). Indicated by a plateau in hr, Q, SV and VO2 Dominant energy system: aerobic O2 supply = O2 consumption Endurance athletes with a higher LIP will be able to steady state at a higher intensity, delaying use of lactic acid system and accum. of H+, ADP + Pi

Oxygen Deficit

Heart Rate and Intensity

Oxygen Debt When there is insufficient oxygen delivered to, and taken up by the muscle, the anaerobic energy systems will supply the bulk of ATP.

OXYGEN DEBT: The amount of exercise consumed after exercise (during recovery) that is over the level consumed during rest. The size of the O2 Debt is dependant on the size of the O2 Deficit and the type / length of recovery used. The following occurs during EPOC: Resynthesise ATP and PCr Resyntheisie lactate to glycogen (cori cycle) Oxidise lactate Restore oxygen to myoglobin See Fig. 5.7 on p.123.

Heart Rate and Oxygen consumption When exercising; Our heart rate increases to meet the oxygen demands for the working muscles. The relationship between HR and oxygen consumption is linear. Trained athletes are able to utilise their oxygen uptake more efficiently than non trained people. Trained athletes VO2 will be lower at submax intensity and higher at max intensities. See fig 5.3 p.119

Oxygen debt

Oxygen Deficit and Debt During Light-Moderate and Heavy Exercise

What is EPOC? Another term used for the recovery oxygen consumption is Excess Post-exercise Oxygen Consumption EPOC)

The difference between Oxygen Debt and Oxygen Deficit Oxygen deficit – is the process of getting into debt Oxygen debt – how much oxygen needs to be repaid.

Test Yourself Quiz bt.htm

References McArdle, William D., Frank I. Katch, and Victor L. Katch Essentials of Exercise Physiology 2 nd ed. Image Collection. Lippincott Williams & Wilkins. Malpeli, R., Horton, M., Davey, G., & Telford, A. (2008). Nelson Physical Education VCE Units 3 & 4 (4 th ed). South Melbourne; Cengage. Website: en_debt.jpg Accessed on October 18., 2010.

Oxygen Uptake during Recovery Light exercise rapidly attains steady-rate and small oxygen deficit. Moderate to heavy takes longer to reach steady-rate & oxygen deficit considerably larger.