Date post: | 31-Mar-2015 |
Category: |
Documents |
Upload: | katelyn-abbot |
View: | 228 times |
Download: | 0 times |
AEROBIC CAPACITY
What is Oxygen Uptake?
What is VO2 Max?
OXYGEN UPTAKE - VO2
amount of oxygen consumed per unit of time (usually 1 minute)
expressed as VO2
mean value at rest = 0.2 to 0.3 l min-1
VO2 increases proportionally to work intensity
up to a maximum value - called VO2max
DRAW A GRAPH TO ILLUSTARTE THE
DIFFERENCE BETWEEN A TRAINED AND UNTRAINED ATHLETE IN RELATION TO
THEIR VO2 MAX
Trained Athlete
Untrained Athlete
AEROBIC CAPACITYthe ability to do physical work which is
dependant on the aerobic mechanism of energy supply
STEADY STATE• the demands of the body for oxygen is
balanced exactly by oxygen uptake
FACTORS AFFECTING VO2 MAX• Availability of O2 in the tissue
– Is haemoglobin saturated with oxygen at muscle tissue
– Varies individual to individual– Myoglobin in muscle cells is fully saturated
with O2 (has sufficient recovery time elapsed?)
• reduction in VO2max will cause decline in aerobic performance
• Age – reduction by 10% per decade• Aerobic training can improve by 10%• Women tend to have greater reductions in VO2
max
DRAW A GRAPH TO ILLUSTARTE VO2MAX AGAINST AGE FOR TRAINED &
UNTRAINED MALES
ONSET OF BLOOD LACTATE ACCUMILATION
OBLAas work intensity increases lactic acid starts to
accumulate above resting valuesat a certain point this produces muscle fatigue and
painthe resultant low pH inhibits enzyme action and cross
bridge formationhence muscle action is inhibitedphysical performance deterioratesthis point governs the lactic aerobic thresholdtrained athletes begin OBLA at higher work intensities and higher values of VO2max than untrained people
FOOD FUEL USAGEFOOD FUEL USAGEthis depends on :
EXERCISE INTENSITYEXERCISE DURATION
SOURCES OF FUELSmain source of CHO for muscular energy during exercise is glucosederived from stored muscle and liver glycogenlack of CHO fuel is the limiting factor for aerobic endurance performance
main source of fat for muscular energy during exercise is free fatty acids (FFA) derived from triglycerides stored as adipose tissue under the skin and in muscle tissue
FOOD FUEL USAGE FOR AEROBIC ACTIVITY
ADAPTATIONS TO AEROBIC CAPACITYcardiovascular system becomes more
efficientmore haemoglobin is created and is available
in blood for oxygen transportpulmonary systems become more efficientlung volumes increase slightly, greater
volumes of air can be breathed per breathImproved oxygen recoveryHence reduction in DOMSMore myoglobin is created in muscle cellsMore and bigger mitochondria in muscle cells