VO2 max and OBLA

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  • VO2 max
    • Maximum oxygen consumption attainable during maximal work
    • Affecting Factors:
      • Age
      • Gender
      • Genetics
      • Training Intensity
      • Amount of haemoglobin in the blood
      • Amount of capillaries around the lungs and the working muscles
    • Maximum volume of oxygen that can be consumed during maximal workout
    • For training aimed at improving a performer's VO2 max using the aerobic system:
      • The work - relief ratio is normally longer in duration and intensity, just below the anaerobic threshold.
      • The relief ratio is typically shorter    (ratio 1:1), which helps reduce the OBLA and delay muscle fatigue and therefore prolong the aerobic system adaptations
    • VO2 = Volume of oxygen consumeed
    • APPLY IT: some elite marathon runners and cross country skiers can perform at up to 90% VO2 max without significant lactic acid production (OBLA)
        • This means the point at which the muscle can no longer get rid of the lactic acid and it begins to pool in the blood
        • Normal amount of lactate in the blood = 1ml/kg
          • OBLA occurs at = 4ml/kg
            • If the intensity of the activity increases, the performer will have to switch from using aerobic capability to anaerobic which results in increased lactate build up
        • Once the blood contains four times as much lactic acidd as normal, it can NO LONGER OPERATE THE ENERGY SYSTEMS EFFECTIVELY and the body begins to slow and eventually fail
        • The affects of OBLA:
          • Stops oxygen being collected by the haemoglobin
          • Causes the pH of the blood to rise causing pain in the working muscle
          • Also decreases the amount of oxygen that can be used for phosphorylation
          • Will eventually lead to the muscle failing - YOU WILL COLLAPSE!
      • Average person reaches OBLA at 40% of VO2 max - meaning that the average person can only work at less than half their maximum ability before fatigue sets in
    • The amount of oxygen the body can take in and use in one minute
      • Why? - Gives an accurate idea of how well a person's body can perform over a long period of time OR the intensity in which they will be able to perform
    • Training effects
      • Increased haemoglobin
      • Increased OBLA
        • Factors affecting OBLA
          • Muscle fibre type being used
          • Training adaptations to exercise
          • Intensity of exercise
      • Reduced body fat (therefore less oxygen being used for the energy systems
      • Increased cardiac output and stroke volume


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