In McArdle, Katch and Katch (1994) it is suggested that three important factors determine endurance (aerobic) performance:
While exercising aerobically a person operates at a certain VO2. VO2 is the volume of oxygen being metabolized by the body at any one time. VO2 max therefore is the maximum amount of oxygen that can be metabolized by the body. This figure is a useful measure of aerobic fitness, and is represented in milliliters of oxygen per minute (mls/min) or milliliters per kilogram per minute (ml/kg/min). It reflects well, an individual's ability to aerobically resynthesize ATP (the molecule which supplies the body's cells with energy). In short, VO2 increases as exercise intensity increases. The harder a person exercises, the higher their volume of oxygen utilized (VO2).  Anaerobic Threshold and Lactate Threshold As the intensity of exercise increases and oxygen supply to the working muscles becomes inadequate, lactic acid is produced. This is due to the muscles greater reliance on energy being produce anaerobically (without oxygen). Anaerobic Threshold (AT) also described as OBLA (Onset of Blood Lactate Accumulation) is the point at which blood lactate is being produced faster than it can be remove. Lactic acid accumulation in the muscles causes discomfort and at increasing levels will eventually result in the activity being reduced or stopped. AT is a good predictor of endurance performance, often offering a better indicator than VO2max. In a study that compared race-walking velocity with AT, performance was predicted to within 0.6% of the actual time! AT in healthy untrained subjects occurs around 55% of VO2 max (69% of max heart rate). World class endurance athletes can have an AT of 85-90% of their VO2 max (91-94% max heart rate)! The other performance measure of Lactic Acid production is the Lactate Threshold (LT). This is the first workload producing a sustained increase in Lactate above resting values, and can be used in aerobic training zone calculations.  Economy of effort describes how much energy is being wasted or directed towards the activity. For example two physiologically identical athletes may run at different speeds, while running at the same heart rate. This is because the faster athlete has a more economical running style than the slower athlete does. This principal can be applied to all sports, for example smooth pedaling in cycling, fluid swimming technique for swimmers and so on. In conclusion, each of these areas can be tested and improved to enhance aerobic performance. When combined with strength and power testing, as well as strength and power training, will lead to a well balanced athlete. |
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The Science |
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