Aerobic power is also commonly called cardio-respiratory endurance, circulo-respiratory endurance, aerobic endurance, aerobic capacity and aerobic fitness. When people talk about heart,-lung fitness, general endurance, stamina or cardiovascular endurance, they are talking about the same thing - aerobic power. This is the ability of the circulatory and respiratory systems, the heart, lungs and blood vessels to deliver oxygen and nutrients to the tissues of the body and to remove waste products such as carbon dioxide, making energy available to the working muscles.
Aerobic power is most evident at rest; during sustained activity involving the whole body, such as running, swimming cycling long distances; and during recovery. It is the most essential physical fitness component, evident in everyday activities and in most team sports. Most of the benefits attributable to improved physical fitness are due to increased aerobic power.
Aerobic power is developed primarily through the use of continuous and interval training running. Continuous training improves oxygen uptake (V02max) and interval training improves tolerance of lactic acid, raises the anaerobic threshold and improves the efficiency of the heart as a muscular pump.
Factors Influencing Aerobic Power
Many factors influence aerobic power (VO2 max). The most important include heredity, training state, gender and body composition.
Heredity: Early studies were conducted on 15 pairs of identical twins (same heredity because they came from the same fertilised egg) and 15 pairs of fraternal twins (did not differ from ordinary siblings because they result from separate fertilisation of two eggs) raised in the same city by parents with similar socioeconomic backgrounds. The researchers concluded that heredity alone accounted for up to 93% of the observed differences in VO2max. Subsequent investigations of larger groups of brothers, fraternal twins, and identical twins indicate a much smaller effect of inherited factors on aerobic power and endurance performance.
Training State: Maximal oxygen uptake must be evaluated relative to the person's state of training at the time of measurement. Aerobic power with training improves between 6%-20%, although increases have been reported as high as 50% above pre-training levels. The largest VO2max improvement occurs among the most sedentary individuals.
Gender: VO2 max for women typically averages 15%-30% below values for men. Even among trained athletes, the disparity ranges between 10%-20%. The apparent gender difference in VO2max has been attributed to difference in body composition and the blood's hemoglobin concentration. Untrained young adult women posses about 25% body fat, the corresponding value for men averages 15%. Trained athletes have a lower body fat percentage, yet trained women still posses a significantly more body fat than their male counterparts. Consequently, males generate more total aerobic energy simply because they posses a relatively large muscle mass and less fat than females.
(Malpeli, Horton, Davey,Telford, 2006).
TESTING AEROBIC POWER (VO2max)
There are a number of tests that could be performed in order to test an individuals aerobic power as well as their VO2max, which are primarily the same thing.
Accurately measuring VO2 max involves a physical effort sufficient in duration and intensity to fully tax the aerobic energy system. In general clinical and athletic testing, this usually involves a graded exercise test (either on a treadmill or on a cycle ergometer) in which exercise intensity is progressively increased while measuring: ventilation and
oxygen and carbon dioxide concentration of the inhaled and exhaled air. VO2 max is reached when oxygen consumption remains at a steady state despite an increase in workload.
Beep Test: The test involves running continuously between two points that are 20 m apart from side to side. The runs are synchronised with a pre-recorded audio tape or CD or laptop software, which plays beeps at set intervals. As the test proceeds, the interval between each successive beep decreases, forcing the athletes to increase their speed over the course of the test until it is impossible to keep in sync with the recording (or, on extremely rare occasions, until the athlete completes the test). Many people who test people using the multi-stage fitness test allow one level to beep before the person makes the line, but if the person being tested does not make the next interval, the most recent level they completed is their final score. The recording is typically structured into 21 'levels', each lasting around 62 s. Usually, the interval of beeps is calculated as requiring a speed at the start of 8.5 km/h, increasing by 0.5 km/h with each level thereafter. The progression from one level to the next is signalled by 3 quick beeps. The highest level attained before failing to keep up is recorded as the score for that test.