Aerobic power directly influences the level of speed that the athlete is capable of maintaining over time. There are two major determinants of aerobic power:
V02
The maximum ventilatory capacity of the athlete or the athlete’s maximum ability to intake, absorb and utilize oxygen. It measures cardiovascular endurance or stamina. The mV02 is a weight sensitive variable (in ml/kg/minute) that reflects performance capability in endurance sports.
The following diagrams graphically illustrate the aerobic power of various sports. Note that women have lower mVO2’s than men. Also note the decrease in mVO2 with age (the first 3 sedentary lines):
Men
Women
Anaerobic threshold (AT)
AT is defined as the percentage of an athlete’s aerobic capacity (mVO2) that he can exercise at before dipping into anaerobic reserves. In other words, how fast can he run before he goes into “oxygen debt” and begins to accumulate lactic acid. For the untrained exercisers the AT usually is around 55% of mVO2. For the elite athlete AT approaches 80% mVO2.
There is a high correlation between mVO2 and AT: they are both developed through the same biochemical and physiologic pathways. Genetics and heredity, including sex, confer a significant percentage of maximal aerobic power. Also the amount and length of preparation (in years) is reflected in mVO2. Endurance athletes consistently register the highest mVO2 values.
Exercise training can improve aerobic power by 20%. AT is a sensitive measurement of conditioning: the higher your AT, the better the shape you are in, and if physiologic preparation were the sole factor, the better your results would be. It is a more predictive of athletic performance than mVO2.
There is a significant decrease in aerobic power as we get older (4.5 ml/kg/min per decade). However, it has been shown that continued exercising dramatically slows this decline. In fact, inactivity results in a greater loss of maximum aerobic power than aging.
Training for aerobic power
There are four major workouts used to improve aerobic power.
Long slow distance (LSD).
LSD is best suited to develop general endurance and it should be the foundation in any preparatory period, including the off-season, and any rebuilding periods from illness or injury. Without a broad LSD base, any hard training will rapidly overload the athlete and result in fatigue and or injury. LSD probably develops the mVO2 almost exclusively because you never approach the AT.
What is LSD? It is doing the activity at a “conversational pace,” and performed for 3-5 times the race distance. It doesn’t matter what the activity you are doing, e.g. running, swimming, bicycling, LSD can be applied:
- A 5k running race of 20 minutes requires an LSD run of 60-80 minutes.
- A 40k cycling race needs an LSD ride of 2-3 hours.
- 2500 meter rowing ergometer race demands an LSD row of 45 to 60 minutes.
Ideally the first 4-6 weeks of training should include 3-5 LSD sessions per week (usually not more than 60 minutes per session).
The endurance events like the marathon, century ride or distance triathalon, require building up to LSD times that duplicate the expected race duration.Because you are developing basic endurance which can be correlated with cardiopulmonary improvements (mVO2), cross training seems ideal for LSD workouts. In other words, training for a marathon will stress the knees and feet as the distance increases. To prevent injury and still develop the energy system, substitute swimming or cycling for an LSD workout.
AT training.
The second aerobic power regimen is performed at or slightly above the anaerobic threshold. The pace is one at which the breathing becomes noticeable, but doesn’t limit you from exercising 20-60 minutes, depending on your conditioning and the event being trained for. This is hard work and it is somewhat difficult to perform psychologically because it can cause a certain level of discomfort. One AT workout per week is sufficient, if the following workouts are included.
Interval training.
Periods of work are interspersed with rest to restore the energy supply. From Specificity 1, recall there are three sources of energy: (1) ATP-CP (phosphagen stores), (2) LA (anaerobic glycolysis), and (3) aerobic metabolism. These systems are not mutually exclusive. Although they have different rates of utilization, they are intertwined because they rely on each other for replenishment.
When your level of effort exceeds the rate of aerobic metabolism, you get additional energy by breaking down glucose into lactic acid. This produces an “oxygen debt.” When effort stops, you continue to breathe hard because you are using oxygen to burn the LA for energy. It was first thought that the LA was converted back into glycogen. It is now believed that this is only a minor pathway. The glycogen stores are replenished by dietary nutrients, while most of the LA is oxidized for energy.
Fartlek training.
Fartlek is a Swedish term meaning “speed play.” It is a less rigid form of interval training performed on natural terrain. Fartlek training is based on “how it feels” at the time. For example, hard effort is used to push up-hill, and increased cadence is used on slight downhill sections. When done properly fartlek will develop all three energy systems.
Fartlek training can be applied to any sport by varying the work from 10-20 minute AT pace to short bursts at maximum effort. You must always include the appropriate rest intervals, some of which can be used for technique training, as well as recovery. It should be impromptu and “free-form,” performed within a basic time-frame, but according to no other preconceived work schedule. This produces a relaxed and interesting session, without the rigidity of pure interval routines.
You should do 1-2 fartlek sessions per week. Do more in the off-season, when recovering from a race or injury, and when there is a need for improved general conditioning.
