Energy & Work Capacity 2

In the second part of the energy & work capacity series we are going to take a closer look at specificity of the aerobic component.

Whilst it is a given that all athletes need to develop their aerobic component of fitness, the fundamental question is how to best develop the aerobic power necessary for recovery from short bursts of activity that occur in game scenarios without compromising explosive power necessary for optimal performance during the spurts.

Aerobic Power = Highest peak oxygen uptake that an individual can obtain during dynamic exercise using large muscle groups during a few minutes performed under normal conditions at sea level.

Explosive Power = Power is specifically Force*Velocity, often referred to as strength*speed and refers to an individuals ability to exert strength as rapidly as possible in a given action.

There are vast amount of research literature and papers covering the various factors of aerobic exercise, this is due to the fact that it is easily measurable in the form of VO2 max. Although it is a useful measure to know an athletes aerobic capacity, it is not the be all and end all, and can often be an overrated measure, particularly in team sport athletes. For example, you might have a rugby team who put excessive emphasis on aerobic fitness and can run forever, but they don't have the all important bursts of power and speed necessary to win the game. Evidence has shown that sustained aerobic work will significantly compromise explosive power, by focusing on training of aerobic nature our fast twitch Type IIa and Type IIax muscle fibers (explosive) will be converted to Type I slow twitch meaning we won't have the same physiological muscular capacities to produce the explosive movement desired. Therefore, the challenge is to train the aerobic component without compromising the explosiveness required during the bursts.

ALTERNATIVE MEASURE

Billat (2001)(French Sports Scientist) illustrated in her research that in one session an athlete can contribute to the improvement of:

- Lactate Threshold (minimum velocity at which lactate begins to accumulate in the blood, point where lactate removal by the muscles can't keep up with production by the muscles)

- vV02max (slowest running economy that can still elicit VO2max)

- Running Economy

To understand the research we must understand two variables of VO2max, these are vVO2max (described above) and tlimvVO2max (time the athlete is able to work at VO2max). Billat et al Research (2000) has suggested that vVO2max and tlimvVO2max are better indicators, and more importantly these measures enable you to derive a precise training velocity for interval research (because precision requires more than guess work)

TEST PROCEDURE

- On a standard 400m track in still wind conditions, an athlete runs as far as possible in six minutes.

- Record the distance run in meters.

- To determine vVO2max divide the distance run in meters by time of the run in seconds. The time is always 360seconds (6*60)

- For example if the athlete can cover 1560 meters that would be divided by 360, indicating a vVO2max of 4.3metres per second.

It is imperative to repeat the test every 6-8weeks to determine the new levels. In Billat's original research using 6 workouts per week consisting of four easy sessions, one session at vVO2max and one at lactate threshold for four weeks she was able to get a 3% increase in vVO2max and a 6 percent increase in running economy. Hence, it is possible to increase our aerobic power and work capacity without running for hours and limiting our explosiveness.

Sports Medicine

January 2001, Volume 31, Issue 1, pp 13–31

Interval Training for Performance: A scientific and empirical Practice

http://link.springer.com/article/10.2165/00007256-200131010-00002