Physical conditioning is a result of balanced nutrition integrated with an exercise programme of appropriate intensity, duration and type, carefully periodized over an extended period which includes sufficient recovery phases to repair cells, regenerate energy stores and encourage supercompensation.
The development of a specific fitness component depends on altering the intensity, duration and type of exercise.
Normally, power and strength rely strongly on the high energy phosphagen system, muscle endurance on the oxygen independent glycolytic system and cardiovascular endurance on the oxygen dependant energy system.
However, this can conceal the fact that for example, the metabolic demands often change from moment to moment during every type of action taking place in sport.
Endurance events such as cycling, long distance running and cross country skiing use the oxygen dependant aerobic system.
However, there are moments of acceleration and increased muscular work which puts significant demands on the anaerobic (phosphagen) and intermediate (glycolytic) systems.
On top of this, while the cardiovascular demands in endurance events may be relying on aerobic systems, it cannot be overlooked that forcefully contracting stabilisers and active muscles may be dependant on anaerobic systems at the same time.
This means that exercise programmes should not rely on the analysis of just one aspect of athletic performance.
It would be intelligent to include phases of high intensity strength and speed training even for endurance events.
