To optimise an effort, it is essential to dilate the arteries which irrigate the muscles. - Vasodilation phase.
To increase the circulation of oxygen, to supply the muscles during the effort.
To stimulate the nervous system to obtain shorter response times during the sport.
It is as important to stimulate the motor system as the sensitive system: for example in a cross-country run, good stimulation of the foot will avoid spraining the ankle if you put the foot in a rut.
Progressively loosen up the joint to avoid damaging the ligaments and the tendons.
By warming up, you prevent many muscular accidents: cramps and strained muscles for example.
But also respiratory problems: stitches.
Start by jogging gently, making full arm and leg movements in order to progressively activate the cardio-vascular system.
Then do a few dynamic stretching movements.
Continue with warming up specific to your activity: movement and rhythm.
For more sophisticated warming up exercises, include massages and passive stretching with partners three to four hours before the competition.