Appropriate swing direction of your body(arms, upper or lower body)
There are 2 types of getting rotation.
The one is to shift CG(the center of gravity) and pushing.
(cf. Slightly arch your back and jump)
And the other one is to swing your arms or upper body or lower body to be applied frictional force.
About the former one, we already understand.
The more vertical a force is applied to the direction of CG, the more we can get rotation.
However, we have not yet known which direction is better for rotation and which for height.
We’d like to say the conclusion beforehand.
If you swing your part in the opposite direction of CG, your CG get the utmost translation.
And if the direction of the translation is vertical to the ground, your flip get the utmost height.
If you swing your part vertically to the line which connect the part and CG, your flip gets the utmost rotation. (It’s difficult to understand. See the figures in the end.)
Assume that you have weights with your arms.
If you swing your arms and weights upward, your body will be pulled by the weights upward.
If the weights are moving horizontally, your arms are pulled by those to the direction of rotation.
Actually, translation does not mean height(but in most of the cases, it’s almost the same).
It is explained later.
Draw a line which connects your center of gravity(around your waist) and your hands in your takeoff form.
And add an arrow of your swing direction.
Draw in your form at the moment of takeoff
If the arrow is perfectly vertical to the line, you get the utmost rotation.
Like this
It is because he doesn’t jump, so he has to get rotation by only his arms.
If not, a part(vertical to the line) of your swing is for rotation.
And the other part(horizontal to the ground) is for translation.
Let’s think about the case in that you have a counterpart of one nunchaku and release it swinging the other part .
If you release the nunchaku at ①, it will fly upward with rotation. If at ②, it will fly horizontally with faster rotation than at ①However, taking into account easiness, people swing their arms downward almost always in front flips.
If your center of gravity is above your feet, translation is height at all.
If not, some part of translation becomes just a travel backward.
The direction of the line which is connecting the swung part and CG is the direction in which that swung part will rotate after launched. It is efficient for rotation to swing a part in the direction which the part will rotate in the air after launched.
In this page, only a swing of arms is focused but in reality, the movement of arms is the movement which is added the movement of the upper body to the movement of arms itself.
Therefore, the movement of an upper body should be considered.