Karaté - Budo

Eléments essentiels à la compréhension du karaté Physical principles of karate

### Kinetic Energy: 1/2 mv²

Kinetic energy, i.e. the energy of a moving body, depends on its mass and velocity. In physics, kinetic energy is defined by the following formula: KE = 1/2 mv² where KE is kinetic energy, m mass and v velocity. Kinetic energy is expressed in joules.

We understand, therefore, that the greater the mass and velocity of a blow, the greater the kinetic energy will be.
Mass is linked to the weight of an individual and the technique employed. For example, with a gyaku tsuki, the mass involved is the mass of the arm; but if we add a twist of the hips, the mass of our moving trunk will significantly increase the kinetic energy.

The speed of a blow is very important because it is squared when calculating the kinetic energy. Muscle relaxation, coordination and explosiveness are crucial for increasing the speed. Technique is also important, because in the gyaku tsuki (for example) the speed at which the hips are twisted is added to the speed of the arm extension and the rotation of the fist. If we look at a moving oi tsuki, the entire body advances and the speed of the lower limbs intensifies the energy delivered.