WingChun Physics 101: Punch Energy and Momentum

Energy exists in many forms. Your energy comes from what you eat, because your body turns the food into chemical energy.  It is turned into mechanical energy in your muscles, which is used to punch an opponent.  Depending on the factors at the point of impact, the energy of your strike can turn into sound energy, thermal energy, kinetic energy to move the opponent and/or to locally change in its structure, such as bruises and pains.  When energy changes forms, energy is conserved. No energy is lost.

In WingChun, how can I punch harder?

There are two type of punches:

  1. Momentum Punch: heavy punch to move your opponent, i.e. knock one back/out
  2. Energy Punch: fast and painful that causes more pains and bruises

WingChun Momentum Punch

Momentum is the force gained by a series of motions with magnitude and directions in 3D space. Do you remember the Newton’s Second Law of Motion? What happens to a body when an external force is applied to it?  In momentum, the amount of changes to the body is equal to the net force acting on it.

This is written in mathematical form as P = mvP is momentum, m is mass, and v is the velocity. It has a specific direction assigned to it.

High momentum strike is a powerful tool to have in fight. It can push your opponent back, knock him off balance, knock him out if the strike leads to one’s head rotate.

Mass and velocity are multiplied together to increase the momentum of the punch. More momentum means finding the way to put more weight behind your punches.  Your knuckle is less than 1 percent of your body weight. Consider dealing with 200-pound man approaching or least his head to spin-around. Average person can throw punch at 10-15 mph (miles per hour), or even more trained practitioner can through it in maybe twice faster, like 20-25 mph.  You need to find the way to use more mass than just a fist. Right?

Train to put more mass behind the punch. Coordinate your body parts, arms, shoulders, spines, rib cage, hip, feet, gravity, and timing of air exhalation, from preparation of the punch to the impact.  Even if you are to put 5-10 percent of your body weight behind the punches, you can improve the momentum of the punch for 10 to 20 times, while combining other factors, which are a lot more involved.

WingChun High Energy Punch

Kinetic energy is the energy of motion.  The equation is KE= 1/2mv m is mass, and v is the velocity. It means that the kinetic energy of an object is directly proportional to the square of its speed. If speed increases in twofold, the kinetic energy will increase by a factor of four. It has the strong favoritism to the speed. So, if you want to get the most energy from your punch, increasing the speed is your primary goal.

Collisions: Energy Transfer and Impulse

Upon collision, intensity of energy is transferred per unit area.  So, if there are smaller surface used as a contact for the punch (bone parts of the knuckle versus palm strike), the localized damage is more severe. In addition, the impulse (J), which is the integral of the the resultant impact force (F) is J = ∫ F dt = m Δv =F t. m is mass, and Δv is the changes in velocity, t is the time during the collision.  It means in order to achieve high Fincreasing the Δv and decreasing the t will do the job.

What does it means in WingChun punch?  We can also improve our punch by decreasing the collision time, and increasing the punching speed (toward opponent and “quick pull” of your fist at the moment of impact). If you are wearing a traditional WingChun uniform, you can hear the sound of your sleeve snap with your fist.

Energy Transfer and Efficiency in Interactions

This fundamental physics is also applicable to kicks, palm strikes, and pak sao, etc.  For example, we always emphasize not to holding onto the opponent’s arm after the pak sao. It’s one of the many reasons.  When you grab and attempt to control the opponent, it increases the time during the collision and half of Δv (the change in velocity), and your momentum ends there.  It lowers the efficiency of the energy transfer in combat.  Same in life, sometime, to lose control is the best possible thing that can happen to us.  It releases us from the pain that comes from expectations, and teaches us to be calm and be ready for the next things.  Pak sao then punch the opponent at the best you can do, once completed the task, go back to the wu sao position and get ready for the next.

It can take years of training to reach to the point where you feel coordination of the body, enable to put significant mass behind your punches, and improve the details of the basic techniques.  It will take a lifetime to reach the perfection, because once you get advanced, your sense of awareness advances,  you will always start finding more room to improve yourself. And small advancement, feeling of small success in a daily life, get yourself inspired, and inspire others.  By training yourself hard, you are making the world slightly better.  Isn’t it fascinating?

If you have the guts to keep making mistakes, your wisdom and intelligence leap forward with huge momentum.Holly Near

Sije Yuka Yoshioka

WingChun Physics 101 – Intro to Izzac Newton’s Laws

May the force be with you! Remember Issac Newton’s First Law of Motions, “a body at rest will remain at rest, and a body in motion will remain in motion unless it is acted upon by an external force.”

What, then, happens to a body when an external force is applied to it? That situation is described by Newton’s Second Law of Motion.

“Force is equal to the change in momentum per change in time. For a constant mass, force equals mass times acceleration.” This is written in mathematical form as F = ma.

F is force, m is mass and a is acceleration. The math behind this is quite simple.

Force is the power of punches, Pak Sao, Tan Sao, Bong Sao, and more. Yes, understanding the physics behind it would significantly help you toughing up and up!

a is the acceleration, change its velocity, at a constant rate. So, in order to get the most efficient acceleration at the impact, you need to know the optimum distance for your techniques, where your hands reaches to maximum speed.

In WingChun Physics, F and a are in vector quantities, which means they have both magnitude and direction. The force can be the combination of more than one force. In this case, we would write the equation as ∑F = ma.

Think about the mass of fists, combining with the different parts of your body and angles, with the strong stance, adding more power source from stance shift and steps, the possibility of maximizing the force by training is almost infinite.

Therefore, we emphasizes a lot in the proper preparation, timing, precise motions, and stances in WingChun.  And WingChun practitioners have tendency to progress and transform significantly faster, once he/she started to grab this feeling of flows and coordination.  Indeed, it is under the multiple phases and reaching each stage feels really great. Let’s Feel the Force!

Sije Yuka Yoshioka