The Physics of Brazilian Jiu-Jitsu

by nighinar2016

Brazilian Jiu-jitsu is torque in action. Brazilian Jiu-Jitsu is a martial art that uses leverage and force to apply joint locks and chokeholds to defeat the opponent. It has the concept of a smaller, weaker person being able to defend themselves against a much larger, heavier person. Seeing as a smaller person may not have as much strength against the larger person, they can use BJJ techniques such as joint locks to still win. Joint locks and Choke holds use torque to inflict pain. If a smaller person wishes to win, they can use the idea of torque and create levers using the human body. By apply force to these levers, a submission will be created. It is important for BJJ fighters to understand torque and use it to their advantage; without understanding levers and force, a heavier person could easily defeat a weaker person.

Why does Jiu-Jitsu follow this progression? 

  1. Get your opponent to the ground
  2. Get past your opponent’s legs
  3. Control their hips and shoulders
  4. Add a submission

This progression is important because it neutralizes the opponent’s ability to throw the fighter’s balance off and use a submission on the fighter. It is especially important if the fighter is smaller, this progression gives the smaller opponent advantage seeing as the control is given to the fighter and not the opponent. Once control is established, the fighter is able to create locks (fulcrums) and apply force to create a submission and win the match.

Why does Brazilian Jiu-Jitsu want control?

Control gives the fighter the ability to use the opponent’s centre of gravity and limbs against them. They have the ability to choose where the force is applied and how to create a submission.

Determine the Lever, Fulcrum, Force, and Torque of Joint Locks

Kimura  In this joint lock, the fight uses the opponents forearm to create a lever. The fulcrum is created at the elbow with the fighters arm under the opponents elbow so it does not move. The force is being applied by the fighters another hand. This submission shows the control of the fighter over the opponent and how he uses this torque to inflict pain and have the opponent tap out. The calculation of torque is F x d
Armbar In this joint lock, the fulcrum is created at the shoulder with the hip keeping the fulcrum intact. The whole arm becomes a lever, it is not allowed to bend because the arm is rotated in a certain direction. The force applied at the hand can break the elbow. This submission uses torque to have the opponent to tap out. The calculation of torque is F x d

Determine the Lever, Fulcrum, Force,  and Torque of a Choke

Bow and Arrow The fulcrum here is created at the hip, the leg of the fighter holding it in place to not move. There are two forces being applied, F1 causing a clockwise rotation and F2 causing a counter-clockwise rotation. In this submission, F1 causes force on the throat which therefore causes a choking submission. F2 is responsible on balancing F1 so F1 has enough impact to cause a submission. The calculation of torque is (F1 x r1) + (F2 x r2) if we assume that the forces applied are at 90 degree angles (perpendicular to the lever).

 

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