Category Archives: Grade 12

Brazilian Jiu Jitsu and Physics

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Torque is the main concept of physics that is used in Brazilian Jiu Jitsu as it a great method when causing an opponent to submit. This martial art uses leverage and force to apply joint locks and chokeholds on the competition. In this sport size is not a skill-determining factor as a smaller competitor can inflict pain on his/her larger competition due to the use of torque. Many of the moves involve exceeding the motion (or hyperextending) of a limb by putting pressure past what the fulcrum can handle.
Torque: a measure of how much the force acting on an object causes that object to rotate. The object rotates about an axis, which is called the pivot point or point of rotation.
Force: any interaction that will change the motion of an object.
Fulcrum: a pivot point around which a lever turns.
Lever: the perpendicular distance from the axis of rotation to the line along which the force acts.
Center of gravity: the point at which the system’s whole mass can be considered to be concentrated for the purpose of calculations.

Armbar

Kneebar

How does a Brazilian Jiu Jitsu practitioner’s understanding of physics (torque) make him or her more effective?

A competitor does not have to be very strong or large to win a competition when using torque effectively. This makes it so that everyone, no matter the size or strength, can successfully take an opponent down and win a match.

Neuron Communication

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Neuron Structure

The function of a neuron is to process and transfer information. A neuron is composed of many structures to allow it to carry out these functions daily. The neuron consists of dendrites, a cell body, axon, myelin sheath, and terminal buttons. The functions of these structures is explained in the diagram below.

Neuron Types

There are three types of neurons; the motor neuron, sensory neuron, and the interneuron.

Motor Neuron

Motor neurons are part of the central nervous system and connect to the muscles, glands, and organs in the body.

Sensory Neuron

Sensory neurons are activated by sensory input from the environment and send information to the brain when stimulated.

Interneuron

Interneurons consist of the neurons that connect sensory neurons to motor neurons and vice versa, assisting in the transfer of information.

Action Potential

Action potential occurs when a neuron is stimulated. Prior to an action potential, a neuron is in resting potential where the axon is in a polarized state with a charge of -70 millivolts relative to the outside of the axon. During resting potential, the fluid inside the axon has more negatively charged ions than the fluid outside. Next, depolarization occurs when channels open in the membrane of the axon to allow sodium ions to enter, creating a balance of ions. Therefore, depolarizing the inside of the axon. This has a charge of about +30 millivolts. More channels then open to allow potassium ions to exit, repolarizing the axon (-70 to -80 millivolts). The recovery period involves the action potential continuing along the entire length of the axon from the cell body to the terminal buttons.

Synapse Structure & Function

The synapse is a gap between the axon of one neuron (sending neuron) and the dendrite of another (receiving neuron). The terminal button of a neuron wants to release chemical messengers (neurotransmitters) from the axon to pass on information to another neuron. This is how neurons “communicate” with one another and can be visually demonstrated by the diagram below.