lesson 11 principles

THE PRINCIPLES OF BIOMECHANICS BY: JAMIE BRYNN HAMILTON

AN INCREASE IN ACCELERATION EQUALS AN INCREASE IN FORCE. IF YOU WANT TO DOUBLE THE ACCELERATION, YOU NEED TO DOUBLE THE FORCE.

In order for the sprinter in this picture to achieve maximum acceleration, he must produce as much force as is bodily possible in his takeoff. In the above example, this translates to pressing off the starting step with all of the power he can through his back leg.

AN OBJECT WILL CONTINUE MOVING AT A CONSTANT SPEED AND DIRECTION UNLESS ACTED UPON BY A FORCE THAT CAUSES ITS SPEED OR DIRECTION TO CHANGE

The tennis ball will continue in its trajectory unless acted upon by an outside force. In this case, the tennis player will utilize the racket to produce equal or greater force than that of the travelling ball, in order to hit it back in the other direction.

FOR EVERY FORCE, THERE IS AN EQUAL AND OPPOSITE REACTION FORCE

The fighter is producing force to kick her foot towards her training partner. The training partner with the pad is returning the kick with equal reaction force so that he is not knocked backwards.

YOU MUST APPLY FORCE IN THE DIRECTION THAT YOU WANT TO TRAVEL

The runner is apply force to the ground behind her. She is also simultaneously pumping her arms in a vigorous forward cycling motion, which creates momentum that allows her to move in a forward direction faster than if her arms were just dead weight at her sides.

YOU CAN IMPROVE PERFORMANCE BY REDISTRIBUTING THE MASS OF THE BODY ABOUT THE CENTRE OF GRAVITY

The athlete in the pictures has her mass distributed too far into her posterior. A more ideal body position would be having her weight right around the midfoot of her body, thus allowing the greatest opportunity to apply linear force directly UP. The position she is in right now is unbalanced.

BY INCREASING YOUR BASE OF SUPPORT AND LOWERING YOUR CENTRE OF GRAVITY, YOU WILL INCREASE YOUR STABILITY

A narrow base of support is easily toppled by outside forces. Lowering your centre of gravity also decreases your height and essentially makes you more gravitational stable; there is less outside force acting against the body to make you lose balance.

IN ANGULAR MOVEMENT, THE MAXIMUM EFFECTIVE FORCE AND VELOCITY OCCUR WHEN THE LIMB IS AT RIGHT ANGLES TO THE BODY

Right angles are powerful because the limbs are not at excessive flexion or total extension. Muscles are firing to maintain this position versus in a state of relaxation, thus allowing for maximum force and velocity potential.

ENERGY IS CONSERVED BY NOT PAUSING BETWEEN TWO MOVEMENTS THAT ARE BOTH LINEAR

The contact with the ball and post-kick follow through by the soccer player both occur with the leg travelling in a linear motion. Were the player to stop immediately after making contact with the ball, the energy required by his body to halt all of that forward momentum would be far superior than allowing his leg to continue on the follow-through trajectory.

BY USING A TOTAL RANGE OF MOTION AND MAKING USE OF THE NATURAL LEVERS OF THE BODY, GREAT MUSCULAR FORCE CAN BE ACHIEVED

A total range of motion and proper lever use not only mean the proper technique can be applied in any movement. Effort and energy consumption are also lower, because the body is moving most efficiently for that specific movement.