Biomechanics

Definition

The study of motion and the effects of forces relative to the body.

Benefits

• technique efficiency

• injury reduction through an understanding of injury causes and application of correct technique

• modification of sports equipment to improve sports performance at all levels

• technological development of equipment and computer technology to assist in transition from practice field to playing field

Motion

The movement that occurs when an object has changed position in space and time, due to the application of forces.

Internal Force

Structures of the body that interact to produce movement. action of muscles and tendons to throw a ball)

External Force

Result from the interaction between the body and environment. (gravity, friction, air resistance)

Linear Motion (translation)

Where movement is along a straight line, there’s no rotation and all body parts move in the same direction at the same speed. (cyclist gliding downhill)

Rectilinear Motion

Linear movement of an object in a straight line. (volleyball set that doesn’t spin)

Curvilinear Motion

Linear motion of an object in a curved line.(netballer shooting as long as the ball doesn’t spin)

Angular Motion

Where all body parts move through a rotational pathway, through the same angle, in the same direction and at the same time. (gymnast doing giant circles on a bar)

Locations of Angular Motion

• medial axis - naval to lower back (gymnast performing cart wheel)

• longitudinal/sagittal axis - head to toe vertically (dancer doing pirouettes)

• horizontal axis - hip to hip (diver performing somersault)

General Motion

Combination of linear and angular motion. (cyclist moving in a straight line as a result of rotating the legs at the hip joint to move pedals)

Distance

Refers to how far you have travelled from your start to finish position.

Displacement

Measures the overall change in a position of a person and is measured in magnitude and direction.

Speed

Measure of the distance an object travels per unit of time (distance/time)

Velocity

Speed in a given direction (displacement/time)

Acceleration

Rate at which the velocity of a body changes with respect to time. (positive - increasing, negative - decreasing, zero - no change)

Angular Distance

Represents the sum of all angles as a body that moves from its start position to its end position.

Angular Displacement

Represents the difference in the angle between the start and end position of the body.

Angular Speed

Calculated by dividing angular distance by time.

Angular Velocity

Calculated by dividing angular displacement by time.