Biomechanics Yr 2

Final position-initial position (M, rads, revs) Is a vector quantity since it has a magnitude and direction

(Final position-initial position)/time Velocity is a vector quantity since it has magnitude and direction

(Final velocity-Initial velocity)/time Acceleration is a vector since it has magnitude and direction

Time, position, displacement, velocity and acceleration

How long the cameras shutter is open for

To scale measurements

• are you too close to the area of interest • are you perpendicular to the plane of motion • is the camera at the correct height

Pan- ensure full width of action is visible Roll- ensure camera is level Tilt- ensure camera is angled directly perpendicular to the movement Camera height- should be same height as the area of interest Zoom- eliminate useless space in capture volume

Sampling frequency- how many frames per second Shutter speed- how long each frame is captured for Iris- how wide is the aperture of the camera

Kinematics describes the observed motion (focuses on the geometry of motion of objects: such as displacement, velocity, acceleration…) Kinetics explains how the observed motion was achieved. Study of the forces acting within a body and the changes they produce in the body itself.

Force x Change in time

Mass x Change in velocity

Internal- acting between body parts External- acting between the body and the environment Gross mechanical effects- influence body movement Local biological effects- contacting tissues

• force transducers and sensors/load cells • capacity to be used in Vivo • force platforms • pressure plates

Y- anterior-posterior Z- vertical direction X- medio- lateral

• vertical force • vertical impact and vertical force • impulse measure of the effect of a force during the time that the force acts

Force= mass x acceleration Moment= force x perp. distance Impulse= force x time Momentum= mass x change in velocity Impulse= momentum

Work (J)- whenever force is used to move something Energy (J)- ability to do work/apply a force Power (W)- how quickly work is done

Mechanical work is a measure of the transfer of energy from one object/body to another. Work done by a force on an object= the magnitude of the force multiplied by the displacement of the object along the line of the force Work= force x displacement

The force is applied in the same direction as the resulting movement

The force is applied in the opposite direction to the resulting movement Often associated with eccentric exercise

Energy of motion The energy possessed by a body because it is moving

Energy of position Stored energy which can become kinetic due to relative height or deformation

Due to relative position above a surface PE= weight x height PE= mass x gravity x height