Movement analysis
Lever systems
Mechanical advantage
Analysis of basic movements in sporting examples
Planes and axis of movement
- First class lever: In summary, in a first class lever the effort (force) moves over a large distance to move the load a smaller distance, and the fulcrum is between the effort (force) and the load. As the ratio of effort (force) arm length to load arm length increases the mechanical advantage of a first class lever increases.
- Third class lever: When you lift a load using your forearm you are using a third class lever. Your biceps muscles are attached to the forearm just in front of the elbow. The load is on the hand, and the effort is between the fulcrum (elbow) and the load
- In a second class lever: The effort moves over a large distance to raise the load a small distance. As the ratio of effort (force) arm length to load arm length increases, the mechanical advantage of a second class lever increases. In a wheelbarrow, the closer the load is to the wheel, the greater the mechanical advantage.
Mechanical advantage = effort arm ÷ resistance arm
- Flexion = Is the bending of a particular joint so that the bones that form that joint are pulled closer together.
- Extension = a physical position that increases the angle between the bones of the limb at a joint. Typically, an extension of a joint is limited to 180 degrees or less. In other words, that joint can basically be opened until it is straight.
- Abduction = is movement away from the mid-line of the body.
- Adduction = Movement towards the midline of the body, an imaginary line running down the middle of a body or any limb, is called adduction.
Planes
1) Sagittal plane - a vertical plane that divides the body into left and right sides. Flexion and extension types of movement occur in this plane, eg kicking a football, chest pass in netball, walking, jumping, squatting.
2) Frontal plane - passes from side to side and divides the body into the front and back. Abduction and adduction movements occur in this plane, eg jumping jack exercises, raising and lowering arms and legs sideways, cartwheel.
3) Transverse plane - passes through the middle of the body and divides the body horizontally in an upper and lower half. Rotation types of movement occur in this plane, eg hip rotation in a golf swing, twisting in a discus throw, pivoting in netball, spinning in skating.
Axis
click to edit
1) Frontal axis - this line runs from left to right through the centre of the body. For example, when a person performs a somersault they rotate around this axis.
2) Sagittal axis - this line runs from front to back through the centre of the body. For example, when a person performs a cartwheel they are rotating about the sagittal axis.
3) Transverse axis - this line runs from top to bottom through the centre of the body. For example, when a skater performs a spin they are rotating around the vertical axis.