Biomechanics in PE

Biomechanics in PE

1. Motion

   • forms of motion
     • Translatory (linear)
       • All points in a body travel over the same distance at the same time
     • Rotary or angular motion
     • Curvilinear (non-linear)
     • Angular motion
       • Body moves around an axis of rotation
     • General or combinational
       • Combination of two or more types of motion
     • Projectile motion
       • Once released projectile follows a predetermined parabolic path only effected by gravity and wind resistance
       • Wing resistance affected by: surface area, weight, surfaces nature (feel) and angle of movement

2. Speed and velocity

   • Distance over time
   • Speed of an object and a direction

3. Summation of force, direction and impact

   • it is important for there to be no break in the transfer from one movement to the other
   • Each new movement should begin at the point that the last force has reached its maximum or at a point in which it begins to fade to maximise the end force
   • Impact = force x duration of the force
   • Elasticity - property of an object to allow restitution
   • Restitution effected by
     • Playing surface composition
     • Composition of the ball
     • Temperature
     • Striking implement
     • Speed of implement

4. Leverage

   • Effort - some degree of effort needs to be applied to ensure movement. In the human body this effort comes from the contracting muscles attached to skeletal frames via tendons.
   • Load - load is the resistance that the effort attempts to overcome
   • Fulcrum - somewhere in the lever system there needs to be a pivot point about which the effort and load arm rotate.
   • Levers act as a force multiplier or a speed multiplier

5. Newtons laws of motion

   • Inertia
     • A body at rest will stay at rest unless acted on by an unbalanced. Alternatively a body in motion in remain in motion unless acted on by an unequal force.
   • Force and acceleration
     • The acceleration of a body is directly proportional to the net force acting on it, but inversely proportional to the mass of the body
   • Action and reaction
     • Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object

6. Center of mass (center of gravity)

   • Point at which gravity acts on the object
   • Stability
     • The center of gravity must be situated over the base of support
     • Movement of the object must require the center of gravity to be raised (the more work needed, the more stable the object?
   • Direction of force
     • The direction that a force is applied in relation to an object's center of gravity affects the motion of that object

7. Equilibrium, static and dynamic

   • Static equlibrium occurs when the body is static or stationary
   • Dynamic equilibrium, process of alternating balance and unbalance
   • Stability effected by; surface friction, rotation movement and additional mass being added.

8. Improved technology and performance

   • Clothing
   • Equipment design
   • Facilities