AS biomechanics
- Created by: wistuart
- Created on: 09-03-18 09:23
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- AS Biomechanics
- Principles of biomechanics
- To analyze performance
- To refine and improve sporting technique
- To design new equipment to benefit athletes
- To prevent injuries of athletes
- Newton's laws
- 1.Inertia- A body will continue in a state or rest or constant velocity until an external force acts upon it.
- 2. Acceleration- The change in motion of a body is proportional to the force applied
- 3. Reaction- Every action has an equal and opposite reaction
- Equations
- Velocity= displacement/time taken (m/s)
- Momentum= velocity* mass (Kgm/s)
- Acceleration= (final velocity-initial velocity)/Time taken (m/s/s)
- Force= Mass* acceleration (N)
- Weight= mass* acceleration due to gravity (10m/s/s) (N)
- Net forces
- Net force= 0- This means that a body is in a state of constant velocity or a state of rest.
- Net force= 1- A body is accelerating
- A sum of all the forces acting upon a body
- Net force= -1- A body is decelerating
- Forces
- Vertical Forces
- Weight- The gravitational pull that the earth exerts on a body.
- Ground reaction force- The equal and opposite reaction to weight which is always present.
- Horizontal Forces
- Friction- The force that opposes the motion of two surfaces in motion.
- Factors affecting friction
- Roughness of the ground surface- increased roughness= increased friction
- Athletes running on rough rubberized trackes instead of grass
- Roughness of the contact surface- Increased surface of contact surface= increased friction
- Athletes running with spikes instead of trainers
- Temperature- increased temperature of contact surface and surface= increased friction
- F1 drivers have a warm up lap
- Size of normal reaction- By increasing the size of reaction friction is increased due to more force
- shot-putters have a bigger mass meaning they can throw harder and reduce over rotation
- Roughness of the ground surface- increased roughness= increased friction
- Factors affecting friction
- Air resistance- The force that opposes the motion of a body travelling through the air
- Factors affecting air resistance
- Velocity- increased velocity= increased air resistance
- The faster a runner goes the more Air resistance they will have
- Shape- the more aerodynamic the shape= less air resistance
- Cyclists use a teardrop helmet as it is more streamline than a conventional helemt
- Frontal cross sectional area- decreased frontal cross sectional area= reduced air resistance
- The crouched position of skiers in straights
- Smoothness of surface- the smoother the surface the less air resistance
- The smooth lycra suits of sprinters
- Velocity- increased velocity= increased air resistance
- Factors affecting air resistance
- Friction- The force that opposes the motion of two surfaces in motion.
- Measured in newtons
- Vertical Forces
- Analysis through technology
- Limb kinematics- 3d optical motion analysis- can be used to improve technique
- Force plates- measures ground reaction forces-focuses on power output-when an object makes contact the force plate produces an electrical output proportional to the force applies
- Wind tunnels- Used to develop drag reduction systems and used to see how aerodynamic an object is
- Centre of mass and stability
- Centre of mass- is the point at which the body is balanced from all points.
- stability is the ability of the body to reduce motion and stay at rest
- Factors affecting stability
- Mass of the body- The greater the mass of the body the greater the stability due to its increased inertia
- Prop forwards in rugby can withstand great applied forces
- Height of the Centre of mass- The lower the centre of mass the greater the stability
- When gymnasts land they bend their knees to avoid falling over
- Base of support- the greater the base of support the greater the stability
- When props move their feet further than shoulder width in a scrum
- line of gravity- the line that extends from the centre of mass downwards- more central the line of gravity to base of support the greater the stability
- A basketball player taking a free throw stands square
- Mass of the body- The greater the mass of the body the greater the stability due to its increased inertia
- Factors affecting stability
- Lever systems
- components of a lever; - lever (BONE) - Fulcrum (JOINT) -Effort (Antagonist MUSCLE) -Load(WEIGHT OR Resistance)
- 1st class- Fulcrum in the middle
- Extension of the neck
- 2nd class- Load is in the middle
- Ball of the foot in take off phase of a jump
- mechanical advantage- effort arm is greater than the load arm
- Ball of the foot in take off phase of a jump
- 3rd class- Effort is in the middle
- Flexion of the elbow in bicep curl
- mechanical disadvantage- load arm is greater than the effort arm
- Flexion of the elbow in bicep curl
- Principles of biomechanics
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