Biomechanics Flashcards
Levers
(1st class lever)
A see-saw lever.
EFL
Ex, tríceps extending at elbow when throwing a ball with the hand.
Levers
(2nd class)
FLE
The load is bigger than effort, and fulcrum is at the end of the lever.
Ex, when doing a plantar flexion, the fulcrum is in the toes of the foot, the load is the leg and the gastrocnemius and soleus are the effort.
Levers
(3rd class)
FEL
Fulcrum at one end of the lever arm, with the effort between load and fulcrum.
Ex, Biceps curl, Elbow is the fulcrum and biceps effort the weight is the load.
First class lever adv and disadv
-Adv: Has fulcrum in middle and effort and resistance on the 2 sides.
-Disadv: The fulcrum relies on more effort or more force.
Second class lever adv and disadv
-Adv: Effort arm is long so muscles can provide lots of force.
-Disadv: Small range of movement because short resistance.
Resistance cannot be moved quickly because force is applied further away from fulcrum.
Third class lever adv and disadv
-Adv: Wide range of movement because of long resistance arm.
Resistance can be moved quickly because force is applied close to the fulcrum.
-Disadv: Can’t provide much force because effort arm is short.
Newton 1st law of motion
Law of inertia
A body continues in its state of rest or of uniform motion unless a force acts on it.
The more mass object has = more inertia.
Ex. Basketball has more inertia than golf ball.
Newton’s 2nd law of motion
Law of acceleration
The acceleration of an object is directly proportional to the force causing it and is inversely proportional to the mass of the object.
To calculate force you need the mass of object and acceleration.
Ex. Riding a bicycle, mass is the bicycle and you pedaling is the force. That is acceleration.
Newton 3rd law of motion
Law of action and reaction
For every action there is an equal and opposite reaction.
Ex, if you throw a bullet eventually is going to fall to the floor, due to the forces acting against it.
Center of mass
The point of balance of the body.
Gravity acts on mass to produce weight, the weight acts at the center of mass of the body.
C of M does not always lie within the body shape, when the torso is bent, it can lie well outside the body mass.
Balance
The Centre of Mass has to be over the base of support for a person to be balanced.
Toppling is caused by
Weight acting vertically at the center of mass. So on one side of the near edge of the base of support.
Stability
Equilibrium and unstable equilibrium
If an object has its center of mass over the base of support, it is in equilibrium.
If a slight movement of the object will make it topple, the object is unstable equilibrium.
Ex, beam gymnast controlling C of M to remain on beam.
Response of Muscular system to warm up.
-Raises heart and cardiac output. So more blood is pumped to working muscles.
-Improves elasticity of muscles fibers, so greater strength of contraction.
-Increase speed of nerve transmissions to muscle fibers, so faster speed of contraction.
-Increase in muscle temperature, so faster speed of contraction and relaxation.
-Reduce muscle viscosity so improvement in coordination between antagonistic pairs, therefore increased speed and strength of contraction.
Response of skeletal system to warm up
-Good warm up increases amount of synovial fluid in joints, so they can move more smoothly. Also prevents injuries.
-Prepares tendons to improve stability and contractile activity of skeletal muscles that are ready to react to increased activity.
