biomechanics u3 sac2

general motion

a combination of movements

linaer motion

motion in a straight or curved path

angular motion

rotation around around an axis or fixed point

projectile motion

any movement that leaves the ground

speed/ velocity

ratio of the distance covered to the time taken

torque

is the tendency of an object to rotate (force x length of lever)

the factors that affect projectile motion

angle of release, speed of release, height of release

force

causes an object to accelerate (f= m x a)

what are the four types of force

friction, drag force, gravitational force, and weight

friction

occurs when two surfaces come into contact with each other, in sport we either want to increase or decrease friction

gravitational force

is the force of attraction between two bodies or objects

drag force

when an object moves through air or water it will experience a drag force

momentum

a measure of the amount of motion an object has and its resistance to changing that motion (momentum= m x v)

conservation of momentum

the total momentum of the system before collision, is equal to the total momentum after the collision

conservation of angular momentum equation

moment of inertia x angular velocity

moment of inertia

is a measure of an object’s reluctance to rotate

impulse

is equal to the change of momentum of an object (I= f x t)

how can an athlete increase the summation of momentum

BEST, Body parts, sEquence, Stability, Timing, and follow Through

Newton’s 1st Law

a body will remain at rest unless acted upon by an external force

Newton’s 2nd Law

force applied to an object will produce a change in motion in the direction of the applied force that is directly proportional to the size of the force

Newton’s 3rd Law

for every action there is an equal and opposite reaction

equilibrium

a state of balance where an object or body experiences no net force or torque acting upon it, resulting in either no motion (static equilibrium) or constant velocity (dynamic equilibrium)

stability

refers to the degree to which a body resists changing its equilibrium

balance

is the ability to control a state of equilibrium

factors affecting stability

base of support, centre of gravity, and line of gravity

base of support

the area bound by the outside of the body parts in contact with the supporting surface

line of gravity

an imaginary line drawn vertically downwards from the centre of gravity

centre of gravity

is the point around which the body’s weight is balanced

third class levers

the force is between the resistance and the axis

what is the resistance in a third class lever

the resistance is the weight of the object being struck

why are third class levers best

they require greater force to move a given resistance, but greater range of motion and speed are gained

mechanical advantage

is the ratio of the force produced by a machine to the force applied to it

what mechanical advantage do third class levers have

all third class levers have a mechanical advantage less than one meaning more effort is required to move resistance but causes an increased range of motion and velocity

Qualitative movement analysis (QMA)

is the assessment of human technique, with the aim of providing appropriate intervention to improve performance

what are the principles of a qma

preparation, observation, evaluation, and error correction

preparation

is the specific purpose of the analysis, research goes into the features of the movement and the psychological and personal variables of the qma

observation

the purpose of this is to gather and organise the information

evaluation

they have to decide what the problem is, what could be causing it, and how to address it

error correction

now that weaknesses have been identified, strategies are then created to address these issues and are then developed using either direct or constraints based coaching