movement analysis + biomechanics Flashcards
Newton’s first law
- law of inertia
- object stays in rest or motion unless an external force is exerted
- ball is still until kicked by player
Newton’s second law
- law of acceleration
- rate of momentum is proportional to the force causing it, in the direction in which the force acts
- when a player kicks the ball, the acceleration of the ball is proportional to the size of the force so the harder it’s kicked, the faster it will go.
Newton’s third law
- law of reaction
- every action has an equal and opposite reaction
- when jumping for a header, the force put into the ground is equal to the force out of the ground so the more force in the ground, the higher the jump
what does a positive net impulse mean + when during a race
there is acceleration
at the start of the race
what does zero net impulse mean + when during a race
there is constant velocity
midway through the race
what does a negative net impulse mean + when during a race
there is deceleration
at the end of the race
define motion
the change of location or position of an object with respect to time
internal forces
muscle contraction - usually concentric
external forces
gravity, air resistance, water resistance, friction and reactional
linear motion
the straight line movement of an object. all parts of the body move in the same direction, at the same speed when acted upon by a force
scalar quantity
a quantity that only has magnitude (size).
e.g mass, speed, distance
vector quantity
a quantity that has magnitude and direction
e.g displacement, velocity, acceleration, force
distance vs displacement
distance - total length from point A to point B
displacement - how far it is from its original position
scalar formula triangle
speed (m/s) = distance (m) / time (s)
vector formula triangle
velocity (m/s) = displacement (m) / time (s)
how to find velocity from a displacement time graph
- straight horizontal line = zero
- constant velocity (+/-) - find gradient
- variable velocity - draw tangent at a point and find gradient
acceleration (definition + equation)
- the rate at which velocity changes with respect to time
- acceleration (m/s2) = final velocity - initial velocity / time
angular motion
the rotation or circular movement of a body around an axis or a point
angular momentum (definition + equation + key point)
- the quantity of rotation of a body/object
- angular momentum = angular velocity x moment of inertia
- will remain constant
angular velocity
the rate at which a body rotates around an axis (speed of rotation)
moment of inertia
resistance of a body to change state when rotating (how performer distributes their mass around their axis of rotation)
- when angular velocity increases, moment of inertia…
- when angular velocity decreases, moment of inertia…
- decreases
- increases
angular displacement definition
the change in angular position of a body
angular displacement triangle
angular displacement (rad) = angular velocity (rad/s) x time (s)
angular acceleration (definition + equation)
- the rate at which angular velocity changes over time
- angular acceleration = change in angular velocity / time
moment of inertia can be influenced by….(2)
- mass of object - larger mass, larger moment of inertia
- distribution of mass away from axis of rotation - further away, greater moment of inertia
projectile definition
an object or body that’s released into the air
trajectory definition
the flight path of a projectile that consists of two components
two velocity components
vertical + horizontal
factors that affect trajectory (6)
- angle of release
- speed/velocity of release
- height of release
- gravity
- air resistance
- weight
angle of release
- 45 degrees is optimum
- affects both velocity components
- varies depending on sport
speed/velocity of release
- greater velocity, greater horizontal displacement
- largely determined by muscle force
- refers to law of acceleration
height of release
- greater height of release, greater horizontal displacement
gravity
- affects vertical component
- 9.82m/s^2
air resistance + factors affecting air resistance
- affects both components
factors:
1. surface area
2. type of surface
3. speed
4. mass
weight
mass x gravity
greater mass of object, greater influence of gravity upon it
vertical component
parabolic vs non-parabolic
parabolic - symmetrical
non-parabolic - non symmetrical
aerofoil
an object where the air flow travels further over the top of the projectile than the air passing underneath
bernoulli principle
refers to the lift force and downforce created when air flows over an aerofoil
upward lift force
top:
further
faster
lower
bottom:
shorter
slower
higher
pressure differential - causes lift
application of upward lift force
discus can hang in the air for longer resulting in an increased horizontal displacement/discus thrown further
downforce
top:
shorter
slower
higher
bottom:
further
faster
lower
pressure differential - downforce
application of downforce
rear wing
keeps car on floor so it can turn corners at high speeds, achieving the greatest lap time
magnus effect
the bernoulli principle applied to spinning objects
top spin
hit at top of ball
boundary layer forms
top:
collision with boundary layer
slower
higher
below:
smooth
faster
lower
pressure differential - magnus force down
top spin application
pulls ball down
attacking shots
shortening flight path
high velocity shots whilst keeping ball in court
forces opponent to baseline
back spin
hit off centre at bottom
boundary layer formed
above:
smooth
faster
lower
below:
collision with boundary layer
slower
higher
pressure differential - magnus force up
back spin application
defensive shot
lengthens flight path
ball hangs in air for longer so player can get back into position for next shot
fluid friction
used when referring to objects moving through fluids
air resistance
the force that opposes the horizontal motion of a body whilst moving through the air
drag
a force that opposes the motion of an object through fluid or air - slows velocity
factors that affect drag (5)
- front cross sectional area
- surface properties
- velocity of object
- surface area in contact with water
- mass of object
strategies to reduce drag
- cross sectional area:
swimming: head down, toes/fingers pointed, high on water
cycling: sat down, head forward
increases streamlining - laminar flow - surface properties:
swimming: swim cap, skin tight costume, shaving - increase smoothness
cycling: skin tight clothes, tapered goggles - surface in contact with water:
rotational technique
stay high above water
surface drag
skin friction/skin drag
refers to friction between surface and fluid environment
roughness of surface increases drag
form drag
shape drag/profile drag
when air/water come into contact with object
pressure on front is high, pressure at back is low
form drag application (cycling)
- front cyclist creates a pocket of air behind them
- riders behind conserve energy
- all riders conserve energy because theres less turbulent flow behind each rider
- slip streaming
laminar flow
- streamlined shape increases this
- fluid moves smoothly
turbulent flow
- less streamlining increases turbulent flow
- irregular fluctuations
- changes in direction
technology impacts four populations
- performer
- spectator
- officials
- coach
how and when can technology be used for performer
- pre, during, post
- target key aspects in training
- analysis of performance
- analysis of opposition
support them with:
training
technique
equipment and clothing
enhance recovery management
how and when can technology be used for coaches/sport scientists
- performance monitoring and analysis
- biomechanical analysis
- quantitative data
- nutritional monitoring
- recovery management
- communication and collaboration
how and when can technology be used for officials
- communication - between officials or with spectators
- helps with fair decision making
- reduces pressure on officials
how and when can technology be used for spectators
- camera coverage - provide different angles
- statistical information
- interactive software - more engaging
- digital media - follow a wide range of sports
- social media - personal link to sports people
additional points about technology
increased:
-access
-facilities
-equipment
-monitoring of exercise
-safety
reduced participation due to:
-cost
-alternatives (consoles e.g)
advantages and disadvantages of technology for coaches
advantages:
1. enhanced analysis
2. improved training
3. injury prevention
4. improved tracking
5. remote coaching
6. precision training
disadvantages:
1. technical issues
2. dependency on technology
3. information overload
4. cost and accessibility
advantages and disadvantages of technology for performers
advantages:
1. performance enhancement
2. improved training feedback
3. injury prevention
4. motivation and engagement
disadvantages:
1. performance pressure
2. privacy concerns
3. overdependence
advantages and disadvantages of technology for officials
advantages:
1. enhanced decision making
2. increased communication
3. increased accuracy
4. training opportunities
5. increased transparency
disadvantages:
1. disruption of flow
2. controversy and interpretation
3. undermines official’s authority
4. cost and implementation challenges
advantages and disadvantages of technology for spectators
advantages:
1. enhanced viewing experience
2. increased engagement
3. access to information
disadvantages:
1. overcommercialisation
2. distraction
3. accessibility issues
