Swimming Flashcards
Name the qualitative analysis stages
Preparation, observation, evaluation, intervention
Swimming velocity
Product of stroke rate and stroke length
What is the problem with the swimming velocity definition
Only valid mid pool
Stroke rate (cycles/min)
Number of complete cycles of one arm in a minute
Stroke length (m/cycle)
Distance the swimmer moves forward during the stroke cycle
What do SR and SL depend on?
Swimming stroke
Race distance
Antropmetric characteristics
How do swimmers tend to increase their velocity?
Increase stoke rate, decrease stroke length
Drag
Acts along the direction of motion
Lift
Acts at right angles to the direction of motion (perpendicular to flow)
Propulsion
May be obtained by accelerating a mass of water opposite the swimming direction in accordance with Newton
Resistive forces
Motion of the body parts in the water which produce forces not in the desired direction
Total resistance
Sum of frictional ‘pressure’ and ‘wave’ contributions when swimming at a constant speed
time spent in turns
accounts for up to 1/3 of overall time
release velocity- why is the magnitude of force important?
newton’s 3rd law: for every action there is an equal and opposite reaction
The more force the swimmer exerts, the more force the blocks will apply back
release velocity- why is the duration of force application important?
newton’s 2nd law: forces cause acceleration
the mass is constant thus the final velocity of starts depends on both the magnitude and duration
What is the optimum release angle in swimming
less than 45 degrees
release height is greater than landing height
How much time does reaction time account to on the blocks
Almost 1/4
What is the base of support?
Area beneath and between the 2 segments in contact with the ground
How does the swimmer initiate movement on the blocks?
Move CM close to the perimeter of the base of support to disrupt equilibrium
Gliding depth
Deeper usually for breaststroke and early race
Better swimmers tend to gland for longer
Minimum depth should be 0.4m
Too deep will increase time back to the surface, too shallow will increase resistance caused by surface waves
Factors affecting release velocity
Magnitude of force
Duration force
Factors influencing time on blocks
body position/balance
reaction time
Factors affecting smoothness of entry
entry angle
body position
influencing factors underwater
gliding depth, streamlining, kick timing, timing of surfacing
Factors before the turn
approach velocity (swim fast until turn) approach distance
Factors during the turn
rotation time (keep to a minimum)
Forces applied on the wall (maximise force. Less than 90 degree knee angle might result in inefficient length for quads)
Push off angle
Minimise resistance impulse
Change in motion depends on the magnitude of net force and time
Minimise the magnitude of resistive forces (minimise cross sectional area of body segments, minimise speed of body segments, optimise alignment)
Minimise the time of the resistive forces
Maximise propulsive impulse
The change in motion depends on the magnitude of the net force and the time over which it acts
Minimise the magnitude of propulsive forces
Maximise the time of the propulsive forces
Maximise propelling limbs cross sectional area to flow
Optimise propelling limbs alignment and direction
