Athletics- jumping

Question 1

Define projectile motion

Answer 1

Motion of object under influence of gravity and air resistance
Neglecting air resistance, constant horizontal velocity, changing horizontal velocity

Question 2

Angles for maximising the range of a projectile

Answer 2

Please height same as landing: optimum is 45 degrees
Release height less than landing: optimum greater than 45 degrees
Release height greater than landing: optimum less than 45 degrees

Question 3

Projectie motion- newtons 1st law

Answer 3

When no forces act on a body/net force is 0, body’s motion remains unchanged
Internal forces don’t change centre of gravity motion
path is predetermined before jump

Question 4

Centre of gravity

Answer 4

Although path of centre of gravity can’t be altered in flight, internal forces may be used to change mass distribution (position of segments) with respect to centre of gravity

Question 5

High jump- contributions to height

Answer 5

Raise centre of mass at take off
High arms
High lead leg
Fully extended take off leg

Question 6

Countermovement action (second to last step before hit the ground)

Answer 6

CM action stimulates stretch shortening action muscles. Pre stretching muscle with eccentric contraction before it is shortened increases the force the muscle can produce
CM also increases vertical ROM
Therefore the athlete has more time to apply force and increase impulse

Question 7

Increasing height of CM at TO and peak height of CM during flight

Answer 7

‘Trade off’ between size of fore and time of application. Athletes may not be able to apply max force if time is too short/long (due to muscle contractile properties and limb range of motion)
Arm swing- might help increase ground reaction force and body momentum during take off (larger force applied to the ground. ground will push you with longer force)
Performance improves with fast run up and application of large ground reaction force

Question 8

Long jump- take off distance

Answer 8

Accuracy of take off (close to the board)

centre of ass forward of the body

Question 9

Long jump- flight distance

Answer 9

Take off speed as fast as possible

lower CM at second to last stride and focus on upward movement on last step

Question 10

Long jump- touch down distance

Answer 10

land with CM behind feet and as low as possible
Feet as far forward as possible
Low knees
Flex hips, extend knees