Lecture 23 - Analyzing Pushing

Question 1

define pushing movements

Answer 1

• all segments in the kinetic link chain moving together

Question 2

what are the goals of pushing movements?

Answer 2

1. maximizing the force at the end of the chain
2. maximizing the power (force and velocity) at the end of a chain
3. optimizing the accuracy of the motion or projectile

Question 3

how is maximizing force used?

Answer 3

• when a person is working against resistance
• largest force against the resistance
• speed doesn’t matter, just want enough force to perform the movement
• to maximize force you want to go slower (so the body isn’t worried about velocity)
• ex: weight lifting

Question 4

how is maximizing force measured?

Answer 4

• performance is measured by peak force
• rectilinear motion (a straight line directly up) to maintain balance
• timing of the peak force and speed are not very important

Question 5

how is maximizing power used?

Answer 5

• force and velocity produced are both important
• few categories where this is important

Question 6

what are the 5 categories where power is important?

Answer 6

1. jumping and takeoff of aeriel events
2. race starts
3. punching and kicking
4. lifting
5. cyclic events

Question 7

how is maximizing power measured?

Answer 7

• performance is measured by the impulse of the force

Question 8

where does max power come from in jumping/takeoff?

Answer 8

• resistance comes from the inertia of the COG as it is accelerated upwards against gravity
• resistance also comes from resisting gravity and setting up the right angular momentum
• ex: high jump or vertical jump

Question 9

where does max power come from in race starts?

Answer 9

• resistance the inertia of the body resisting a horizontal acceleration
• starting blocks provide max amount of reaction you will be able to get –> during the sprint you rely on friction and the spike in the track
  ex: swimming or sprinting

Question 10

where does max power come from in punching?

Answer 10

• resistance is first the inertia of the arm and then the target
• ex: punching or kicking (same but with the foot)

Question 11

where does max power come from in lifting?

Answer 11

• resistance is the inertia of the weight against gravity and the need to accelerate it fast
• ex: clean and jerk, snatch

Question 12

where does max power come from in cyclic events?

Answer 12

• repeated pushes (or pulls) against resistance that repeats
• rowers negative push (pull) with their arms simultaneous to pushing with their legs
• ex: rowing

Question 13

how is the accuracy of motion or projectile optimized?

Answer 13

• push motions
• this sacrifices speed (but it will go in a straighter liner and it will be easier to predict where the ball will go)
• push ensures a rectilinear pathway with a greater margin of error
• margin of error is reduced with more speed
• ex: tennis serves, darts, volleyball setter