Lecture 22 - Pushing and Throwing

Question 1

what are the three overall performance objectives of throwing and pushing?

Answer 1

1. maximizing the horizontal distance of the object
2. maximizing the vertical distance of the object
3. accurately projecting the object (could be maximizing speed/spin)

Question 2

define a movement pattern

Answer 2

• a combination of motions at several joints

Question 3

define skill

Answer 3

• when the movement pattern is a well-defined activity or for a sport

Question 4

what are the three types of constraints placed on throwing and pushing skills?

Answer 4

1. size, weight, nature of the projectile
2. size, distance, nature of target
3. limitations of the way the throw or push can be performed

Question 5

define open skill

Answer 5

• the motion and environment are unpredictable

Question 6

define closed skill

Answer 6

• the motion and environment are predictable and under your control

Question 7

define open kinetic chain

Answer 7

• the end of the moving chain of segments is free to move (translate and rotate)

Question 8

define closed kinetic chain

Answer 8

• the end of the moving chain of segments is constrained

Question 9

what type of kinetic chain is a throwing movement?

Answer 9

• open kinetic chain

Question 10

what type of kinetic chain is a pushing movement?

Answer 10

• closed kinetic chain

Question 11

define sequencing

Answer 11

• the timing of motion of each segment
• the sequence of segments is critical

Question 12

what is the radius when dealing with an open kinetic chain?

Answer 12

• radius of rotation

Question 13

what are the characteristics of the radius of rotation?

Answer 13

• the further the segment is from the axis of rotation, the larger the radius of rotation and the faster its linear velocity

Question 14

how do you calculate the linear velocity of an object?

Answer 14

• V = rw
• velocity = radius x radians per second

Question 15

what are the three general rules of a kinetic link system for throwing?

Answer 15

1. the system has a base
2. the more massive segments are closest to the base, less massive further from the base
3. segments closest to the base move first, segment furthest from the base move last

Question 16

what is the goal for kinetic link systems for throwing?

Answer 16

• to maximize speed at the end of the chain

Question 17

what type of motions occur at joints?

Answer 17

• lever motions

Question 18

what are wheel-axle motions?

Answer 18

• a subset of segment motions that occur about the long axis of the segment
• generally any motion that is internal or external rotation

Question 19

what is the goal of a pushing sequence?

Answer 19

• to maximize the force at the end of the chain
• segments for pushing is generally all at once

Question 20

why do beginners in sports tend to use push > throw?

Answer 20

• push is more accurate
• push tends to be slower
• throw tends to have more speed and power

Question 21

how is the distance from the base affected by the size/weight of the object being thrown/pushed?

Answer 21

• distance from the base is increased when an object is lighter
• therefore the further from the base of the kinetic link chain they can get
• for example: pitchers throw baseballs at a very large angle in comparison to where the ball is held during shotput