© 2008 McGraw-Hill Higher Education. All Rights Reserved. Chapter 18: Moving Objects: Throwing, Striking, and Kicking KINESIOLOGY Scientific Basis of Human

© 2008 McGraw-Hill Higher Education. All Rights Reserved.

Chapter 18:Chapter 18:Moving Objects:Moving Objects:Throwing, Striking, and Throwing, Striking, and KickingKicking

KINESIOLOGYScientific Basis of Human Motion, 11th edition

Hamilton, Weimar & Luttgens

Presentation Created byTK Koesterer, Ph.D., ATCHumboldt State University

Revised by Hamilton & Weimar

KINESIOLOGYScientific Basis of Human Motion, 11th edition

Hamilton, Weimar & Luttgens

Presentation Created byTK Koesterer, Ph.D., ATCHumboldt State University

Revised by Hamilton & Weimar


ObjectivesObjectives

1. Classify activities involving throwing, kicking, or striking patterns according to the nature of the force application.

2. Name and discuss anatomical and mechanical factors that apply to throwing, kicking, or striking activities.

3. Perform a kinesiological analysis of a sequential throwing, kicking, or striking skill under each of these force application conditions: momentary contact; projection; continuous application.


SEQUENTIAL MOVEMENTSSEQUENTIAL MOVEMENTS

Movement of body segments resulting in the production of summated velocity at the end of the chain of segments.

Path produced is curvilinear. Most frequently used to produce high

velocities in external objects. Depending on objective of skill (speed,

accuracy, distance, or combination) modifications to pattern may be made.


Joint Action PatternsJoint Action Patterns

Each pattern involves a preparatory movement referred to as a backswing, or wind up.

This is followed by the establishment of a base of support prior to initiation of

Force phase Ending in a follow through.


Overarm PatternOverarm Pattern

Characterized by rotation of the shoulder joint.

Backswing: abducted arm rotates externally. Force phase: arm rotates internally.

Some elbow extension, wrist flexion, and spinal rotation.

Rotation of pelvis at the hip joint of opposite limb, resulting in internal rotation of the thigh.


Overarm PatternOverarm Pattern

Fig 18.2


Underarm PatternUnderarm Pattern

Consists of forward movement of extended arm.

Basic joint action is arm flexion.

Fig 18.4


Sidearm PatternSidearm Pattern

Basic movement is medial rotation of the pelvis on the opposite hip with the arm usually in an abducted position.

Arm is moved forward due to pelvic and spinal rotation.

Spine laterally flexes toward throwing arm. Elbow maintains or is extended slightly. Wrist flexion may also be part of the action.


Sidearm PatternSidearm Pattern

Fig 18.5


Kicking PatternKicking Pattern Is a modification of a locomotor pattern in

which force is imparted to an external object during forward swing of non-weight bearing limb.

Non-kicking foot is stabilized. Pelvis is fixed over thigh & rotated toward

support leg. Kicking leg lags behind; abduction &

hyperextension. Kicking leg flexes at hip followed by knee

extension.


Fig 18.6

Kicking PatternKicking Pattern


Nature of Force ApplicationNature of Force Application

Momentary Contact: striking and kicking. contact made with an object by a moving

body part or implement.

Projection: throwing an object is given some velocity and is

released at the desired point.


PRINCIPLES RELATING TO PRINCIPLES RELATING TO THROWING, STRIKING AND THROWING, STRIKING AND KICKINGKICKING

Anatomical Principles Muscles contract more forcefully if they are

first put on stretch. Unnecessary movements and tension mean

awkwardness and unnecessary fatigue. Skillful performance can be developed only

by practice of the technique. Most efficient type of movement is ballistic. Appropriate levers should be used for the

task.


Mechanical PrinciplesMechanical PrinciplesThrowingThrowing

1. The object will move only if the force is of sufficient magnitude to overcome the object’s inertia.

2. The pattern and range of joint movements depends on the purpose of the motion.

3. Force exerted by the body will be transferred to an external object in proportion to the effectiveness of the counterforce of the feet against the ground.



4. Linear velocity is imparted to external objects as a result of angular velocity of the body segments.

5. Optimum summation of internal force is needed if maximum force is to be applied to an object.

6. For a change in momentum to occur, force must be applied over time.



7. Force applied in line with an object’s center of gravity will result in linear motion of the object, provided it is freely movable.

8. If the force applied to a freely movable object is not in line with it’s center of gravity, it will result in rotary motion of the object.


Striking, Hitting, and Kicking Striking, Hitting, and Kicking

Major factors in the speed of a struck ball:

1. Speed of incoming ball & striking implement.

2. Mass of the ball & striking implement.

3. Elasticity between ball & striking implement.

4. Direction of ball & implement at impact.

5. Point of impact between ball & implement.


Mechanical PrinciplesMechanical PrinciplesStriking, Hitting, and KickingStriking, Hitting, and Kicking

1. The direction in which the object moves is determined by direction of force applied.

2. Momentum is conserved in all collisions.3. Any change in momentum of colliding

objects is related to force and duration of collision.

4. The greater the velocity of the approaching ball, the greater the velocity of the ball in the opposite direction after it is struck.



5. The greater the velocity of the striking implement at the moment of contact, the greater the velocity of the struck ball.

6. The greater the mass of the ball, up to a point, the greater its velocity after being struck.

7. The greater the mass of the striking implement, up to a point, the greater the striking force, and hence the greater the speed of the struck ball.



8. The higher the coefficient of restitution (elasticity) of the ball and of the striking implement, the greater the speed of the struck ball.

9. The direction taken by the struck ball is determined by four factors:

1. Direction of striking implement at contact; 2. Relation of the striking force to ball’s center of

gravity; 3. Degree of firmness of grip and wrist at contact; 4. Laws of rebound.


EXAMPLES OF THROWING EXAMPLES OF THROWING AND STRIKINGAND STRIKING

Analysis of the Overarm Throw This analysis includes joint actions,

muscle activity, and mechanics of the upper extremity only.


Analysis of the Overarm Analysis of the Overarm ThrowThrow

Backswing The purpose is to place joints in optimal

position and involve the greatest number of segments in preparation for the force phase.

Includes pelvic and trunk rotation in the opposite direction, horizontal abduction and lateral rotation at shoulder joint with elbow flexion and wrist hyperextension.

A forward step is taken with the opposite foot, permits greatest ROM in trunk and pelvis, and a large base of support.


Analysis of the Overarm Analysis of the Overarm ThrowThrowForce Phase Immediately following establishment of a base

of support, pelvis and then trunk rotation are accompanied by lateral flexion to the left.

Trunk motion causes increased horizontal abduction with continuing lateral rotation at the shoulder joint.

Elbow extension is followed by rapid medial rotation at shoulder, forearm pronation, and then flexion and ulnar deviation at wrist.

Ends with release of the ball.



Follow-through From ball release until the momentum in

the arm can be safely dissipated as the arm continues across the body in a downward direction.

A forward step is also used.



Actions proceed from proximal (more massive) to distal (lighter) segments.

Momentum is transferred from more massive (proximal) to less massive (distal) segments, significantly increasing their velocity.

Linear velocity at the end of the chain (ball at release) often can exceed 90 mph.

Legs provide the stable base, contribute significantly to force production and transfer of momentum.



Shoulder Joint Actions Lateral rotation preceding the medial rotation

is controlled by eccentric contraction of medial rotators followed by concentric contraction of the same medial rotators.

Height of humerus is controlled by static contraction of middle deltoid.

Deltoid & supraspinatous contract concentrically during backswing to position upper arm, and eccentrically during the follow-through to help decelerate the arm.



Other Muscles Involved Biceps has peak activity as the elbow is

flexed late into backswing, at the beginning of force phase, and again during follow-through.

Latissimus dorsi, active during medial rotation, remains active eccentrically during follow-through.

Trunk rotators are also active.



Stretch Reflex An important facilitating mechanism in

accelerating the lagging distal segments. The more rapid the stretch (eccentric

contraction), the greater will be the facilitating effect on the resulting concentric contraction of the same muscle.

Forces can be summated more appropriately.



Other Reflexes As the trunk rotates under the stationary head

(eyes focused on the target), tonic neck reflex may facilitate the strong acceleration occurring during the force phase. Asymmetric tonic neck reflex facilitates the shoulder

abductor and elbow extensors on the chin side, precisely the arm position at release.

Increasing pressure on the hand and weight transfer to forward foot may produce an extensor thrust reflex. Facilitation of the lower limb extensor muscles. Facilitation of arm extensors.


Analysis: Forehand Drive in Analysis: Forehand Drive in TennisTennis

Description Objective is to send

the ball over the net and deep into the opponent’s court close to the base line.

Fig 18.7


Analysis: Forehand Drive in Analysis: Forehand Drive in TennisTennis Starting Position: Player faces the net with

feet about shoulder width apart and the weight of the balls of the feet. Racket is held with an hand shake grip.

Backswing: Player pivots entire body so that the non-racket side is toward the net.

Racket is taken back at shoulder level, with head of racket above the wrist and the face turned slightly down.

Players’ weight is over the rear foot.


Analysis: Forehand Drive in Analysis: Forehand Drive in TennisTennisForward Swing Player flexes at the knees to drop racket

below intended contact point, keeping racket head above the wrist.

Steps toward the ball with non-racket foot. Pelvis and spine rotate so trunk faces

forward, and weight is shifted to forward foot as racket is swung forward and up.

Racket face is perpendicular to court at ball impact, imparting topspin to the ball.


Analysis: Analysis: Forehand Drive in TennisForehand Drive in Tennis

Follow-Through Follow-through continues toward the

intended target, with the racket arm swinging across the body and up.


Analysis: Forehand Drive in Analysis: Forehand Drive in TennisTennisAnatomical Factors Action is ballistic in nature. Initiated by muscular force, continued by

momentum, and finally terminated by the contraction of antagonistic muscles.

Chief levers: arm, trunk, and racket. Fulcrum: at opposite hip joint. Point of force application: at a point of the

pelvis representing combined forces of the muscles producing the movement.


Analysis: Forehand Drive in Analysis: Forehand Drive in TennisTennisAnatomical Factors Resistance application point: at the center of

gravity of the trunk-arm-racket lever. May be considered the point of contact with the

ball at the moment of impact. Additional lever actions due to rotation of the

spine, horizontal adduction at shoulder, and flexion at wrist.

Muscular Strength: shoulder abductors assisting with swing, & rotators of spine and pelvis.


Analysis: Forehand Drive in Analysis: Forehand Drive in TennisTennisMechanical Analysis Purpose is to return ball in the court, but also

to make it difficult to return. Requires both high speed and accuracy. Force of impact: speed of racket at moment of

contact. Straight backswing: ease of control, but must

overcome inertia. Circular backswing: greater distance to build

momentum.



Mechanical Analysis Arm fully extended to increase lever length. Effort to resist force of ball is less when the

racket lever arm is shortened. Take less time to swing a shortened racket

lever into position. Concentration of mass at shoulder level

moving forward at impact ensures maximum speed of striking.



Mechanical Analysis Skillful players use a heavier racket - greater

mass of implement greater striking force. A new ball and well strung racket ensure

good coefficient of restitution (elasticity). Shift weight while striking the ball to

increase ground reaction force imparted to body & ball.

Firm wrist and grip are essential for maximum impulse to be applied by the racket to the ball.



Mechanical Analysis9. Direction of struck ball is determined

by:a) Direction of implement at impact.b) Relation of striking force to ball’s center

of gravity, control of spin.c) Firmness of grip and wrist at impact.d) Angle of incidence.


Chapter 18:Chapter 18:Moving Objects:Moving Objects:Throwing, Striking, and KickingThrowing, Striking, and Kicking

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© 2008 McGraw-Hill Higher Education. All Rights Reserved. Chapter 18: Moving Objects: Throwing, Striking, and Kicking KINESIOLOGY Scientific Basis of Human