Throwing Phases

7/29/2019 Throwing Phases

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2013


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Flexion - Extension

Abduction - Adduction

Medial and lateral rotation

(Internal and external rotation)

Transverse abduction - adduction


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6 main phases

I. Wind upII. Early cocking

III. Late cocking

IV. Acceleration

V. DecelerationVI. Follow-through


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Begins at the start of movement and ends whenthe lead leg is maximally lifted


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The coiling phase

Potential energy is developed

The center of gravity is raised

No appreciable stress on the shoulder and elbow


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front leg strides forward

trunk rotation

Center of gravity lowered

shoulder abducted to 90,shoulder ext rotation,

scapular retraction, andelbow flexion


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The four rotator cuff musclesfire to hold the head of thehumerus within the glenoidfossa.

Deltoid and supraspinatusproduce abduction

Infraspinatus and teres minorinitiate external rotation andassist abduction

trapezius and rhomboids retractthe scapula

EMG : Early Deltoid, Late Cuff


8/23

This phase begins when the lead foot makes contact with the

ground during the stride phase (early cocking ) and ends when thethrowing arm achieves its maximum external rotation

Rotation of the hips and pelvis helps set up the rotation that willbe transferred to the torso and shoulders.

Muscles acting at the shoulder and scapula position the glenoidfossa against the head of the humerus and stabilize the scapula.

Specifically these include the levator scapula, serratus anterior,

rhomboids, trapezius, and pectoralis minor.


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The rotator cuff muscles maintain tension at this point

to keep the head of the humerus stable

inside the glenoid fossa.

The internal rotators of the shoulder

will develop tension to slow down

and prevent excessive external rotation.


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external rotation -EXTREME

external rotationterminated by forces

from anterior joint capsule

& ligaments

subscapularis

pectoralis major

triceps brachii teres major

latissimus dorsi


12/23

common injuriesresulting fromEXTREME externalrotation

tendinitis ofsupraspinatustendon

muscle strain ofpectoralis major,teres major, orlatissimus dorsi


13/23

This is the quickest phase of the throw.

Starts just after the shoulder reaches maximumexternal rotation and ends when the ball is released.

The internal rotators of the shoulder have beenstretched like a coiled spring during the previousphase. They shorten rapidly, assisted by this spring-like effect, and produce very rapid internal rotationof the shoulder.


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characterized by

initiation of elbowextension

shoulder internal rotation

maintenance of shoulder

abduction at 90

shoulder transverseabduction

scapular protraction

Humerus IR 100 deg / 0.5sec

Eccentric to concentricconversion

transverse abduction and

internal rotation subscapularis,

latissimus dorsi

teres major

pectoralis major

scapular protraction serratus anterior

elbow extension triceps brachii


15/23

Muscle contraction with movement

muscle shortens or lengthen

2 subtypes :

Concentric : The muscle shortens during the contraction

Tension Applied load

Eccentric : The muscle lengthen during contraction


16/23

Starts when the ball is released and ends when

maximum internal rotation of the shoulder isreached.

The throwing arm is horizontally adducted andinternally rotated to the neutral or anatomical

position and the scapula is protracted. Posterior muscles of the G-H Joint, especially

the Teres Minor, slow down the movement atthe shoulder while the retractors of the scapula

slow down the scapular protraction.


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Begins when when the internal rotation of the

shoulder ends and finishes when the throwerreturns to a balanced position.

The arm deceleration process helps reduce theforce and therefore the stress on the joints andmuscles involved


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This part of the movement is designed to extendthe time that it takes to come to a stop as well asdistribute the forces to the body and leg.

The posterior muscles of the G-H Joint are very

important to continue the deceleration processat the shoulder.

The serratus anterior is very active in stabilizingscapular rotation while the rhomboids and the

middle part of the trapezius continue to slowdown and reduce the force of scapularprotraction.


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Throwing Phases