THE ANGLE OF PRONATION

By Dr. John Bagonzi

I must say at the beginning of this discussion that I did teach anatomy and physiology and also biology, but I make no attempt to turn this into a scientific essay. It is hardly intended to be a lesson in anatomical terminology. It does seem as though some simple, but not oft used terms "fit the bill" better sometimes or even the majority of moments, but in this instance I’m going to deviate and utilize a little anatomy and its mysterious world of words. However, I find that if we use them once and try to get over it quickly, that the discussion will be revealing without being confusing. It certainly is not an attempt to impress a scholarly dimension to explain something that may be quite simple (however often overlooked). But in the interest of brevity and simplicity in this discussion the anatomical terms will be utilized carefully at the outset and then eventually relegated to the vocabulary file.

In discussing the pronation phenomenon, it behooves one to understand that there are pitchers that do this well and have little or no understanding of this event. However, there are more than a substantial number that have bland, even weak fastballs, because they don’t execute the pronation concept correctly or at all. Being aware of the pronation angle and executing it creates a strong possibility of having movement on the fastball. This will create a positive situation for someone developing his fastball. It is also a great negative if this isn’t executed well or at all. The purpose here therefore is to discuss this occurrence.

PRONATION AND SUPINATION

Many persons are befuddled by words like pronation and supination and yet these catch-all words solve a myriad of concepts when applied to certain critical events in the pitching process. Pronation is talked about, few have a fix on it, but successful pitchers do it well and those with moving fastballs do it well.

Many pitchers particularly right-handed ones find themselves at key points in their development without any movement on their fastballs. This is without a doubt the critical character, which if missing (movement on fastball) may forfeit the pitcher’s stature as a prospect. Ultimately, velocity alone cannot do the trick. However, those few that marry velocity and movement bring about an effective fastball that emerges which can carry a career a long way. One should do all he can to establish a correct way of throwing a ball so that it possesses vitality and character. This involves understanding the concept of pronation and the angles necessary to achieve such.

EXTENT OF PRONATION

Certainly the amount of pronation has to be controlled—one would not want as much pronation as warranted on a screwball.

MUSCLES AND BONES OF THE FOREARM

There are two muscles in the forearm which are mainly involved in the pronation/supination process and they are the Pronator Teres and the Supinator Brevis. The bones involved are the radius and the ulna. In pronation the radius is rotated diagonally across the ulna and the palm faces dorsal (back) ward. In supination the radius and ulna are parallel.

Suffice it to say on pronation in the throwing of a baseball the thumb will move to the pitching side—to the right for a RHP and to the left for a LHP. In supination the thumb will turn in toward the glove side-to the left for a RHP and to the right for a LHP.

Pronation should happen on all thrown balls that are not designed to be curveballs, sliders, slurves or cutters.

ARM ANGLES AND PRONATION

Certainly arm deliveries and angles favor early pronation whereas others (overhand) favor late pronation. Anyone with a penchant for a sinking fastball probably pronates early and is likely a ¾ arm thrower.

ARM ANGLE	PRONATION EFFECT
Overhand	Late, mostly at release
Overhand Plus	Medium
Three-Quarter	Early—thumb to SS (for RHP)
Three-Quarter Minus	Quite early—thumb to 3rd (for RHP)
Sidearm	Early—Already pronated.

EARLY VS LATE PRONATION

The more one comes to a 2-8 type of rotation, the more one is likely to pronate early. By contrast, those with overhand deliveries in which the ball is thrown hard because the fingers are on top of the ball and the thumb is in a straight alignment, the pronation is likely just at release.

TYPE OF PITCHES INVOLVED WITH PRONATION AND SUPINATION

PRONATION	SUPINATION
Regular fastball	Curveball
Tailing or veering fastball	Slurve
Sinking fastball	Slider
Splitter	Cutter
Screwball	Knuckleball (on some types)
Change-up (Circle, OK, 3-Fingered)	Change-up (some types)
Shuuto—reverse slider	Splitter (some types)
Gyro ball—reverse slider (??)

Obviously some specialty pitches can be thrown with either a pronated effect or with a supinated effect and be effective either way. That is, a change-up could be pronated and have a movement away from a LHB or if it were supinated it would move into a LHB. The same can be said of the splitter and also the knuckleball. However, the other specialty pitches-- curve, slider, cutter, screwball, sinker and tailing fastball—all require a precision that is relative specifically to pronation or relative specifically to supination.

THE SHUUTO AND GYROBALL—TWINS??

The shuuto and the gyro ball are pitches in baseball which haven’t been assimilated by the American baseball society yet, but have been popular in Japanese baseball pitching circles (the shuuto anyway, gyro still has a hung jury) for some time are in my opinion versions of a reverse slider. I have attempted to throw a reverse slider many years ago and surely understand the aerodynamics of it without mastering it. For those who put it in the change-up/screwball category I suspect their assumptions may be somewhat correct. Until I see the gyro fully exposed, I’m going to consider it in the laud of the pronators. If it is spiral on concept it is likely a reverse slider—some call this a screwball. Because it is likely off speed, some may call it a change-up, so obviously it takes on a coat of many colors. My colleague, Gary Garland with the Japan Baseball Circuit who has been a privy to Japanese baseball for a long time and is a baseball writer for the Japan Baseball Daily (newspaper) insists the shuuto and gyro ball are different pitches. I’m going to say the shuuto is a reverse slider and the gyro ball will have to remain on my back burner for a while, but we will be hearing about this soon enough and I’ll be toying with it as i perceive it.

EARLY PRONATION VS LATE PRONATION

EARLY PRONATION—involves the thumb at shortly after hi-cock position (RHP) pointing towards shortstop and as the release comes about, points towards third base.

LATE PRONATION—fingers at release are coming across the ball and thumb is in the general direction of third base line.

EARLY SUPINATION—fingers at hi-cock are starting to go toward 1^st base line or glove side on the classic curve.

LATE SUPINATION—on slider the thumb is pointing to glove side and on cutter the thumb is slightly to the left (RHP). These would be examples of late supination. It happens more toward release.

A reminder that pronation and supination are NOT complex concepts and if one looks closely at 1) arm slots 2) wrist slots and 3) release points—a lot about the pitch and its character are revealed. Persons who study or read the spin on a thrown ball—a lot about the angles of delivery can be noted.

DEFINED PRONATION—IT is a rotation of the forearm that moves to palm from an up position to a palm facing down position (muscles involved are the pronators quadratus and the pronators teres).

SUPINATION—is the opposite of pronation, the rotation of the forearm so that the palm faces up. (The muscle involved is the supinator muscle).

Suffice this definition and discussion is all we need to apply these events to the pitching process.

EARLY PRONATION	LATE PRONATION
Sinker	Regular FB
Screwball	Tailing or veering FB
Some Splitters	Some Splitters
Pronation Curve
Circle Change

EARLY SUPINATION	LATE SUPINATION
Curve	Hard Slider
Slurve	Cutter
Some Sliders

Fitting into either-or would be: Change-ups, splitters, forkballs and knucklers—which could involve pronation or supination depending on what the pitcher wants.

With the influx of Japanese pitchers we may have the shuuto and the gyroball as pitches that likely are in the pronation category.

I find quite intriguing the areas of pronation and supination as criteria for movement on pitches. This is another area for the aspiring pitcher who wants a precision approach to his pitching program. Being astute in this area promotes understanding of universal laws governing this great skill which requires constant refining. It doesn’t have to be so complex as to detract from its importance.

PITCHES INVOLVING PRONATION AND SUPINATION

PRONATION	SUPINATION
Fastball (with tail or veer)	Curve
Sinking Fastball	Slurve
Screwball	Slider
Splitter (sometimes)	Cutter
	Splitter (sometimes)
	Change-up (sometimes)

POSITION OF PALM AND THUMB IN PRONATION

FOR A RHP	FOR A LHP
Thumb-goes to right away from glove	Thumb is to left
Palm is turning down	Palm is turning down

POSITION OF PALM AND THUMB IN SUPINATION

FOR A RHP	FOR A LHP
Thumb to left—toward glove side	Thumb to right
Palm is turning up	Palm is turning up

Small degrees of each can be accomplished with finger pressure (which is another way to make the ball move).

index for pronation

middle for supination

The art form is getting the right amount and getting the axis tilt to fit the desired break.

Understanding these anatomical terms is a fairly simple affair allowing the pitcher to experiment.

PITCHING INSTRUCTION

Pitching instruction should minimize and simplify the aspects of wrist and hand involvement not only in types of fastballs, but in the great variety of breaking pitches.

It’s amazing to me that those with bland, straight fastballs have not arrived at the necessary "doctoring" to improve and magnify their key pitch (and yet I stayed this way most of my career).

It may be necessary to get a strong fix on the arm angles, wrist angles, pronation extent (early or late) to determine one’s "action" zone or pitch slot. This would be where the ball acts best. In this regard, learning the angle of pronation as an estimate concept and event can only refine one’s pitching process. There will be those that approach this situation naturally and need little or no instruction to implement this phenomenon. However, there will be many who will develop their pitching schematic with outstandingly good results by being aware and perceptive in the angles of pitching.

As a point of conclusion, it is necessary to understand what action on a fastball means. The same applies to breaking pitches also. While pronation as the main thrust on correct fastball throwing and supination is the main concept on breaking pitches, there are some slight exceptions when either can enhance a pitcher’s effectiveness. Movement on the ball is everything in the measurement of a pitcher’s effectiveness. Anything that can be advanced to improve this condition (lack of movement) should be looked at carefully and thoroughly. Talent is wonderful and is exalted and admired but there is a large majority group that needs "tweaking" to reach the next level.

Be sure to take a look at Dr. Bagonzi’s book The Act of Pitching, It is in all book stores and can be ordered online. Also check out www.pitchingprofessor.com for more info on pitching and new video clips.

SPIN DIRECTIONS AND PRONATION (RHP)

1/7: Slight pronation—late—tailing fastball

2/8: Spin direction early and greater pronation—sinking FB

3/9: Spin early—probably sidearm—screwball type of pitch.

BODY TYPES AND PRONATIONS

Short, stocky ala Mike Marshall. Probably ideal as Marshall was the best of them all.

Carn Hubbell—loose wrist, lanky—lived by the screwball

Valenzuela—stocky

All kinds of body types when it comes to angle pronation

PRONATION ANGLES (RHP)

Thumb towards 2B and CF

Thumb between CF and SS

Thumb toward 3B

PRONATION ANGLES (LHP)

Thumb towards CF

Thumb towards 2B

Thumb towards 1B

FAVORED ARM SLOTS

3/4 for 2/8 spin (RHP) and sinking FB

¾ + for 1/7 spin (RHP) and tailing FB

Overhand for 6/12 to 1/7 spin and tailing, rising FB

3/4 – for 2/8 and 3/9 spin—screwball and sinker

Sidearm for 3-9 spin—sinker and screwball

WRIST ANGLE (RHP)

1 o’clock favors 1/7 rotation

2 o’clock favors 2/8 rotation

LEFT HANDED WRIST ANGLES

11 o’clock favors 11/5 rotation

10 o’clock favors 10/4 rotation

PRONATION GUARANTEES a strong release of the ball.

 

WRIST ANGLE AND PRONATION (RHP)

Wrist and fingers at 1 o’clock—1/7 rotation and tailing FB

Wrist and fingers at 2 o’clock—2/8 rotation and sinking FB

Wrist and fingers at 3 o’clock—3/9 rotation and a screwball type of action (almost always sidearmer)

Note—a 3/9 rotation can be accomplished from a higher arm angle and would be the precursor for a screwball.

WRIST ANGLE AND PRONATION (LHP)

Wrist and fingers at 11 o’clock—11/5 rotation and tailing FB

Wrist and fingers at 10 o’clock—10/4 rotation and sinking FB

Wrist and fingers at 9 o’clock—9/3 rotation and screwball type of action (see above note)

A word about a screwball—this pitch comes in different degrees—it is basically a reverse curveball, but can be like a reverse slider and also can take on a downspin where in effect it is like a drop.

 

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