Age to Teach the Curve Ball; How to Teach it, and
Common Faults that Add Stress on the Pitching Arm
Coach Bill Thurston
I. When to Teach the Curve Ball
Of course a lot depends on the physical development of a young
pitcher, but generally speaking, I believe a pitcher should be
close to 15 years of age before throwing the curve ball in game
situations. It is not a matter of being able to teach the pitch
to a young pitcher, but rather should it be taught to pitchers
with immature arms?
Factors to consider:
Has the pitcher reached puberty; how developed are his bones and
- A young pitcher’s connective tissues, his tendons and
ligaments, are not as strong or as securely attached compared to
a mature pitcher, thus there is a greater risk of injury.
Is the pitcher in the middle of a major growth spurt?
How well developed are the biceps, triceps and forearm muscles?
- A young pitcher needs arm muscle strength to help stabilize and
control the forces on the elbow joint during the acceleration,
release and deceleration phases.
Has the pitcher been taught to throw the curve ball properly?
How many curve balls (percentage wise) is he throwing in games?
Is the pitcher experiencing any arm, mainly elbow, problems from
throwing the curve ball?
Most of the stress from throwing the curve ball is on the
ligaments of the elbow, the biceps and forearm muscles. Since the
hand and arm speed is slower than on the fastball and slider, and
the elbow leads longer, there is usually not as much stress on
the shoulder joint as on the fastball.
Another major reason I have concerns about teaching the curve
ball to 13 and 14-year old pitchers is that they already have
more than enough physical stress having to pitch from a 60’ 6’’
mound versus the 46 foot Little League distance. To add a
breaking pitch at this age only compounds the physical exertion
on the arm and body.
Most young pitchers' hands and fingers are smaller and shorter,
so the youngsters have problems gripping, controlling and
releasing the pitch properly. This often causes the hand, wrist
or elbow to be out of proper position during the acceleration and
release phases, which can lead to injury.
Also, when a young pitcher learns to throw a curve ball and has
some success with it, he often “falls in love” with the pitch
(throws it too often) and he will never really develop arm
strength, hand speed, and fast ball velocity.
II. How to Teach the Curve Ball
The following is a curve ball drill sequence that I use to teach
and re-enforce proper techniques to throw the curve ball. Notice
the ball is thrown from short distances and slow speeds. The
purpose is to teach the pitcher proper techniques and develop the
proper feel of the pitch without creating stress on the throwing
Curve Ball Drill Sequence
A. Grip: We teach a four (4) seam grip with the middle finger
pressed up against a long seam. The thumb should be placed under
the ball (and middle finger) with the inside ridge of the thumb
contacting the ball. Do not choke the ball so deep that the thumb
cannot flick up behind the ball during the release phase. There
should be a space between the thumb and first finger. The
pressure points on the curve ball should be: the outside of the
middle finger against the seam, the ball stabilized between the
1st and 2nd joint of the ring finger, and the inside of the
thumb. The first finger is relaxed and up against the middle
The grip needs to be firm, but the wrist and forearm muscles
should be relaxed so the muscles can forcefully contract during
the release phase.
B. Hand separation and arm path to the cocked position: Break
down, back, and up keeping the fingers and hand on top of the
ball, exactly the same as on the fastball except for the grip.
C. Cocked position: RHP. (Mirror or partner check)
Palm of the hand faces the shortstop
Wrist extended back
Elbow shoulder height, hand head high
Firm grip but a loose wrist and forearm
Hand closer to 3rd base than the elbow for a RHP; hand outside
(back beyond) the elbow.
Lead elbow up to shoulder height, aligned to the plate (use
front elbow as a rifle site), keeping the front side closed as
long as possible.
D. Trunk Rotation Drill: (Mirror or Partner check)
Start in a proper cocked position.
On “now”, rotate and square the trunk (hips and shoulders) to the
To rotate trunk
(1) Drive the lead elbow downward to a position outside the
lead hip and close to the body.
(2) At the same time, roll the pivot foot over to release the
back hip squaring the torso to the plate and begin bracing the
stride leg. Stop in a squared position to home plate.
a. Shoulders should be relatively level
b. The palm of the pitching hand should face the head (turned
c. Fingers on top of the ball
d. Wrist in an upright neutral position
e. Pitching elbow aligned with the shoulders but with the
elbow leading the hand a little longer than on the fastball.
E. Spinning (throwing) the curve ball
From the cocked position, rotate the trunk, and lob (spin) the
curve down and away.
Develop the feel, muscle memory, of the fingers coming down
over the top outside of the ball (1 to 2 o’clock) and the thumb
flicking up - through the back of the ball creating a fast
The wrist snaps forward and inward and the ball spins out over
the middle finger.
After ball release, relax the arm to allow for the natural arm
pronation, and then bring the hand diagonally downward across the
body with the hand decelerating down and outside the knee of the
braced stride leg. Flex forward from the waist during the release
phase getting the head and shoulders over the stride leg. Throw
(lob) the ball from a 25-30 foot distance to learn the feel.
F. Next drill, down, back and up, Hesitate, throw.
Start with the hands together under the chin, feet in a wide
stride position, stride foot open. On a cadence from a coach or
partner, break down back and up, stop for 1-2 seconds to check
the cocked position. Then spin the curve at 35-40 feet.
G. Next sequence, down, back and up, throw – no hesitation. Pull
the back knee forward and inward, bringing the backside into the
pitch. Work on the proper arm action and develop a feel of the
release. Work for a ball rotation of a 45 degree angle down and
away from the arm side. Emphasize forward torso flexion during
the release phase.
(RHP – 1-7 or 2-8 o’clock – 35-40 foot distance)
H. Final sequence, curve ball from the Set Position
(50-52 feet, ¾ speed)
Via high speed video, we have observed that pitchers with
outstanding curve balls:
1. Have the hand high in the cocked position (elbow shoulder
height) so they can throw in a downward plane.
2. Get their trunk squared to the plate during the
3. Have a loose wrist that snaps downward and inward right
after ball release.
4. Bring the head and throwing shoulder down over and outside
a braced stride leg more forcefully than on the fastball (forward
III. Common Mechanical Faults Throwing the Curve Ball
A. Faults that add stress on the arm
1. Twisting action of the wrist and hand during the release
2. Attempting to create a 12-6 ball rotation by snapping the
hand and wrist straight down during the release phase
(hyper-extends the elbow).
3. During release, the hand and fingers roll under the ball.
The elbow and forearm drops low causing too much extension of the
4. Elevates the elbow during the acceleration phase. The
pitcher tries to throw too much over the top which overly extends
the elbow. This also may cause impingement in the shoulder joint
or cause bicep tendonitis.
5. Hand and elbow too low in the cocked position. The arm
accelerates upward causing an upward casting of the ball versus
the hand accelerating forward.
6. Pitcher has not stretched and warmed up properly.
The most important technique to emphasize on all pitches is the
position of the wrist at the point of release. This is much more
important then the grip on the ball.
B. Other common technique faults
1. Grips the ball too deep (“chokes the ball”), which reduces
ball rotation. Also, the thumb is placed on the side of the ball
versus under the ball.
2. Grips the ball too loosely. The ball slips out, reducing
rotation and causes control problems.
3. Cups the wrist (inward flexion) during arm acceleration
and the release phase, reducing pitch velocity.
4. Front side flies open early causing the throwing arm to
drag and get too low.
5. Starts to flex forward before the trunk squares to the
6. Not focusing on specific spots. Think “curve ball for a
strike” or “curve ball for an out” (2 strikes on batter; start
the pitch in the strike zone and break it down and away).
Note: When working on the curve ball at a normal distance and
velocity, a pitcher should not throw over 5-6 curves in a row.
The forearm flexor muscles tend to fatigue quickly. Throw one or
two fastballs for arm muscle extension then go back to the curve.
If older and experienced pitchers have an effective curve ball
using their own unique grip and motion, do not attempt to change
1. They are experiencing elbow or forearm problems, or
2. They cannot control the pitch.
Bill Thurston has been at Amherst College in Massachusetts for
37 years and has won nearly 65% of all games played (667-389).
Since 1990, Thurston has served as the pitching consultant for
the American Sports Medicine Institute in Birmingham, Alabama.
Bill has conducted baseball clinics in over 25 states and five
provinces of Canada and was inducted into the American Baseball
Coaches Association Hall of Fame in 1997. He was a standout
player at the University of Michigan and later served as the NCAA
Baseball Rules Editor for 14 years. He is a nationally known
clinic speaker, and many of his instructional materials have been
published and videotaped