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The fastball is the most common type of pitch in baseball. Some "power pitchers," such as Nolan Ryan and Roger Clemens have thrown it at speeds of 95–106 mph (152.9–170.59 km/h) (officially) and up to 108.1 mph (174 km/h) (unofficially), relying purely on speed to prevent the ball from being hit. Others throw more slowly but put movement on the ball or throw it on the outside of the plate where the batter cannot easily reach it. The appearance of a faster pitch to the batter can sometimes be achieved by minimizing the batter's vision of the ball before its release. The result is known as an "exploding fastball": a pitch that seems to arrive at the plate quickly despite its low velocity. Fastballs are usually thrown with backspin, so that the Magnus effect creates an upward force on the ball, causing it to fall less rapidly than might be expected. A pitch on which this effect is most marked is often called a "rising fastball", as the ball appears to rise to the batter. Colloquially, use of the fastball is called throwing heat or putting steam on it, among many other variants.
Gripping the ball with the fingers across the wide part of the seam ("four-seam fastball") so that both the index finger and middle finger are touching two seams perpendicularly produces a straight pitch, gripping it across the narrow part ("two-seam fastball") so that both the index finger and middle finger are along a seam produces a sinking fastball, holding a four-seam fastball off-center ("cut fastball") imparts lateral movement to the fastball, and splitting the fingers along the seams ("split-finger fastball") produces a sinking action with a lateral break.
Four-seam fastball 
The four-seam fastball is the most common variant of the fastball.
The four-seam fastball is a pitch that is used often by the pitcher to get ahead in the count or when he needs to throw a strike. The type of fastball is intended to have minimal lateral movement, if any. It is most often the fastest pitch that a pitcher throws, with recorded top speeds in the 100+ mph range. The fastest pitch, recognized by MLB and not somebody's recollection, was on September 25, 2010 at Petco Park in San Diego by Cincinnati Reds left handed relief pitcher and now closer, Aroldis Chapman. It was clocked at 105.1 miles per hour.  April 19, 2011 Chapman lit up the stadium radar gun at 106 MPH. (For the record, the TV-reading had his pitch at 105 MPH, and the pitchF/X reading was actually 102.4 MPH.  There are two general ways to throw a four-seam fastball. The first and most traditional way is to find the horseshoe seam area, or the area where the seams are the farthest apart. Keeping those seams parallel to the body, the pitcher places his index and middle fingers perpendicular to them with the pads on the farthest seam from him. The thumb then rests underneath the ball about in the middle of the two fingers. With this grip, the thumb will generally have no seam to rest on.
Two-seam fastball 
A two-seam fastball, sometimes called a two-seamer, tailing fastball, running fastball, or sinker is another variant of the straight fastball.
The two-seam fastball is designed to have more movement than a four-seam fastball so that the batter cannot hit it hard, but it can be more difficult to master and control. Because of the deviation from the straight trajectory, the two-seam fastball is sometimes called a moving fastball.
The pitcher grabs a baseball and finds the area on it where the seams are the closest together, and puts his index and middle fingers on each of those seams. A sinker is a similar pitch thrown with almost the same grip, but with the thumb directly underneath the ball. Sinkers are also thrown slightly slower than two-seamers.
Each finger should be touching the seam from the pads or tips to almost the ball of each finger. The thumb should rest underneath the ball in the middle of those two fingers, finding the apex of the horseshoe part of the seam. The thumb needs to rest on that seam from the side to the middle of its pad. If you use your middle finger when you throw you get more whipping action making the pitch go around 10 mph faster.
This ball will tend to move for the pitcher a little bit depending on velocity, arm slot angle and pressure points of the fingers. Retired pitchers Greg Maddux and Pedro Martínez were known for their effective two-seamers.
Depending on the grip and pressure applied with the fingers, sometimes the two-seam fastball features more sink than lateral movement. Sinkerballers tend to induce a lot of ground ball outs. This is because hitters tend to swing over the ball due to the late downward movement, and thus, often end up beating the ball into the ground. Jake Westbrook of the St. Louis Cardinals, Fausto Carmona and Justin Masterson of the Cleveland Indians, Derek Lowe of the New York Yankees, Tim Hudson of the Atlanta Braves, Aaron Cook of the Colorado Rockies, Clay Buchholz of the Boston Red Sox, Roy Halladay of the Philadelphia Phillies, Chris Volstad of the Chicago Cubs, Trevor Cahill of the Arizona Diamondbacks and Bronson Arroyo of the Cincinnati Reds are well known for their sinkers, consistently ranking high in the league in ground ball-to-fly ball ratio.
Rising fastball 
The rising fastball is an effect perceived by batters, but is known to be a baseball myth. Some batters claim to have seen a "rising" fastball, which starts as a normal fastball, but as it approaches the plate it rises several inches and gains a burst of speed. Tom Seaver, Sandy Koufax, Dwight Gooden and Chan Ho Park were often described as the paramount pitchers with this kind of ball action.
Such a pitch is known to be beyond the capabilities of pitchers due to the very high backspin that would be required to overcome gravity with the Magnus effect. While not physically impossible (conservation of momentum is maintained through imparting the required opposing momentum to air, as an airplane does at takeoff), the amount of spin required is beyond the capabilities of a human arm. It has been explained as an optical illusion. What is likely happening is that the pitcher first throws a fastball at one speed, and then, using an identical arm motion, throws another fastball at a higher speed. The higher speed fastball arrives faster and sinks less due to its high speed. The added back-spin from the higher speed further decreases the amount of sink. When the pitch is thrown, the batter expects a fastball at the same speed, yet it arrives more quickly and at a higher level. The batter perceives it as a fastball which has risen and increased in speed. A switch from a two-seam to a four-seam fastball can enhance this effect.
This perception may also be created by a tall, hard-throwing pitcher who throws the ball from a higher release point on an elevated mound (the pitcher's rubber is ten inches above the field level). Factoring in the element of depth perception when the hitter watches the pitcher from sixty feet six inches away from the pitcher's mound, and the hitter perceives the pitcher's size and positioning on the mound to be less elevated than it actually is. Hence, to the hitter an overhand pitch will appear to be thrown at a hitter's shoulder level (or even belt level), as opposed to several inches above the hitter's head, from where the pitch is actually released from the pitcher's hand. This perception enhances the apparent "rising" motion of the fastball when the pitch passes the hitter at a higher level than where the hitter perceived the pitch to have left the pitcher's hand.
It is possible for a rising fastball to be thrown by a submarine pitcher because of the technique with which they throw the ball. Because they throw almost underhand with their knuckles near the dirt, the batter perceives the sensation of the ball going upward because of its low starting point and flight trajectory. This is not the traditional rising fastball batters believe they see. This type of movement is similar to a rising fastball in fast-pitch softball. Left-hander Sid Fernandez was known for throwing a rising fastball from a slightly "submarine" motion.
A cut fastball, or "cutter," is similar to a slider, but the pitcher tends to use a four-seam grip. The pitcher shifts the grip on a four-seamer (often by slightly rotating the thumb inwards and the two top fingers to the outside) to create more spin. This usually causes the pitch to shift inwards or outwards by a few inches, less than a typical slider, and often late. A cutter is effective for pitchers with a strong four-seamer since the grip and delivery look virtually identical. The unexpected motion will often fool batters into hitting the ball off-center, or missing it altogether.
Mariano Rivera, a relief pitcher for the New York Yankees, is a pitcher known for throwing a cutter. In his prime, Rivera could deliver late motion while throwing the ball around 95 mph. Brian Wilson of the San Francisco Giants also throws a cutter. Al Leiter rode his cutter to 162 career wins and a no-hitter. Roy Halladay of the Philadelphia Phillies also throws a cut fastball, but claims that overusing it has given him forearm trouble which may have prematurely ended Halladay's 2006 season due to forearm stiffness, since the grip causes more stress than a standard four-seamer. Yankee Andy Pettitte is another pitcher who throws the cutter. On a June 3, 2007 game against the Boston Red Sox, announcer Joe Morgan estimated that of Pettite's 87 pitches, 83 of them were cutters.
Split-finger fastball 
The split-finger fastball or "splitter," is truly an off-speed pitch rather than a type of fastball. Like the changeup, to which it is a close relative, it is thrown with the same arm motion as a normal fastball, but the adjusted grip causes it to behave quite differently. The ball does not have the characteristically tight spin of a fastball. The ball appears to tumble in a knuckleball-like fashion; but it is much faster than a knuckleball. The ball is gripped tightly with the index and middle finger "split" along the outside of the horseshoe seam. It is important that at least one finger is touching the seam, as the ability to control the release of the ball is derived from this contact. The release is the same as a fastball. A splitter will usually drop as it approaches the plate, and break to either the right or left. The forkball is a similar pitch, though it is slower and gripped with a more exaggerated split of the fingers. A pitcher generally needs long, flexible fingers to effectively throw this pitch. Due to similarities in speed and movement, some pitcher's split-finger fastballs are misconstrued as changeups.
When thrown correctly, the splitter places no more stress on the arm than the regular fastball. This is because the split-finger is thrown using the same mechanics as the fastball; the only difference is in the grip. The splitter's effectiveness is also increased when thrown mechanically the same as the fastball because the hitter generally picks up the movement later.
The split-finger is used currently by pitchers such as Dan Haren, Jonathan Papelbon, and J. J. Putz. Former players noted for use of the split-finger fastball include John Smoltz, Jack Morris, Mike Scott, Kazuhiro Sasaki, Bryan Harvey, Bruce Sutter, Roger Clemens, and Fred Breining.
The Incurve was a term used until about 1930 used to describe a simple fastball. As a curveball was often called an "outcurve," one might assume that an incurve is the opposite of a curveball, in other words, the modern screwball. However, this does not appear to be so, as cited by John McGraw.
- All balls that are twisted out of their natural course are called curves. The outcurve, the drop, down shoot, and so on, are simply a curve ball to the professional player. To us there is no such thing as an incurve. That is what we call a fastball. Of course, I am assuming the pitcher is right-handed. A so-called incurve is nothing more than a ball thrown in a natural way with great force. A ball thus thrown will naturally curve inward, to a certain extent.
Side-arm fastball 
A side-arm fast ball is thrown from an angle different from the normal one. It is at a lower angle and is thrown from the side, hence the name "side"-arm. It will have a sinking motion to the right if it is a right hand pitcher, or to the left if it is a left hand pitcher. It is usually slower than a normal four-seam fastball.
- "The Fastest Pitcher in Baseball History". Baseball Almanac, Inc. Retrieved 2007-08-10.
- Zack Hample (2007). Watching Baseball Smarter. Vintage Books/Random House (USA).
- Mcgraw, John (1995). My Thirty Years in Baseball. Lincoln: University of Nebraska Press. ISBN 0-8032-8139-0.