Editing Knuckleball (section)

==Grip and motion==
[[Image:EddieCicotte55.jpg|right|thumb|167px|[[Eddie Cicotte]], who is sometimes credited with inventing the knuckleball]]
As used by Cicotte, the knuckleball was originally thrown by holding the ball with the [[knuckle]]s, hence the name of the pitch. [[Ed Summers]], an Indianapolis teammate of Cicotte who adopted the pitch and helped develop it, modified it by holding the ball with his fingertips and using the [[thumb]] for balance, contrary to the misnomer that the ball is being held with the knuckles.<ref>{{Cite news |last=Johnson |first=David |date=June 6, 1986 |title=Richards' Elephant Mitt Fit Wilhelm's Knuckleball Like a Glove |url=https://www.chicagotribune.com/1986/06/06/richards-elephant-mitt-fit-wilhelms-knuckleball-like-a-glove/ |access-date=June 25, 2024 |work=[[Chicago Tribune]]}}</ref><ref>{{Cite news |date=September 19, 2012 |title=Mets' Pitcher Makes 'Knuckleball!' His Own |url=https://www.npr.org/2012/09/19/161424002/mets-pitcher-makes-knuckleball-his-own |access-date=June 25, 2024 |work=[[NPR]]}}</ref> This grip can also include digging the [[fingernail]]s into the surface of the ball. The fingertip grip is more commonly used by modern knuckleball pitchers, like the Boston Red Sox pitcher [[Tim Wakefield]], who had a knuckleball with a lot of movement. There are other prominent knuckleball pitchers like Hall of Famer [[Phil Niekro]], who had a very effective knuckler and knuckle curve, and [[Cy Young Award]] winning pitcher [[R. A. Dickey]]. However, young pitchers with smaller hands tend to throw the knuckleball with their knuckles. Sometimes young players will throw the knuckleball with their knuckles flat against the ball, giving it less spin but also making it difficult to throw any significant distance.

Regardless of how the ball is gripped, the purpose of the knuckleball is to have the least possible amount of rotational spin. When thrown that way, the ball's [[trajectory]] is significantly affected by variations in airflow caused by differences between the smooth surface of the ball and the stitching of its seams. The asymmetric [[drag (physics)|drag]] that results tends to deflect the trajectory toward the side with the stitches.

Over the distance from the [[pitcher's mound]] to [[home plate]], the effect of these forces is that the knuckleball can flutter, dance, jiggle, or curve in two different directions during its flight. A pitch thrown entirely without spin is less desirable, however, than one with a very slight spin. If the ball completes between one-quarter and one-half a rotation on its way from the pitcher to the batter; the position of the stitches changes as the ball travels, affecting the drag that gives the ball its motion, thus making its flight erratic. Even a ball thrown without rotation will "flutter", due to the "apparent wind" it feels as its trajectory changes throughout its flight path.<ref>{{cite web|url=http://baseball.physics.illinois.edu/knuckleball.html |title=The Physics of Baseball: Knuckleball Research |first=Alan M. |last=Nathan |access-date=2014-09-18}}</ref>

Hitting a knuckleball is different enough from other aspects of baseball that players specifically prepare for the pitch during batting practice before games they expect it in.<ref name="reddit20121221">{{cite web | url=https://www.reddit.com/r/IAmA/comments/158o2d/i_am_2time_nl_mvp_dale_murphy_former_mlb_player/?limit=1500 | title=I am 2-time NL MVP Dale Murphy, former MLB player for the Braves, Phillies and Rockies. AMA! | work=Reddit | date=2012-12-21 | access-date=December 21, 2012 | author=Murphy, Dave}}</ref> According to physicist [[Robert Adair (physicist)|Robert Adair]], due to the physiological limitation of human [[reaction time]], a [[breaking pitch|breaking]] knuckleball may be impossible to hit except by luck.{{r|newyorker}} If a knuckleball does not change direction in mid-flight, however, then it is easy to hit due to its lack of speed. (A common phrase for hitting a knuckleball is "if it's low, let it go; if it's high, let it fly"; meaning that a batter should attempt to hit a knuckleball only if it crosses the plate high in the strike zone due to lack of break.) Since it typically only travels {{Convert|60|to|70|mph|km/h}},<ref>{{cite news|url=http://mlb.sbnation.com/2012/6/24/3112079/ra-dickey-knuckleball-fast-power-mets|title=Will R. A. Dickey's Angry Knuckleball Change The Game?|work=Baseball Nation|date=June 24, 2012|access-date=June 29, 2012|author=Neyer, Rob}}</ref> far slower than the average major league fastball {{Convert|85|to|95|mph|km/h}}, it can be hit very hard if there is no movement. One 2007 study offered evidence for this conclusion.<ref>{{cite web|url=http://www.hardballtimes.com/main/article/butterflies-are-not-bullets/|title=Butterflies are not bullets|last=Walsh|first=John|date=November 27, 2007|work=The Hardball Times|access-date=31 October 2012}}</ref> To reduce the chances of having the knuckleball get hit for a [[home run]], some pitchers will impart a slight [[topspin]] so that if no force causes the ball to dance, it will move downward in flight. Another drawback is that runners on base can usually advance more easily than if a conventional pitcher is on the mound. This is due to both the knuckleball's low average speed and its erratic movement, which force the catcher to keep focusing on the ball even after the runners attempt to [[Stolen base|steal]] a base. However, since a typical major league starting rotation exceeds the length of a series against any one opponent, one way a manager can mitigate this disadvantage is to adjust his team's pitching rotation so as to eliminate (or at least minimize) games in which a knuckleballer would pitch against teams with a preponderance of fast baserunners.

A paper presented at the 2012 Conference of the International Sports Engineering Association argues, based on [[PITCHf/x]] data, that knuckleballs do not make large and abrupt changes in their trajectories on the way to home plate—or at least, no more abrupt than a normal pitch. It speculates that the appearance of abrupt shifting may be due to the ''unpredictability'' of the changes in direction.<ref>{{cite journal|last=Nathan|first=Alan M.|date=February 29, 2012|title=Analysis of knuckleball trajectories|journal=Procedia Engineering|volume=34|pages=116–121|doi=10.1016/j.proeng.2012.04.021|doi-access=free}}</ref>