Varying Arm Slots in Pitching and Their Relation to Injury

Former Red Sox Pitcher Hideki Okajima³

In regards to pitching, there are an infinite number of arms slots that vary from pitcher to pitcher. An arm slot, as described by Matt Lentzner, is simply the arm angle that a pitcher uses when throwing a baseball.2 Despite the variability between pitchers, there is typically four common arm slots in which they use: the overhand, three-quarter, sidearm, and submarine arm slots.

The first being the overhand arm slot, in which the pitcher’s arm is perpendicular to the ground. An example of this, would be previous Boston Red Sox’s relief pitcher Hideki Okajima. Like you can see in the picture, Okajima’s arm is straight up at 12 o’clock, in relation to a clock, prior to the release of the baseball.

The second type of arm slot, is known as the three-quarter release. As shown by Cub's relief pitcher Aroldis Chapman, the arm is instead angled at 1:30, prior to release of the baseball. This arm slot, is considered the most common, with most major league pitchers falling somewhere between the overhand and three-quarters arm slot.2

Cub's Pitcher Aroldis Chapman²

White Sox Pitcher Chris Sale¹

The third type, known as the sidearm arm slot, is at a 3 o’clock position. Pitchers with this type of arm slot, may look like they throw across their body. A prime example of this, would be current Chicago White Sox ace, Chris Sale.

Finally, the last arm slot, is known as the submarine arm slot. In relation to a clock, the arm slot can be compared to 4:30. An example of this, would be moneyball pitcher Chad Bradford, as you can see, his release is low to the ground, and his shoulder is tilted downwards.

Former A’s Pitcher Chad Bradford⁴

It is commonly recommended that pitchers often use whatever is most comfortable for them, however, O’Leary suggests that arm slot is instead just dependent on the amount of “shoulder tilt” a pitcher has when throwing, and can be adjusted accordingly to find maximum efficiency.3 Furthermore, a pitcher’s arm slot can predispose them to injury, if it is inefficient, and requires dramatic compensation in arm whip due to a lack of total body use. This will lead to increased force at the shoulder and elbow joints, creating likelihood of injury.

For a pitcher, it is important to fine tune their kinematic motion to become efficient and increase velocity without significantly increasing kinetic force created at the shoulder and elbow.1 Finding the right arm slot which does this, will lead to decreased likelihood of injury and maximum efficiency.

Works Cited

1Fortenbaugh, D., Fleisig, G. S., & Andrews, J. R. (2009). Baseball Pitching Biomechanics in Relation to Injury Risk and Performance. Sports Health: A Multidisciplinary Approach, 1(4), 314-320. doi:10.1177/1941738109338546

2Lentzner, M., & Said..., B. L. (2008, November 13). A pitching model: Playing the slots. Retrieved September 30, 2016, from http://www.hardballtimes.com/a-pitching-model-playing-the-slots1/

3O'Leary, C. (2007, January 29). The Great Arm Slot Myth. Retrieved September 30, 2016, from http://www.chrisoleary.com/projects/pitchingmechanics101/essays/ArmSlot.html

Picture Citations

1Chris Sale in All-Star form during White Sox's 8-2 victory over Angels [Chris Sale Pitching]. (2015, August 11). Retrieved September 29, 2016, from https://article.wn.com/view/2015/08/11/Chris_Sale_in_AllStar_form_during_White_Soxs_82_victory_over/

2External Rotation | Talk Velocity | TopVelocity Baseball Forum [Pitching Arm Slot]. (2012, January 17). Retrieved September 29, 2016, from http://www.topvelocity.net/forum/talk-velocity/external-rotation/

3O'Leary, C. (2007, November 28). Examples - Arm Slot and Shoulde Tilt [Hideki Okajima]. Retrieved from www.chrisoleary.com

4Submarine Style Baseball Pitchers [Digital image]. (2009, April 16). Retrieved September 29, 2016, from http://hurtyelbow.typepad.com/hurtyelbow/2009/04/submarine-style-baseball-pitchers.html