This article highlights the best results yielded by applying the laws of motion on a record-setting pitcher. Newton’s three laws of motion, as first articulated in Philosophiae Naturalis Principia Mathematica (1687), form the basis for classical Newtonian mechanics and provide the relationships between forces acting on a body and the consequent motion of the body. These laws govern the relationships of objects present in our physical universe, including the human body. According to Marshall, pitchers of all ages would be very well served by learning and applying the three laws of motion correctly, as the forces generated by the body can be very destructive if bad habits are learned and repeated. Kinesiologists study Newton’s laws with respect to human movement. According to Marshall, the laws of motion can be converted to laws of force application that explain how athletes should apply force to projectiles, including themselves. According to Marshall, the traditional pitching techniques are almost always taught with a minimal understanding of the underlying biomechanics, and frequently just copy the most popular pitchers of the era.
Shortly after completing his first season in the major leagues with the 1967 Detroit Tigers, Mike Marshall noticed, while shaving, that he could not fully extend or flex the elbow of his pitching arm. Concerned about the apparent loss of range in motion, he wanted to find out why this had happened.
Although he had started out professionally as a shortstop, Marshall made a successful transition to pitching. With the coaching provided by the Tigers organization and the physical education degree he had earned from Michigan State University, he had no reason to suspect he was executing the pitching motion with any mechanical flaws or potential problems.
However, X-rays of his pitching arm revealed that, in addition to noticeable deformities to his pitching elbow, he had suffered a loss of 24 degrees in the total range of motion (both flexion and extension). Mad as hell, Marshall set out to discover how he could correct the mechanical flaws inherent with the traditional pitching motion, and help others avoid the pain, discomfort, and skeletal deformities that all too frequently accompany this activity.
While Marshall at the time was only in his mid-20s and didn’t have everything figured out yet, he did know enough to realize that the “traditional” pitching methodologies espoused by his coaches ran contrary to the laws of physics. Handed down from earlier generations, these methodologies never had been seriously questioned or examined for flaws—flaws which Marshall was determined to discover and correct.
He believes he found answers by going back to basics. According to Marshall, to correct the mechanical flaws in traditional pitching methods, we must consult the ideas of a man who never witnessed a baseball game, let alone attempted to throw a baseball at the 90-plus mph velocities common among modern major league pitchers—Sir Isaac Newton.
Newton’s three laws of motion, as first articulated in Philosophiae Naturalis Principia Mathematica (1687), form the basis for classical Newtonian mechanics and provide the relationships between forces acting on a body and the consequent motion of the body. These laws govern the relationships of objects present in our physical universe, including the human body.
Mike Marshall received a Ph.D. in exercise physiology from Michigan State University in 1978. Among his specialties is biomechanics. Combining his knowledge of physics, anatomy, kinesiology, and baseball, Marshall has painstakingly worked out pitching methods that differ on many points from the practices taught by traditional coaches. His ideas are not widely accepted in baseball circles.
Despite his impediment, Marshall went on to enjoy a major league career that spanned 14 years. He set several pitching records in the 1970s that still stand. He attributes his athletic success to the pitching principles that he researched and developed on the field.
According to Marshall, pitchers of all ages would be very well served by learning and applying the three laws of motion correctly, as the forces generated by the body can be very destructive if bad habits are learned and repeated. While correct pitching form won’t guarantee major-league success, it will certainly reduce the likelihood of damage to the body in general, and to the pitching arm in particular.
The First Law of Motion is the law of inertia: “A body remains at rest, or if in motion, it remains in uniform motion with constant speed in a straight line, unless it is acted on by an unbalanced external force.”
When Sir Isaac Newton determined that moving objects continue with constant velocity in a straight line, he refuted Aristotle’s theory that objects were in their natural states only when at rest.
A baseball starts at rest in a pitcher’s glove. However, gravity is an external force that constantly acts on a baseball (and everything else on Earth). Therefore, while a pitcher must apply force to a baseball to achieve maximum release velocity, he also must constantly overcome the downward accelerative force of gravity (9.8 m/s2).
Once a baseball is acted upon by an unbalanced external force (when a pitcher begins his wind-up), it will move with constant velocity in a straight line. (For purposes of this analysis, we are only concerned with the pitching motion itself, and do not examine the forces that act upon a baseball after it is released—down-ward gravitational force and air resistance.) Therefore, if a pitcher moves a baseball in a non-straight line (such as an arc), he must apply additional force to overcome the straight-line inertial pathway the baseball wants to follow, tangent to any moment on the arc traced by the pitcher’s throwing hand. This wastes force.
Curved or arced force applications waste force in two ways. First, they require a pitcher to constantly redirect the mass of the baseball. Second, they divert force away from straight-line applications. When a pitcher applies force side-to-side (movement toward first or third base), and up-and-down (bending forward or dropping the rear knee), in addition to force toward home plate, only the application of force toward home plate influences release velocity.
The Second Law of Motion is the law of acceleration: “The resultant force impressed upon an object is equal to the mass of the object multiplied by its acceleration, or F = ma.”
A pitcher frequently wants to maximize the velocity of a pitch. Therefore, we must examine what variables influence force applications at the moment of release, or release velocity.
Isolating acceleration provides us with: a = F/m.
The weight of a baseball “shall weigh not less than five nor more than 5 1/4 ounces avoirdupois,” according to Major League Baseball Official Rules, “Objectives of the Game,” 1.09. This provides us with a mass of 142 to 149 grams. However, we will use 0.146 kg for our analysis. This leaves us with only the acceleration term to work with to maximize force towards home plate.
We also have an equation for final velocity, vf = v0 + at, to assist us.
We shall let v0 = 0, as the baseball begins its acceleration towards home plate initially at rest. And, substituting a = F/m, we now have the equation Vf = Ft/m.
The release velocity of a pitched baseball equals the amount of straight-line force applied toward home plate multiplied by the time period over which a pitcher applies force divided by mass. Therefore, the only variables that determine release velocity are application of straight-line force toward home plate and the time period over which the force is applied.
A uniform acceleration study, conducted by Marshall himself, has determined that pitchers apply force from first forward movement to release for approximately 0.2 second. If we assume that pitchers want release velocities of at least 90 miles per hour (40.2 m/s), then we can determine how much straight-line, toward-homeplate force they must apply for 0.2 second.
Substituting our findings into the equation Vf = Ft/m, we have Vf = 40.2 m/s, t = 0.2 s, and m = 0.146 kg. We find that F, or applied force, is equal to 29.35 newtons, or 6.6 1bs.
The release (or final) velocity formula shows that when a pitcher applies 29.35 newtons of straight-line force toward home plate for 0.2 second, he achieves a release velocity of 40.2 m/s, or 90 mph. To better understand the interrelationship among release velocity, force, and application time, let us assume the following:
Suppose a pitcher decreases his force application time by 0.05 second. Now the force required for him to achieve 40.2 m/s release velocity increases to 39.13 newtons, or 8.8 lbs. Therefore, the application time linearly impacts the amount of force that pitchers must apply to achieve the desired release velocity. Conversely, when a pitcher applies 29.35 newtons for 0.22 second, then he achieves a release velocity of 44.2 m/s, or 99 mph.
The Third Law of Motion is the law of reaction: “For every action force, there is an equal and oppositely directed reaction force.”
The law of reaction requires that pitchers apply force toward second base equal to the force they apply to baseballs directed toward home plate. If a pitcher wants to apply greater force to his baseball pitch, he must apply greater force toward second base. A pitcher has different ways to apply his oppositely directed force.
A pitcher must apply force against the pitching rubber with his rear leg to start his body moving forward. At one time, pitching coaches instructed pitchers to powerfully drive against the pitching rubber. However, when pitchers began developing serious shoulder injuries, emphasis on the rear leg drive was curtailed.
Some recent pitching coaches have recommended that pitchers not push off the pitching rubber at all, but should simply fall forward towards home plate. The law of reaction requires pitchers to push off the pitching rubber, but the positioning of the pitching arm is critical.
An alternative is to apply force against the ground. The ground provides a pitcher with a resistance against which to apply oppositely directed force. To achieve greater oppositely directed force, pitchers can drive off their stride legs.
The stride leg drive technique also lengthens the driveline over which a pitcher applies force to the baseball Increasing the length of the driveline increases the application time of force.
Pitchers require hundreds of hours of training to learn how to incorporate inertial resistance into their equal and oppositely directed forces.
Kinesiologists study Newton’s laws with respect to human movement. According to Marshall, the laws of motion can be converted to laws of force application that explain how athletes should apply force to projectiles, including themselves.
The first law of force application requires pitchers to apply straight-line force toward home plate only. To achieve maximum release velocity, a pitcher must apply straight-line force from “ready” position, continuing through release.
In a traditional pitching motion, a pitcher pulls his pitching arm across his body. Therefore, he applies force in an arc, and at every moment tangent to that arc, the baseball’s inertia wants to fly off in a straight line. These actions greatly reduce the consistency of the release and waste force.
Another flaw is for pitchers to reverse rotate the acromial line beyond alignment with home plate. The acromial line runs from the edge of one shoulder to the other. Think of it as the shoulder line. When a pitcher reverse rotates his acromial line beyond second base, he takes the baseball laterally behind his body. He must return it to his pitching arm side before throwing it toward home plate.
This creates centripetal force that swings the forearm horizontally outside of vertical in an arc, requiring a pitcher to constantly redirect the baseball.
Finally, when a pitcher turns his rear foot to parallel with the pitching rubber, he increases the likelihood that he will reverse rotate his acromial line beyond second base, resulting in the forearm circling outward and force being applied in an arc.
The aggregate of these flaws, in addition to less consistent pitch accuracy, is unnecessary stress and damage to the elbow, as well as to the rotator cuff muscles of the shoulder.
According to Marshall, from the moment a pitcher’s elbow starts forward until the tip of his middle finger stops, he must apply straight-line force toward home plate.
This reduces the unnecessary force that bones, ligaments, tendons, and muscles must overcome. Also, to powerfully rotate his shoulders forward, the pitcher must stand tall and keep his trunk vertical. Then, not only will he rotate perpendicularly around the vertical axis of his body, but he will also use all his height to his advantage.
Finally, a pitcher must powerfully pronate the forearm, meaning he downwardly rotates his thumb, through release. In 1967, high-speed film showed Marshall that he supinated his forearm—turned it palm up—when he threw his slider. As a result, he slammed the bones in the back of his pitching elbow together, the result of which was to decrease his extension range of motion.
However, when he pronated the release of his fastball, because the pronator teres muscle also flexes the elbow, he prevented these two bones from slamming together. Therefore, Marshall learned how to pronate the release of every type of pitch, including his slider.
Taken in aggregate, these actions greatly reduce the likelihood of injury.
The second law requires that, to achieve maximum release velocity, a pitcher must uniformly apply force over a greater distance.
In the traditional pitching motion, when a pitcher squares his shoulders to home plate upon release (brings his acromial line to perpendicular with home plate), he prematurely interrupts force application distance.
By striding as far forward as possible, he stops the forward movement of the center of mass of the body and leaves the foot of his real leg near the pitching rubber, which limits the movement of his rear hip. These actions also limit the force application distance. To compensate, a traditional pitcher must apply greater force over a shorter distance, leading to unnecessary stress on the pitching arm.
Marshall recommends that, to lengthen driveline distance, a pitcher must reach backward and upward to driveline height while reverse rotating his acromial line to point toward second base. This places the baseball on the driveline path as far from home plate as possible.
A pitcher must land with his front foot to the glove arm side of the line toward home plate with his toes pointed outward and move his rear hip, leg, and shoulder ahead of his front foot. After he forwardly rotates his acromial line to point toward home plate, he positions his elbow as close to home plate as possible when releasing the baseball.
These actions not only reduce unnecessary pitching arm stress, but also decrease the distance a pitch must travel to home plate, resulting in “stealth” velocity.
The third law of force application requires a pitcher to apply greater force toward second base. To achieve maximum release velocity, a pitcher must uniformly move his center of mass through release.
The traditional pitching motion—powerfully pushing or jumping off the pitching rubber—accelerates the center of mass too quickly, and does not uniformly move the center of mass forward in relation to the pitching arm. When a pitcher strides forward as far as possible, he stops the forward movement of the center of mass of his body.
Marshall recommends that a pitcher walk straight forward off the pitching rubber, applying force directly toward second base with his rear foot. After the front foot contacts the ground, a pitcher must move his center of mass ahead of it, applying force toward second base with his front foot.
To initiate the rotation of his shoulders around the vertical axis of his body, a pitcher must pull his glove forearm straight backward toward second base. These actions uniformly move the center of mass straight forward.
Finally, in a coupling of parallel and oppositely directed forces, a pitcher should strongly push back with his front foot while simultaneously accelerating the baseball through release with his pitching arm. These parallel and oppositely directed forces significantly increase release velocity.
The act of throwing a baseball shouldn’t be a painful experience, but unfortunately, it is for many, and at alarmingly young ages. According to Marshall, the traditional pitching techniques are almost always taught with a minimal understanding of the underlying biomechanics, and frequently just copy the most popular pitchers of the era.
He argues that this practice must be replaced with the vastly increased knowledge and understanding we have acquired through medical science of the human body, how it operates, and how it will signal to us to correct flaws in our treatment of it, oftentimes through pain, discomfort, and even by breaking down when we overuse it.
Marshall claims that his pitching motion has made every attempt to distill the most current knowledge and research available into a motion that does not compromise a person’s physical health, enjoyment of the game, or natural talents.
When tackling the most daunting physical challenges, it is frequently possible to move forward by going back to the basics of our engineering fore-fathers. In Marshall’s case, he resorted to the late 17th century for a coach who helped him become a 14-year major league veteran, set several pitching records, and improve upon the techniques entrenched in the minds of many modern coaches. The man is Sir Isaac Newton.