How many of you have heard pitching coaches yell out “find your balance point, just throw strikes, finish off square to the plate, rare back and fire, throw hard now”, etc… ? I had coaches like that too growing up and guess what… They don’t know what they are talking about.
Throwing, just like any other complex movement, requires many moving parts to flow in the correct sequence. When executed correctly, it should create a single effortless motion. Just throwing the ball is too general; we must be able to throw the ball on a downward plane with the most velocity as possible while putting the least amount of stress on the weaker links (UCL/Rotor-cuff) within the kinetic chain which is throwing.
First, let’s split the human body up into 3 main components of power generation. Starting from the ground up, first we have the lower body composed of feet, ankle joints, lower legs (tibia, fibula), knee joint, and upper-leg (femur) all connecting at the pelvis (hip joint.) Second, is where the majority of power is generated and that is the core. The bone supporting the core is the lumbar spine, where the range of motion is the greatest giving the core the ability to create torque. Third, there is the upper torso and arms. This portion of the human machine is the most complex and the majority of throwing injuries occurs in the shoulder or elbow due to the immense stress these joints have to withstand with each throw. The Brain Controls everything! Now to see how we can use each component to the highest mechanical advantage our anatomy allows.
The lower body must be separated into two subdivision, legs and pelvis (hips). The sole purpose of the legs is to create as much speed (distance/time) going towards the target, then stopping as abruptly as possible, which will in turn, speed up the upper-body rotation, maximizing the power output at the point of release. Think of this reaction in terms of a car crash. If a car with a stack of books on the passenger seat drives at 100mph and hits an immobile wall, the cars velocity will drop to zero but the books will continue to fly through the windshield at the original 100mph. The Pelvis (hips) also has major part in the throwing process. Its job is to simply load up (rotate away from target) in the beginning of the motion and to unwind in sync with the landing foot as the legs propel the thrower towards the target.
The best way to visualize the core is as a very thick coil attaching the upper and lower components. Although the majority of the power generated in the proper throwing motion is produced by the core, it is the simplest process in this kinetic chain. To use the core to its maximum potential the thrower must simply load the upper and lower components simultaneously in the beginning of the delivery and keep the upper body loaded (closed) as much as possible till the front foot plants. At this point, the more separation there is between pelvic and upper torso lines, the more torque the core can produce. This is the true meaning of commonly misused term “staying closed”. The separation of the Pelvic and Shoulder lines creates the most range of motion for the already stretched core to explosively rotate; this rotation will be the main source of velocity for the thrower.
The last but not least of the three components is the upper torso. The main goal of the upper torso is to achieve maximum Scapula load, and to maintain the greatest amount of separation from the Pelvic line till the front foot plants. This will all lead to maximum external rotation of the throwing arm which will directly increase velocity. The most efficient way to load ones Scapula is to do so as naturally and effortlessly as possible. The arms actually have tracks, just like trains do. If the train falls off the track, it doesn’t run. This track differs for each individual. To figure out where your track is, stand up with good posture and let your arms hang down to your sides and swing your arms forward and backwards. You will see your arms will naturally want to stay close to the body and swing on a Chest-Back plane. This Chest-Back plane does not ever change, no matter what. As the arms travel on the natural track, the elbows will fire towards each other squeezing the shoulder blades together while the chest expands. This is called scapula load. This Scapula load will occur right as the front foot strikes the ground and plants. This is when the loaded shoulders explosively rotate driving the throwing shoulder up and over towards the target line. The actual release of the baseball is done so by the extension, pronation, internal rotation and wrist flexion of the throwing arm. After the ball is released, the shoulder rotation will come to a stop to do structural limitations, but the now accelerated throwing arm will keep going until it hits the rib cage and comes to a stop. This method of deceleration is the most natural and puts the least amount of stress on the decelerator muscles. As a result of the fast upper torso rotation, the back leg will fly up off the ground and come to a soft landing.