Movement of the Elite: The science behind high level performance
World famous athletes, legends of sport, and the select few coaches who train them have utilized the principles of biomechanics to perform at elite levels for decades. However, for the greater whole of humanity, these principles remain largely unknown. Like most scientific information, it tends to stay at the very tip top, rarely reaching the lower levels to be utilized by young athletes. In the following article, I will break down one of the most important principles in biomechanics that every coach and athlete should know.
All overhead throwing motions, as well as most movements in sport that require power to be generated at our limbs, share universal principles. One of the most crucial is called the Kinetic Chain. In the kinetic chain, an athlete generates energy from the ground and then transfers that energy upwards, through different body segments in a specific sequence. It ends with the transfer of that energy to a ball at release, as in sports like baseball, football, and the javelin throw, or at ball contact during the golf or baseball swing, tennis serve, or spike in volleyball.
The proper sequence of the kinetic chain in the overhead throwing motion is as follows:
- The hips/pelvis rotates first,
- The torso rotates second, and
- The arm rotates third.
The primary reason the kinetic chain generates peak arm velocity is that it exploits our muscles ability to generate elastic or potential energy. The potential energy generated is then utilized to promote stronger muscle contractions, and subsequently, increased arm velocity.
In the kinetic chain, an athlete generates energy from the ground and then transfers that energy upwards, through different body segments in a specific sequence.
At this point I should remind you that the explanation above is a simple way to both define the sequence and allow you to picture this series of movements visually. Let me be very clear, the kinetic chain is one of the most difficult and counterintuitive series of coordinated body movements that takes a high level of training and athleticism to perform. Luckily for us, science was able to crack the code and allow us to understand what’s really going on, which brings up a very interesting question: Was it because of science that human movement and athleticism evolved to this point, or did science simply reveal the elements of what the best athletes were already doing naturally? And if so, should we use this as a way to screen and test for high level athleticism, and/or do we invest in this knowledge and mass produce it on a large scale to improve the odds of athletic potential? Is it even worth it? Arguments can be made on both sides, but ultimately these principles have been extensively studied, vetted, and proven to be the method that the elite use to obtain athletic excellence, and for a very select few, fame, fortune, and immortalization.
But I digress.
In order to actually perform this complex sequence correctly and efficiently, an athlete must be able to perform counter movements. A counter movement occurs when two segments of the body are moving in opposite directions. For example, visualize how the torso and arm move during a baseball pitch. If done correctly, a right-handed pitcher will rotate their torso counter-clockwise towards the batter, and at the very same time the arm will rotate in the opposite or clockwise direction as it moves into external rotation.
This simultaneous opposition causes a pre-stretch or eccentric contraction to occur, allowing the internal rotators of the shoulder, the muscles responsible for accelerating the arm forward, to build elastic energy, which we know is essential to increasing the force of muscle contractions and ultimately arm velocity and pitch speed. Counter movements are the result of the coordinated activation of muscles at neighboring body segments that cause opposition. And because we know the three phases of the kinetic chain (hip, then torso, then arm), we can now figure out which muscle groups and motor patterns are essential to perform the sequence properly.
Let me be very clear, the kinetic chain is one of the most difficult and counterintuitive series of coordinated body movements that takes a high level of training and athleticism to perform.
The Kinetic Chain — Phase 1: Hip/Pelvis Rotation
Continuing with our example of a pitcher, the first phase of the kinetic chain, and first counter movement is the forward rotation of the pelvis and simultaneous backward rotation of the torso. This occurs during the large stride towards home plate, which generates a large portion of the energy necessary to begin the kinetic chain. The primary muscles to be concerned with are the right gluteus maximus (glute for short), which is responsible for rotating the pelvis or hip forward in the counterclockwise direction, and the left external oblique of the torso, which causes the torso to remain open or rotate backwards in the clockwise direction (this is not the only muscle of the torso active during this movement, it’s simply used for ease of explanation and visualization). It’s the simultaneous activation of the right gluteus maximus and the left external oblique that causes the pelvis and torso to move in opposite (counter) directions, resulting in the eccentric loading (building of elastic energy) of the opposite side of the body or right external oblique and corresponding core musculature.
We’ve now separated the body into two pieces: the lower half including the pelvis and lower legs, which is now facing forward or ‘closed’ to the batter, and the upper half collectively referred to as the torso, which is still ‘open’ or perpendicular to the pelvis.
To visualize it another way, imagine yourself twisting a tall thin block of rubber. To do so, one hand would grip the top of the block and the other would grip the bottom. When you rotate your hands in opposite directions you would see the block visibly twisting, and like the muscles of the torso, the block would build elastic/potential energy. When you release the top hand, the block would rapidly rotate back to its original position. The separation of the hip/pelvis, commonly known as hip/shoulder separation is one of the most important factors and predictors of peak arm velocity. The further these two segments are separated (to a certain extent), the more elastic energy can be generated in the core musculature, and increased potential for velocity. Which in the case of a pitcher, quarterback, javelin thrower, and volleyball player is an extremely important and fundamental element for high level performance.
The separation of the hip/pelvis, commonly known as hip/shoulder separation is one of the most important factors and predictors of peak arm velocity.
The Kinetic Chain — Phase 2: Torso Rotation
Phase two of the kinetic chain, and second counter motion, is the forward or clockwise rotation of the torso, and the simultaneous backwards or counterclockwise rotation of the right arm (known as shoulder external rotation). The muscles responsible for this counter movement include the right external oblique (again emphasized for ease of explanation and visualization), which is responsible for rotating the torso forward, and the external rotators of the shoulder (infraspinatus, supraspinatus, and teres minor), which are attached to the back of the humerus or upper arm bone, and are responsible for the external or backward rotation of the arm in the shoulder socket. It’s the rapid, simultaneous, and oppositional rotation of the torso and arm that allows the internal rotators (pectoralis major, latissimus dorsi, and subscapularis), also known as the accelerators of the arm, to build elastic/potential energy.
To picture it visually, imagine the muscles that attach to the front of the arm (the internal rotators), the ones responsible for propelling the arm forward, like the rubber bands of a slingshot. When the arm is forcefully propelled backwards into external rotation, it’s as if the rubber bands in the sling shot are being pulled backwards or stretched, in order to build elastic/potential energy.
The Kinetic Chain — Phase 3: Arm Rotation
The final stage of the kinetic chain is the rapid internal rotation and acceleration of the arm forward, transferring the energy generated from the ground and through the body to the ball at release. In our sling shot example this is the moment the sling is released, in which the elastic/potential energy generated during the stretch of the rubber bands becomes kinetic energy, rapidly propelling the projectile, or in this case the arm, forward.
In summary, the kinetic chain is the single most important factor when creating peak arm velocity. Its application can be seen across multiple sports, with those at the highest levels exhibiting a mastery of the sequence. Its effectiveness originates from our muscles ability to generate elastic/potential energy, which allows for stronger muscle contractions and ultimately, increased arm velocity. A knowledge of the proper sequence, important counter movements, and a few key principles of muscle physiology, are the first steps in reaping the benefits of this complex and obscure movement pattern.
